National Library of Energy BETA

Sample records for massively parallel microcell-based

  1. Massive Parallel Quantum Computer Simulator

    E-Print Network [OSTI]

    K. De Raedt; K. Michielsen; H. De Raedt; B. Trieu; G. Arnold; M. Richter; Th. Lippert; H. Watanabe; N. Ito

    2006-08-30

    We describe portable software to simulate universal quantum computers on massive parallel computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray X1E, a SGI Altix 3700 and clusters of PCs running Windows XP. We study the performance of the software by simulating quantum computers containing up to 36 qubits, using up to 4096 processors and up to 1 TB of memory. Our results demonstrate that the simulator exhibits nearly ideal scaling as a function of the number of processors and suggest that the simulation software described in this paper may also serve as benchmark for testing high-end parallel computers.

  2. A Massively Parallel Solver for the Mechanical Harmonic Analysis...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: A Massively Parallel Solver for the Mechanical Harmonic Analysis of Accelerator Cavities Citation Details In-Document Search Title: A Massively Parallel Solver...

  3. Template based parallel checkpointing in a massively parallel computer system

    DOE Patents [OSTI]

    Archer, Charles Jens (Rochester, MN); Inglett, Todd Alan (Rochester, MN)

    2009-01-13

    A method and apparatus for a template based parallel checkpoint save for a massively parallel super computer system using a parallel variation of the rsync protocol, and network broadcast. In preferred embodiments, the checkpoint data for each node is compared to a template checkpoint file that resides in the storage and that was previously produced. Embodiments herein greatly decrease the amount of data that must be transmitted and stored for faster checkpointing and increased efficiency of the computer system. Embodiments are directed to a parallel computer system with nodes arranged in a cluster with a high speed interconnect that can perform broadcast communication. The checkpoint contains a set of actual small data blocks with their corresponding checksums from all nodes in the system. The data blocks may be compressed using conventional non-lossy data compression algorithms to further reduce the overall checkpoint size.

  4. MEMS-based Massively-parallelized Mechanoporation Instrumentation for Ultrahigh Throughput Cellular Manipulation

    E-Print Network [OSTI]

    Zhang, Yanyan

    2012-01-01

    OF CALIFORNIA RIVERSIDE MEMS-based Massively-parallelizedOF THE DISSERTATION MEMS-based Massively-parallelizeda massively- parallelized MEMS-based platform for passively

  5. MASSIVE HYBRID PARALLELISM FOR FULLY IMPLICIT MULTIPHYSICS

    SciTech Connect (OSTI)

    Cody J. Permann; David Andrs; John W. Peterson; Derek R. Gaston

    2013-05-01

    As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided.

  6. PFLOTRAN User Manual: A Massively Parallel Reactive Flow and...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: PFLOTRAN User Manual: A Massively Parallel Reactive Flow and Transport Model for Describing Surface and Subsurface Processes Citation Details In-Document Search...

  7. PFLOTRAN User Manual: A Massively Parallel Reactive Flow and...

    Office of Scientific and Technical Information (OSTI)

    PFLOTRAN User Manual: A Massively Parallel Reactive Flow and Transport Model for Describing Surface and Subsurface Processes Lichtner, Peter OFM Research; Karra, Satish Los...

  8. 2-SATISFIABILITY AND DIAGNOSING FAULTY PROCESSORS MASSIVELY PARALLEL COMPUTING SYSTEMS

    E-Print Network [OSTI]

    Servatius, Brigitte

    2-SATISFIABILITY AND DIAGNOSING FAULTY PROCESSORS IN MASSIVELY PARALLEL COMPUTING SYSTEMS ANSUMAN the number of processors in the system. 1. Introduction In a massively parallel computing system, such as CM be used more often. In multi-processor computers there are two different system modes, a normal operation

  9. Tsunami: Massively Parallel Homomorphic Hashing on Many-core GPUs

    E-Print Network [OSTI]

    Li, Zongpeng

    1 Tsunami: Massively Parallel Homomorphic Hashing on Many-core GPUs Xiaowen Chu Department. In this paper, we present a massively parallel solution, named Tsunami, by exploiting the widely available many-core Graphic Processing Units (GPUs). Tsunami includes the following optimization techniques to achieve

  10. Shift: A Massively Parallel Monte Carlo Radiation Transport Package

    SciTech Connect (OSTI)

    Pandya, Tara M [ORNL; Johnson, Seth R [ORNL; Davidson, Gregory G [ORNL; Evans, Thomas M [ORNL; Hamilton, Steven P [ORNL

    2015-01-01

    This paper discusses the massively-parallel Monte Carlo radiation transport package, Shift, de- veloped at Oak Ridge National Laboratory. It reviews the capabilities, implementation, and parallel performance of this code package. Scaling results demonstrate very good strong and weak scaling behavior of the implemented algorithms. Benchmark results from various reactor problems show that Shift results compare well to other contemporary Monte Carlo codes and experimental results.

  11. Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer

    E-Print Network [OSTI]

    2008-01-01

    MASSIVELY-PARALLEL ELECTRICAL-CONDUCTIVITY IMAGING OFconsiderable attention for electrical conductivity mappingand anisotropic (blue) electrical conductivity. Fig. 1 Fig.

  12. Routing performance analysis and optimization within a massively parallel computer

    DOE Patents [OSTI]

    Archer, Charles Jens; Peters, Amanda; Pinnow, Kurt Walter; Swartz, Brent Allen

    2013-04-16

    An apparatus, program product and method optimize the operation of a massively parallel computer system by, in part, receiving actual performance data concerning an application executed by the plurality of interconnected nodes, and analyzing the actual performance data to identify an actual performance pattern. A desired performance pattern may be determined for the application, and an algorithm may be selected from among a plurality of algorithms stored within a memory, the algorithm being configured to achieve the desired performance pattern based on the actual performance data.

  13. A massively parallel fractional step solver for incompressible flows

    SciTech Connect (OSTI)

    Houzeaux, G. Vazquez, M. Aubry, R. Cela, J.M.

    2009-09-20

    This paper presents a parallel implementation of fractional solvers for the incompressible Navier-Stokes equations using an algebraic approach. Under this framework, predictor-corrector and incremental projection schemes are seen as sub-classes of the same class, making apparent its differences and similarities. An additional advantage of this approach is to set a common basis for a parallelization strategy, which can be extended to other split techniques or to compressible flows. The predictor-corrector scheme consists in solving the momentum equation and a modified 'continuity' equation (namely a simple iteration for the pressure Schur complement) consecutively in order to converge to the monolithic solution, thus avoiding fractional errors. On the other hand, the incremental projection scheme solves only one iteration of the predictor-corrector per time step and adds a correction equation to fulfill the mass conservation. As shown in the paper, these two schemes are very well suited for massively parallel implementation. In fact, when compared with monolithic schemes, simpler solvers and preconditioners can be used to solve the non-symmetric momentum equations (GMRES, Bi-CGSTAB) and to solve the symmetric continuity equation (CG, Deflated CG). This gives good speedup properties of the algorithm. The implementation of the mesh partitioning technique is presented, as well as the parallel performances and speedups for thousands of processors.

  14. Massively parallel processor networks with optical express channels

    DOE Patents [OSTI]

    Deri, R.J.; Brooks, E.D. III; Haigh, R.E.; DeGroot, A.J.

    1999-08-24

    An optical method for separating and routing local and express channel data comprises interconnecting the nodes in a network with fiber optic cables. A single fiber optic cable carries both express channel traffic and local channel traffic, e.g., in a massively parallel processor (MPP) network. Express channel traffic is placed on, or filtered from, the fiber optic cable at a light frequency or a color different from that of the local channel traffic. The express channel traffic is thus placed on a light carrier that skips over the local intermediate nodes one-by-one by reflecting off of selective mirrors placed at each local node. The local-channel-traffic light carriers pass through the selective mirrors and are not reflected. A single fiber optic cable can thus be threaded throughout a three-dimensional matrix of nodes with the x,y,z directions of propagation encoded by the color of the respective light carriers for both local and express channel traffic. Thus frequency division multiple access is used to hierarchically separate the local and express channels to eliminate the bucket brigade latencies that would otherwise result if the express traffic had to hop between every local node to reach its ultimate destination. 3 figs.

  15. Comparing current cluster, massively parallel, and accelerated systems

    SciTech Connect (OSTI)

    Barker, Kevin J; Davis, Kei; Hoisie, Adolfy; Kerbyson, Darren J; Pakin, Scott; Lang, Mike; Sancho Pitarch, Jose C

    2010-01-01

    Currently there is large architectural diversity in high perfonnance computing systems. They include 'commodity' cluster systems that optimize per-node performance for small jobs, massively parallel processors (MPPs) that optimize aggregate perfonnance for large jobs, and accelerated systems that optimize both per-node and aggregate performance but only for applications custom-designed to take advantage of such systems. Because of these dissimilarities, meaningful comparisons of achievable performance are not straightforward. In this work we utilize a methodology that combines both empirical analysis and performance modeling to compare clusters (represented by a 4,352-core IB cluster), MPPs (represented by a 147,456-core BG/P), and accelerated systems (represented by the 129,600-core Roadrunner) across a workload of four applications. Strengths of our approach include the ability to compare architectures - as opposed to specific implementations of an architecture - attribute each application's performance bottlenecks to characteristics unique to each system, and to explore performance scenarios in advance of their availability for measurement. Our analysis illustrates that application performance is essentially unrelated to relative peak performance but that application performance can be both predicted and explained using modeling.

  16. Massively parallel processor networks with optical express channels

    DOE Patents [OSTI]

    Deri, Robert J. (Pleasanton, CA); Brooks, III, Eugene D. (Livermore, CA); Haigh, Ronald E. (Tracy, CA); DeGroot, Anthony J. (Castro Valley, CA)

    1999-01-01

    An optical method for separating and routing local and express channel data comprises interconnecting the nodes in a network with fiber optic cables. A single fiber optic cable carries both express channel traffic and local channel traffic, e.g., in a massively parallel processor (MPP) network. Express channel traffic is placed on, or filtered from, the fiber optic cable at a light frequency or a color different from that of the local channel traffic. The express channel traffic is thus placed on a light carrier that skips over the local intermediate nodes one-by-one by reflecting off of selective mirrors placed at each local node. The local-channel-traffic light carriers pass through the selective mirrors and are not reflected. A single fiber optic cable can thus be threaded throughout a three-dimensional matrix of nodes with the x,y,z directions of propagation encoded by the color of the respective light carriers for both local and express channel traffic. Thus frequency division multiple access is used to hierarchically separate the local and express channels to eliminate the bucket brigade latencies that would otherwise result if the express traffic had to hop between every local node to reach its ultimate destination.

  17. Massively parallel solver for the high-order Galerkin Least-Squares method

    E-Print Network [OSTI]

    Yano, Masayuki, Ph. D. Massachusetts Institute of Technology

    2009-01-01

    A high-order Galerkin Least-Squares (GLS) finite element discretization is combined with massively parallel implicit solvers. The stabilization parameter of the GLS discretization is modified to improve the resolution ...

  18. High-quality draft assemblies of mammalian genomes from massively parallel sequence data

    E-Print Network [OSTI]

    Gnerre, Sante

    Massively parallel DNA sequencing technologies are revolutionizing genomics by making it possible to generate billions of relatively short (~100-base) sequence reads at very low cost. Whereas such data can be readily used ...

  19. Massively parallel DNA sequencing: the new frontier in biogeography

    E-Print Network [OSTI]

    Rocha, Luiz A.; Bernal, Moisés A.; Gaither, Michelle R.; Alfaro, Michael E.

    2013-01-01

    2007) Popula? tion  genomics:  whole?genome  analysis  of evolutionary scales.  BMC  Genomics, 13, 403.   Bickford, 2012)  Population  genomics  of  parallel  adaptation  in 

  20. Massively Parallel Simulations of Solar Flares and Plasma Turbulence

    E-Print Network [OSTI]

    Grauer, Rainer

    in space- and astrophysical plasmasystems include solar flares and hydro- or magnetohydrodynamic turbulence a pure MPI parallelization, which, however requires a careful optimization of the multi

  1. Scalable Parallel Algorithms for Massive Scale-free Graphs 

    E-Print Network [OSTI]

    Pearce, Roger Allan

    2013-12-05

    Efficiently storing and processing massive graph data sets is a challenging problem as researchers seek to leverage “Big Data” to answer next-generation scientific questions. New techniques are required to process large ...

  2. SWAMP+: multiple subsequence alignment using associative massive parallelism

    SciTech Connect (OSTI)

    Steinfadt, Shannon Irene [Los Alamos National Laboratory; Baker, Johnnie W [KENT STATE UNIV.

    2010-10-18

    A new parallel algorithm SWAMP+ incorporates the Smith-Waterman sequence alignment on an associative parallel model known as ASC. It is a highly sensitive parallel approach that expands traditional pairwise sequence alignment. This is the first parallel algorithm to provide multiple non-overlapping, non-intersecting subsequence alignments with the accuracy of Smith-Waterman. The efficient algorithm provides multiple alignments similar to BLAST while creating a better workflow for the end users. The parallel portions of the code run in O(m+n) time using m processors. When m = n, the algorithmic analysis becomes O(n) with a coefficient of two, yielding a linear speedup. Implementation of the algorithm on the SIMD ClearSpeed CSX620 confirms this theoretical linear speedup with real timings.

  3. Massive Data-Parallel Swarm Simulation and Visualisation using CUDA

    E-Print Network [OSTI]

    Hinze, Thomas

    for the project was to employ CUDA for simulating natural movement and behaviour of a fish swarm. As a fish swarm by calculating the state of a fish at time ti+1 as a function of the state of the whole swarm at time ti. Since this function is equal for all fishes, the state of the whole swarm can easily be calculated in parallel

  4. Matched filters for coalescing binaries detection on massively parallel computers

    E-Print Network [OSTI]

    Enrico Calzavarini; Laura Sartori; Fabio Schifano; Raffaele Tripiccione; Andrea Vicere'

    2002-07-18

    We discuss some computational problems associated to matched filtering of experimental signals from gravitational wave interferometric detectors in a parallel-processing environment. We then specialize our discussion to the use of the APEmille and apeNEXT processors for this task. Finally, we accurately estimate the performance of an APEmille system on a computational load appropriate for the LIGO and VIRGO experiments, and extrapolate our results to apeNEXT.

  5. A dynamic grouping strategy for implementation of the particle filter on a massively parallel computer

    E-Print Network [OSTI]

    Nakano, Shin'ya

    computer Shin'ya Nakano The Institute of Statistical Mathematics Tachikawa, Tokyo, Japan. shiny@ism.ac.jp Abstract ­ A practical way to implement the parti- cle filter (PF) on a massively parallel computer is dis to be computation- ally expensive in applying to high-dimensional problems because a enormous number of particles

  6. A Massively Parallel Pipeline to Clone DNA Variants and Examine Molecular Phenotypes of Human Disease

    E-Print Network [OSTI]

    Yu, Haiyuan

    A Massively Parallel Pipeline to Clone DNA Variants and Examine Molecular Phenotypes of Human-scanning pipeline integrating high-throughput GFP, yeast two-hybrid (Y2H), and mass spectrometry assays this pipeline to show that disease mutations on protein-protein interaction interfaces are significantly more

  7. Massively parallel Monte Carlo for many-particle simulations on GPUs

    SciTech Connect (OSTI)

    Anderson, Joshua A.; Jankowski, Eric [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Grubb, Thomas L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Engel, Michael [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Glotzer, Sharon C., E-mail: sglotzer@umich.edu [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

    2013-12-01

    Current trends in parallel processors call for the design of efficient massively parallel algorithms for scientific computing. Parallel algorithms for Monte Carlo simulations of thermodynamic ensembles of particles have received little attention because of the inherent serial nature of the statistical sampling. In this paper, we present a massively parallel method that obeys detailed balance and implement it for a system of hard disks on the GPU. We reproduce results of serial high-precision Monte Carlo runs to verify the method. This is a good test case because the hard disk equation of state over the range where the liquid transforms into the solid is particularly sensitive to small deviations away from the balance conditions. On a Tesla K20, our GPU implementation executes over one billion trial moves per second, which is 148 times faster than on a single Intel Xeon E5540 CPU core, enables 27 times better performance per dollar, and cuts energy usage by a factor of 13. With this improved performance we are able to calculate the equation of state for systems of up to one million hard disks. These large system sizes are required in order to probe the nature of the melting transition, which has been debated for the last forty years. In this paper we present the details of our computational method, and discuss the thermodynamics of hard disks separately in a companion paper.

  8. Molecular Dynamics Simulations from SNL's Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Plimpton, Steve; Thompson, Aidan; Crozier, Paul

    LAMMPS (http://lammps.sandia.gov/index.html) stands for Large-scale Atomic/Molecular Massively Parallel Simulator and is a code that can be used to model atoms or, as the LAMMPS website says, as a parallel particle simulator at the atomic, meso, or continuum scale. This Sandia-based website provides a long list of animations from large simulations. These were created using different visualization packages to read LAMMPS output, and each one provides the name of the PI and a brief description of the work done or visualization package used. See also the static images produced from simulations at http://lammps.sandia.gov/pictures.html The foundation paper for LAMMPS is: S. Plimpton, Fast Parallel Algorithms for Short-Range Molecular Dynamics, J Comp Phys, 117, 1-19 (1995), but the website also lists other papers describing contributions to LAMMPS over the years.

  9. The Fortran-P Translator: Towards Automatic Translation of Fortran 77 Programs for Massively Parallel Processors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    O'keefe, Matthew; Parr, Terence; Edgar, B. Kevin; Anderson, Steve; Woodward, Paul; Dietz, Hank

    1995-01-01

    Massively parallel processors (MPPs) hold the promise of extremely high performance that, if realized, could be used to study problems of unprecedented size and complexity. One of the primary stumbling blocks to this promise has been the lack of tools to translate application codes to MPP form. In this article we show how applications codes written in a subset of Fortran 77, called Fortran-P, can be translated to achieve good performance on several massively parallel machines. This subset can express codes that are self-similar, where the algorithm applied to the global data domain is also applied to each subdomain. Wemore »have found many codes that match the Fortran-P programming style and have converted them using our tools. We believe a self-similar coding style will accomplish what a vectorizable style has accomplished for vector machines by allowing the construction of robust, user-friendly, automatic translation systems that increase programmer productivity and generate fast, efficient code for MPPs.« less

  10. User's Guide for TOUGH2-MP - A Massively Parallel Version of the TOUGH2 Code

    SciTech Connect (OSTI)

    Earth Sciences Division; Zhang, Keni; Zhang, Keni; Wu, Yu-Shu; Pruess, Karsten

    2008-05-27

    TOUGH2-MP is a massively parallel (MP) version of the TOUGH2 code, designed for computationally efficient parallel simulation of isothermal and nonisothermal flows of multicomponent, multiphase fluids in one, two, and three-dimensional porous and fractured media. In recent years, computational requirements have become increasingly intensive in large or highly nonlinear problems for applications in areas such as radioactive waste disposal, CO2 geological sequestration, environmental assessment and remediation, reservoir engineering, and groundwater hydrology. The primary objective of developing the parallel-simulation capability is to significantly improve the computational performance of the TOUGH2 family of codes. The particular goal for the parallel simulator is to achieve orders-of-magnitude improvement in computational time for models with ever-increasing complexity. TOUGH2-MP is designed to perform parallel simulation on multi-CPU computational platforms. An earlier version of TOUGH2-MP (V1.0) was based on the TOUGH2 Version 1.4 with EOS3, EOS9, and T2R3D modules, a software previously qualified for applications in the Yucca Mountain project, and was designed for execution on CRAY T3E and IBM SP supercomputers. The current version of TOUGH2-MP (V2.0) includes all fluid property modules of the standard version TOUGH2 V2.0. It provides computationally efficient capabilities using supercomputers, Linux clusters, or multi-core PCs, and also offers many user-friendly features. The parallel simulator inherits all process capabilities from V2.0 together with additional capabilities for handling fractured media from V1.4. This report provides a quick starting guide on how to set up and run the TOUGH2-MP program for users with a basic knowledge of running the (standard) version TOUGH2 code, The report also gives a brief technical description of the code, including a discussion of parallel methodology, code structure, as well as mathematical and numerical methods used. To familiarize users with the parallel code, illustrative sample problems are presented.

  11. 3-D readout-electronics packaging for high-bandwidth massively paralleled imager

    DOE Patents [OSTI]

    Kwiatkowski, Kris (Los Alamos, NM); Lyke, James (Albuquerque, NM)

    2007-12-18

    Dense, massively parallel signal processing electronics are co-packaged behind associated sensor pixels. Microchips containing a linear or bilinear arrangement of photo-sensors, together with associated complex electronics, are integrated into a simple 3-D structure (a "mirror cube"). An array of photo-sensitive cells are disposed on a stacked CMOS chip's surface at a 45.degree. angle from light reflecting mirror surfaces formed on a neighboring CMOS chip surface. Image processing electronics are held within the stacked CMOS chip layers. Electrical connections couple each of said stacked CMOS chip layers and a distribution grid, the connections for distributing power and signals to components associated with each stacked CSMO chip layer.

  12. A Massively Parallel Sparse Eigensolver for Structural Dynamics Finite Element Analysis

    SciTech Connect (OSTI)

    Day, David M.; Reese, G.M.

    1999-05-01

    Eigenanalysis is a critical component of structural dynamics which is essential for determinating the vibrational response of systems. This effort addresses the development of numerical algorithms associated with scalable eigensolver techniques suitable for use on massively parallel, distributed memory computers that are capable of solving large scale structural dynamics problems. An iterative Lanczos method was determined to be the best choice for the application. Scalability of the eigenproblem depends on scalability of the underlying linear solver. A multi-level solver (FETI) was selected as most promising for this component. Issues relating to heterogeneous materials, mechanisms and multipoint constraints have been examined, and the linear solver algorithm has been developed to incorporate features that result in a scalable, robust algorithm for practical structural dynamics applications. The resulting tools have been demonstrated on large problems representative of a weapon's system.

  13. Genetic algorithm based task reordering to improve the performance of batch scheduled massively parallel scientific applications

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sankaran, Ramanan; Angel, Jordan; Brown, W. Michael

    2015-04-08

    The growth in size of networked high performance computers along with novel accelerator-based node architectures has further emphasized the importance of communication efficiency in high performance computing. The world's largest high performance computers are usually operated as shared user facilities due to the costs of acquisition and operation. Applications are scheduled for execution in a shared environment and are placed on nodes that are not necessarily contiguous on the interconnect. Furthermore, the placement of tasks on the nodes allocated by the scheduler is sub-optimal, leading to performance loss and variability. Here, we investigate the impact of task placement on themore »performance of two massively parallel application codes on the Titan supercomputer, a turbulent combustion flow solver (S3D) and a molecular dynamics code (LAMMPS). Benchmark studies show a significant deviation from ideal weak scaling and variability in performance. The inter-task communication distance was determined to be one of the significant contributors to the performance degradation and variability. A genetic algorithm-based parallel optimization technique was used to optimize the task ordering. This technique provides an improved placement of the tasks on the nodes, taking into account the application's communication topology and the system interconnect topology. As a result, application benchmarks after task reordering through genetic algorithm show a significant improvement in performance and reduction in variability, therefore enabling the applications to achieve better time to solution and scalability on Titan during production.« less

  14. System and method for representing and manipulating three-dimensional objects on massively parallel architectures

    DOE Patents [OSTI]

    Karasick, M.S.; Strip, D.R.

    1996-01-30

    A parallel computing system is described that comprises a plurality of uniquely labeled, parallel processors, each processor capable of modeling a three-dimensional object that includes a plurality of vertices, faces and edges. The system comprises a front-end processor for issuing a modeling command to the parallel processors, relating to a three-dimensional object. Each parallel processor, in response to the command and through the use of its own unique label, creates a directed-edge (d-edge) data structure that uniquely relates an edge of the three-dimensional object to one face of the object. Each d-edge data structure at least includes vertex descriptions of the edge and a description of the one face. As a result, each processor, in response to the modeling command, operates upon a small component of the model and generates results, in parallel with all other processors, without the need for processor-to-processor intercommunication. 8 figs.

  15. System and method for representing and manipulating three-dimensional objects on massively parallel architectures

    DOE Patents [OSTI]

    Karasick, Michael S. (Ridgefield, CT); Strip, David R. (Albuquerque, NM)

    1996-01-01

    A parallel computing system is described that comprises a plurality of uniquely labeled, parallel processors, each processor capable of modelling a three-dimensional object that includes a plurality of vertices, faces and edges. The system comprises a front-end processor for issuing a modelling command to the parallel processors, relating to a three-dimensional object. Each parallel processor, in response to the command and through the use of its own unique label, creates a directed-edge (d-edge) data structure that uniquely relates an edge of the three-dimensional object to one face of the object. Each d-edge data structure at least includes vertex descriptions of the edge and a description of the one face. As a result, each processor, in response to the modelling command, operates upon a small component of the model and generates results, in parallel with all other processors, without the need for processor-to-processor intercommunication.

  16. Massively parallel algorithms for method of characteristics neutral particle transport on shared memory computer architectures

    E-Print Network [OSTI]

    Boyd, William Robert Dawson, III

    2014-01-01

    Over the past 20 years, parallel computing has enabled computers to grow ever larger and more powerful while scientific applications have advanced in sophistication and resolution. This trend is being challenged, however, ...

  17. On the Kinematics of Solar Mirrors Using Massively Parallel Binary Actuation

    E-Print Network [OSTI]

    Dubowsky, Steven

    Precision mirrors are required for effective solar energy collectors. Manufacturing such mirrors and making them robust to disturbances such as thermal gradients is expensive. In this paper, the use of parallel binary ...

  18. Massively parallel implementation of the multi-reference Brillouin-Wigner CCSD method

    SciTech Connect (OSTI)

    Brabec, Jiri; Krishnamoorthy, Sriram; van Dam, Hubertus JJ; Kowalski, Karol; Pittner, Jiri

    2011-10-06

    This paper reports the parallel implementation of the Brillouin Wigner MultiReference Coupled Cluster method with Single and Double excitations (BW-MRCCSD). Preliminary tests for systems composed of 304 and 440 correlated obritals demonstrate the performance of our implementation across 1000 cores and clearly indicate the advantages of using improved task scheduling. Possible ways for further improvements of the parallel performance are also delineated.

  19. Massively parallel processing on the Intel Paragon system: One tool in achieving the goals of the Human Genome Project

    SciTech Connect (OSTI)

    Ecklund, D.J.

    1993-12-31

    A massively parallel computing system is one tool that has been adopted by researchers in the Human Genome Project. This tool is one of many in a toolbox of theories, algorithms, and systems that are used to attack the many questions posed by the project. A good tool functions well when applied alone to the problem for which it was devised. A superior tool achieves its solitary goal, and supports and interacts with other tools to achieve goals beyond the scope of any individual tool. The author believes that Intel`s massively parallel Paragon{trademark} XP/S system is a superior tool. This paper presents specific requirements for a superior computing tool for the Human Genome Project (HGP) and shows how the Paragon system addresses these requirements. Computing requirements for HGP are based on three factors: (1) computing requirements of algorithms currently used in sequence homology, protein folding, and database insertion/retrieval; (2) estimates of the computing requirements of new applications arising from evolving biological theories; and (3) the requirements for facilities that support collaboration among scientists in a project of this magnitude. The Paragon system provides many hardware and software features that effectively address these requirements.

  20. Massively-parallel Spectral Element Algorithm Development for High Speed Flows 

    E-Print Network [OSTI]

    Camp, Joshua Lane

    2013-10-07

    struggle (an example of this being combustor flows). A relatively recent compromise between the stringent requirement of DNS and the reduced accuracy of RANS is large-eddy simulation, or LES. Although many variants exist, a common approach among LES models... million processes with a parallel efficiency of over 60% [10]. Using NEK5000, our group has simulated several gas turbine components using LES and DNS, including a high pressure turbine blade [14], low pressure turbine blade [15], and cold flow combustor...

  1. Massively-parallel electron dynamics calculations in real-time and real-space: Toward applications to nanostructures of more than ten-nanometers in size

    SciTech Connect (OSTI)

    Noda, Masashi; Ishimura, Kazuya; Nobusada, Katsuyuki [Institute for Molecular Science, Myodaiji, Okazaki, Aichi 444-8585 (Japan); Yabana, Kazuhiro; Boku, Taisuke [Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)

    2014-05-15

    A highly efficient program of massively parallel calculations for electron dynamics has been developed in an effort to apply the method to optical response of nanostructures of more than ten-nanometers in size. The approach is based on time-dependent density functional theory calculations in real-time and real-space. The computational code is implemented by using simple algorithms with a finite-difference method in space derivative and Taylor expansion in time-propagation. Since the computational program is free from the algorithms of eigenvalue problems and fast-Fourier-transformation, which are usually implemented in conventional quantum chemistry or band structure calculations, it is highly suitable for massively parallel calculations. Benchmark calculations using the K computer at RIKEN demonstrate that the parallel efficiency of the program is very high on more than 60?000 CPU cores. The method is applied to optical response of arrays of C{sub 60} orderly nanostructures of more than 10 nm in size. The computed absorption spectrum is in good agreement with the experimental observation.

  2. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by dynamically adjusting local routing strategies

    DOE Patents [OSTI]

    Archer, Charles Jens (Rochester, MN); Musselman, Roy Glenn (Rochester, MN); Peters, Amanda (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Swartz, Brent Allen (Chippewa Falls, WI); Wallenfelt, Brian Paul (Eden Prairie, MN)

    2010-03-16

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. Each node implements a respective routing strategy for routing data through the network, the routing strategies not necessarily being the same in every node. The routing strategies implemented in the nodes are dynamically adjusted during application execution to shift network workload as required. Preferably, adjustment of routing policies in selective nodes is performed at synchronization points. The network may be dynamically monitored, and routing strategies adjusted according to detected network conditions.

  3. Method and apparatus for analyzing error conditions in a massively parallel computer system by identifying anomalous nodes within a communicator set

    DOE Patents [OSTI]

    Gooding, Thomas Michael (Rochester, MN)

    2011-04-19

    An analytical mechanism for a massively parallel computer system automatically analyzes data retrieved from the system, and identifies nodes which exhibit anomalous behavior in comparison to their immediate neighbors. Preferably, anomalous behavior is determined by comparing call-return stack tracebacks for each node, grouping like nodes together, and identifying neighboring nodes which do not themselves belong to the group. A node, not itself in the group, having a large number of neighbors in the group, is a likely locality of error. The analyzer preferably presents this information to the user by sorting the neighbors according to number of adjoining members of the group.

  4. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by routing through transporter nodes

    DOE Patents [OSTI]

    Archer, Charles Jens (Rochester, MN); Musselman, Roy Glenn (Rochester, MN); Peters, Amanda (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Swartz, Brent Allen (Chippewa Falls, WI); Wallenfelt, Brian Paul (Eden Prairie, MN)

    2010-11-16

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. An automated routing strategy routes packets through one or more intermediate nodes of the network to reach a destination. Some packets are constrained to be routed through respective designated transporter nodes, the automated routing strategy determining a path from a respective source node to a respective transporter node, and from a respective transporter node to a respective destination node. Preferably, the source node chooses a routing policy from among multiple possible choices, and that policy is followed by all intermediate nodes. The use of transporter nodes allows greater flexibility in routing.

  5. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by employing bandwidth shells at areas of overutilization

    DOE Patents [OSTI]

    Archer, Charles Jens; Musselman, Roy Glenn; Peters, Amanda; Pinnow, Kurt Walter; Swartz, Brent Allen; Wallenfelt, Brian Paul

    2010-04-27

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. An automated routing strategy routes packets through one or more intermediate nodes of the network to reach a final destination. The default routing strategy is altered responsive to detection of overutilization of a particular path of one or more links, and at least some traffic is re-routed by distributing the traffic among multiple paths (which may include the default path). An alternative path may require a greater number of link traversals to reach the destination node.

  6. CX-001635: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Solar American Institute Incubator - Semprius - Massively Parallel Microcell-Based Module ArrayCX(s) Applied: B3.6Date: 04/08/2010Location(s): Durham, North CarolinaOffice(s): Energy Efficiency and Renewable Energy, Golden Field Office

  7. User's guide of TOUGH2-EGS-MP: A Massively Parallel Simulator with Coupled Geomechanics for Fluid and Heat Flow in Enhanced Geothermal Systems VERSION 1.0

    SciTech Connect (OSTI)

    Xiong, Yi; Fakcharoenphol, Perapon; Wang, Shihao; Winterfeld, Philip H.; Zhang, Keni; Wu, Yu-Shu

    2013-12-01

    TOUGH2-EGS-MP is a parallel numerical simulation program coupling geomechanics with fluid and heat flow in fractured and porous media, and is applicable for simulation of enhanced geothermal systems (EGS). TOUGH2-EGS-MP is based on the TOUGH2-MP code, the massively parallel version of TOUGH2. In TOUGH2-EGS-MP, the fully-coupled flow-geomechanics model is developed from linear elastic theory for thermo-poro-elastic systems and is formulated in terms of mean normal stress as well as pore pressure and temperature. Reservoir rock properties such as porosity and permeability depend on rock deformation, and the relationships between these two, obtained from poro-elasticity theories and empirical correlations, are incorporated into the simulation. This report provides the user with detailed information on the TOUGH2-EGS-MP mathematical model and instructions for using it for Thermal-Hydrological-Mechanical (THM) simulations. The mathematical model includes the fluid and heat flow equations, geomechanical equation, and discretization of those equations. In addition, the parallel aspects of the code, such as domain partitioning and communication between processors, are also included. Although TOUGH2-EGS-MP has the capability for simulating fluid and heat flows coupled with geomechanical effects, it is up to the user to select the specific coupling process, such as THM or only TH, in a simulation. There are several example problems illustrating applications of this program. These example problems are described in detail and their input data are presented. Their results demonstrate that this program can be used for field-scale geothermal reservoir simulation in porous and fractured media with fluid and heat flow coupled with geomechanical effects.

  8. Parallel Processing of Large Datasets from NanoLC-FTICR-MS Measurements

    E-Print Network [OSTI]

    van Nieuwpoort, Rob V.

    with the massively parallel processing approach described here allows the scientist to reprocess data

  9. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by semi-randomly varying routing policies for different packets

    DOE Patents [OSTI]

    Archer, Charles Jens (Rochester, MN); Musselman, Roy Glenn (Rochester, MN); Peters, Amanda (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Swartz, Brent Allen (Chippewa Falls, WI); Wallenfelt, Brian Paul (Eden Prairie, MN)

    2010-11-23

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. Nodes vary a choice of routing policy for routing data in the network in a semi-random manner, so that similarly situated packets are not always routed along the same path. Semi-random variation of the routing policy tends to avoid certain local hot spots of network activity, which might otherwise arise using more consistent routing determinations. Preferably, the originating node chooses a routing policy for a packet, and all intermediate nodes in the path route the packet according to that policy. Policies may be rotated on a round-robin basis, selected by generating a random number, or otherwise varied.

  10. Parallel computing works

    SciTech Connect (OSTI)

    Not Available

    1991-10-23

    An account of the Caltech Concurrent Computation Program (C{sup 3}P), a five year project that focused on answering the question: Can parallel computers be used to do large-scale scientific computations '' As the title indicates, the question is answered in the affirmative, by implementing numerous scientific applications on real parallel computers and doing computations that produced new scientific results. In the process of doing so, C{sup 3}P helped design and build several new computers, designed and implemented basic system software, developed algorithms for frequently used mathematical computations on massively parallel machines, devised performance models and measured the performance of many computers, and created a high performance computing facility based exclusively on parallel computers. While the initial focus of C{sup 3}P was the hypercube architecture developed by C. Seitz, many of the methods developed and lessons learned have been applied successfully on other massively parallel architectures.

  11. High-speed massively parallel scanning

    DOE Patents [OSTI]

    Decker, Derek E. (Byron, CA)

    2010-07-06

    A new technique for recording a series of images of a high-speed event (such as, but not limited to: ballistics, explosives, laser induced changes in materials, etc.) is presented. Such technique(s) makes use of a lenslet array to take image picture elements (pixels) and concentrate light from each pixel into a spot that is much smaller than the pixel. This array of spots illuminates a detector region (e.g., film, as one embodiment) which is scanned transverse to the light, creating tracks of exposed regions. Each track is a time history of the light intensity for a single pixel. By appropriately configuring the array of concentrated spots with respect to the scanning direction of the detection material, different tracks fit between pixels and sufficient lengths are possible which can be of interest in several high-speed imaging applications.

  12. Massively Parallel Computing: Unstructured Finite Element Simulations

    E-Print Network [OSTI]

    Johnsson, S. Lennart

    of NAFEM 4th International Conference on Quality Assurance and Standards in Finite Element and Associated

  13. Massive Orbifold

    E-Print Network [OSTI]

    S. Cecotti; C. Vafa

    1992-03-24

    We study some aspects of 2d supersymmetric sigma models on orbifolds. It turns out that independently of whether the 2d QFT is conformal the operator products of twist operators are non-singular, suggesting that massive (non-conformal) orbifolds also `resolve singularities' just as in the conformal case. Moreover we recover the OPE of twist operators for conformal theories by considering the UV limit of the massive orbifold correlation functions. Alternatively, we can use the OPE of twist fields at the conformal point to derive conditions for the existence of non-singular solutions to special non-linear differential equations (such as Painleve III).

  14. Parallel Communicating Grammar Systems Lila Santean

    E-Print Network [OSTI]

    Kari, Lila

    Parallel Communicating Grammar Systems Lila Santean Academy of Finland and Mathematics Department of massively parallel processing systems increased the importance of interprocessor communication in the new of modelling the process of communication [2]. They consist of a system of grammars working together to produce

  15. Ultrascalable petaflop parallel supercomputer

    DOE Patents [OSTI]

    Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton On Hudson, NY); Chiu, George (Cross River, NY); Cipolla, Thomas M. (Katonah, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Hall, Shawn (Pleasantville, NY); Haring, Rudolf A. (Cortlandt Manor, NY); Heidelberger, Philip (Cortlandt Manor, NY); Kopcsay, Gerard V. (Yorktown Heights, NY); Ohmacht, Martin (Yorktown Heights, NY); Salapura, Valentina (Chappaqua, NY); Sugavanam, Krishnan (Mahopac, NY); Takken, Todd (Brewster, NY)

    2010-07-20

    A massively parallel supercomputer of petaOPS-scale includes node architectures based upon System-On-a-Chip technology, where each processing node comprises a single Application Specific Integrated Circuit (ASIC) having up to four processing elements. The ASIC nodes are interconnected by multiple independent networks that optimally maximize the throughput of packet communications between nodes with minimal latency. The multiple networks may include three high-speed networks for parallel algorithm message passing including a Torus, collective network, and a Global Asynchronous network that provides global barrier and notification functions. These multiple independent networks may be collaboratively or independently utilized according to the needs or phases of an algorithm for optimizing algorithm processing performance. The use of a DMA engine is provided to facilitate message passing among the nodes without the expenditure of processing resources at the node.

  16. Scheduling of real-time communication network for parallel processing 

    E-Print Network [OSTI]

    Li, Hung

    1995-01-01

    As real-time applications become more and more complicated their demands of processing capacity can hardly be satisfied. Massively parallel computers, such as Intel Paragon, with their scalable architecture and tremendous ...

  17. A Parallel 2D Operator Splitting Method for the Navier--Stokes and Transport Equations

    E-Print Network [OSTI]

    Cirpka, Olaf Arie

    areas on a 'multiple in-- struction multiple data' (MIMD) parallel computer with 128 processors--Zingster Boddenkette'. 1. INTRODUCTION In recent years the use of massively parallel computer systems for large scale computers, especially when problems such as solving large sets of equations are dealt with. A MIMD parallel

  18. Massively Parallel Asset and Liability Andreas Grothey1

    E-Print Network [OSTI]

    Grothey, Andreas

    (in particular Interior Point Methods) and the use of High Performance Computing techniques have made measures can be integrated into the framework and address the issue of modelling for High Performance Computing. 1 Introduction Asset and Liability Management (ALM) is one of the most important applica- tions

  19. Massively parallel simulation of cardiac electrical wave propagation ...

    E-Print Network [OSTI]

    2007-10-30

    standing of cardiac electrical properties. Conducting detailed, large-scale simulations of the cardiac electrical activity presents several challenges: the heart has ...

  20. Mapping the Hallmarks of Lung Adenocarcinoma with Massively Parallel Sequencing

    E-Print Network [OSTI]

    Lander, Eric S.

    Lung adenocarcinoma, the most common subtype of non-small cell lung cancer, is responsible for more than 500,000 deaths per year worldwide. Here, we report exome and genome sequences of 183 lung adenocarcinoma tumor/normal ...

  1. Massively parallel structured direct solver for equations describing ...

    E-Print Network [OSTI]

    2011-10-17

    need for the introduction of coupled systems of partial differential equations to lower ... complexity and interprocessor communication estimates of our algorithm.

  2. Practical realization of massively parallel fiberfree-space optical interconnects

    E-Print Network [OSTI]

    Jahns, Jürgen

    on a computer-controlled milling machine. Channel densities are of the order of 100 mm2 between optoelectronic

  3. I High-Performance I/O for Massively Parallel

    E-Print Network [OSTI]

    levels of clarity and detail in areas such as climate prediction and control, air and water pollution and test of anticancer agents, anti-AIDS drugs, aircraft wingfoils, modern combustion engines, oil-performance aircraft simulation Computational fluid and combustion dynamics 4 Gbytes of data/4 hrs. 40 Mbytes to 2 GBps

  4. Discontinuous Methods for Accurate, Massively Parallel Quantum Molecular

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HAB PacketDiesel pricesCenter atDirectory Searchable directory.

  5. Planets Around Massive Subgiants

    E-Print Network [OSTI]

    John A. Johnson

    2007-10-16

    Compared to planets around Sun-like stars, relatively little is known about the occurrence rate and orbital properties of planets around stars more massive than 1.3 Msun. The apparent deficit of planets around massive stars is due to a strong selection bias against early-type dwarfs in Doppler-based planet searches. One method to circumvent the difficulties inherent to massive main-sequence stars is to instead observe them after they have evolved onto the subgiant branch. We show how the cooler atmospheres and slower rotation velocities of subgiants make them ideal proxies for F- and A-type stars. We present the early results from our planet search that reveal a paucity of planets orbiting within 1 AU of stars more massive than 1.5 Msun, and evidence of a rising trend in giant planet occurrence with stellar mass.

  6. Topological Massive Sigma Models

    E-Print Network [OSTI]

    N. D. Lambert

    1995-05-03

    In this paper we construct topological sigma models which include a potential and are related to twisted massive supersymmetric sigma models. Contrary to a previous construction these models have no central charge and do not require the manifold to admit a Killing vector. We use the topological massive sigma model constructed here to simplify the calculation of the observables. Lastly it is noted that this model can be viewed as interpolating between topological massless sigma models and topological Landau-Ginzburg models.

  7. A novel polymeric microelectrode array for highly parallel, long-term neuronal culture and stimulation

    E-Print Network [OSTI]

    Talei Franzesi, Giovanni

    2008-01-01

    Cell-based high-throughput screening is emerging as a disruptive technology in drug discovery; however, massively parallel electrical assaying of neurons and cardiomyocites has until now been prohibitively expensive. To ...

  8. Parallel MATLAB at VT: Parallel For Loops

    E-Print Network [OSTI]

    Crawford, T. Daniel

    discussed Matlab's Parallel Computing Toolbox (PCT), and the Distributed Computing Server (MDCS) that runs;FMINCON: Hidden Parallelism FMINCON is a popular Matlab function available in the Optimization Toolbox using FMINCON involves a boat trying to cross a river against a current. The boat is given 10 minutes

  9. Parallel Seismic Ray Tracing 

    E-Print Network [OSTI]

    Jain, Tarun K

    2013-12-09

    the idea of modeling ray tubes with an additional ray in the center to facilitate parallelism. The parallel wavefront construction algorithm is applied to wide range of models such as simple synthetic models that enable us to study various aspects...

  10. Parallel flow diffusion battery

    DOE Patents [OSTI]

    Yeh, H.C.; Cheng, Y.S.

    1984-01-01

    A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

  11. Parallel flow diffusion battery

    DOE Patents [OSTI]

    Yeh, Hsu-Chi (Albuquerque, NM); Cheng, Yung-Sung (Albuquerque, NM)

    1984-08-07

    A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

  12. Parallel Implementation of the PHOENIX Generalized Stellar Atmosphere Program. II: Wavelength Parallelization

    E-Print Network [OSTI]

    E. Baron; Peter H. Hauschildt

    1997-09-24

    We describe an important addition to the parallel implementation of our generalized NLTE stellar atmosphere and radiative transfer computer program PHOENIX. In a previous paper in this series we described data and task parallel algorithms we have developed for radiative transfer, spectral line opacity, and NLTE opacity and rate calculations. These algorithms divided the work spatially or by spectral lines, that is distributing the radial zones, individual spectral lines, or characteristic rays among different processors and employ, in addition task parallelism for logically independent functions (such as atomic and molecular line opacities). For finite, monotonic velocity fields, the radiative transfer equation is an initial value problem in wavelength, and hence each wavelength point depends upon the previous one. However, for sophisticated NLTE models of both static and moving atmospheres needed to accurately describe, e.g., novae and supernovae, the number of wavelength points is very large (200,000--300,000) and hence parallelization over wavelength can lead both to considerable speedup in calculation time and the ability to make use of the aggregate memory available on massively parallel supercomputers. Here, we describe an implementation of a pipelined design for the wavelength parallelization of PHOENIX, where the necessary data from the processor working on a previous wavelength point is sent to the processor working on the succeeding wavelength point as soon as it is known. Our implementation uses a MIMD design based on a relatively small number of standard MPI library calls and is fully portable between serial and parallel computers.

  13. The STAPL Parallel Container Framework 

    E-Print Network [OSTI]

    Tanase, Ilie Gabriel

    2012-02-14

    The Standard Template Adaptive Parallel Library (STAPL) is a parallel programming infrastructure that extends C with support for parallelism. STAPL provides a run-time system, a collection of distributed data structures (pContainers) and parallel...

  14. Parallel integrated thermal management

    DOE Patents [OSTI]

    Bennion, Kevin; Thornton, Matthew

    2014-08-19

    Embodiments discussed herein are directed to managing the heat content of two vehicle subsystems through a single coolant loop having parallel branches for each subsystem.

  15. Magnetic fields in massive stars

    E-Print Network [OSTI]

    S. Hubrig; M. Schoeller; M. Briquet; M. A. Pogodin; R. V. Yudin; J. F. Gonzalez; T. Morel; P. De Cat; R. Ignace; P. North; G. Mathys; G. J. Peters

    2007-12-02

    We review the recent discoveries of magnetic fields in different types of massive stars and briefly discuss strategies for spectropolarimetric observations to be carried out in the future.

  16. Magnetic fields in massive stars

    E-Print Network [OSTI]

    Hubrig, S; Briquet, M; Pogodin, M A; Yudin, R V; González, J F; Morel, T; De Cat, P; Ignace, R; North, P; Mathys, G; Peters, G J

    2007-01-01

    We review the recent discoveries of magnetic fields in different types of massive stars and briefly discuss strategies for spectropolarimetric observations to be carried out in the future.

  17. Massive neutrinos and cosmology

    E-Print Network [OSTI]

    Julien Lesgourgues; Sergio Pastor

    2006-05-29

    The present experimental results on neutrino flavour oscillations provide evidence for non-zero neutrino masses, but give no hint on their absolute mass scale, which is the target of beta decay and neutrinoless double-beta decay experiments. Crucial complementary information on neutrino masses can be obtained from the analysis of data on cosmological observables, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure. In this review we describe in detail how free-streaming massive neutrinos affect the evolution of cosmological perturbations. We summarize the current bounds on the sum of neutrino masses that can be derived from various combinations of cosmological data, including the most recent analysis by the WMAP team. We also discuss how future cosmological experiments are expected to be sensitive to neutrino masses well into the sub-eV range.

  18. An efficient parallel algorithm for matrix-vector multiplication

    SciTech Connect (OSTI)

    Hendrickson, B.; Leland, R.; Plimpton, S.

    1993-03-01

    The multiplication of a vector by a matrix is the kernel computation of many algorithms in scientific computation. A fast parallel algorithm for this calculation is therefore necessary if one is to make full use of the new generation of parallel supercomputers. This paper presents a high performance, parallel matrix-vector multiplication algorithm that is particularly well suited to hypercube multiprocessors. For an n x n matrix on p processors, the communication cost of this algorithm is O(n/[radical]p + log(p)), independent of the matrix sparsity pattern. The performance of the algorithm is demonstrated by employing it as the kernel in the well-known NAS conjugate gradient benchmark, where a run time of 6.09 seconds was observed. This is the best published performance on this benchmark achieved to date using a massively parallel supercomputer.

  19. Large-Scale Molecular Dynamics Simulations for Highly Parallel Infrastructures

    E-Print Network [OSTI]

    Pazúriková, Jana

    2014-01-01

    Computational chemistry allows researchers to experiment in sillico: by running a computer simulations of a biological or chemical processes of interest. Molecular dynamics with molecular mechanics model of interactions simulates N-body problem of atoms$-$it computes movements of atoms according to Newtonian physics and empirical descriptions of atomic electrostatic interactions. These simulations require high performance computing resources, as evaluations within each step are computationally demanding and billions of steps are needed to reach interesting timescales. Current methods decompose the spatial domain of the problem and calculate on parallel/distributed infrastructures. Even the methods with the highest strong scaling hit the limit at half a million cores: they are not able to cut the time to result if provided with more processors. At the dawn of exascale computing with massively parallel computational resources, we want to increase the level of parallelism by incorporating parallel-in-time comput...

  20. Superconnections and Parallel Transport

    E-Print Network [OSTI]

    Dumitrescu, Florin

    2007-01-01

    This note addresses the construction of a notion of parallel transport along superpaths arising from the concept of a superconnection on a vector bundle over a manifold $M$. A superpath in $M$ is, loosely speaking, a path in $M$ together with an odd vector field in $M$ along the path. We also develop a notion of parallel transport associated with a connection (a.k.a. covariant derivative) on a vector bundle over a \\emph{supermanifold} which is a direct generalization of the classical notion of parallel transport for connections over manifolds.

  1. Massive Datasets in Astronomy

    E-Print Network [OSTI]

    Robert J. Brunner; S. George Djorgovski; Thomas A. Prince; Alex S. Szalay

    2001-06-26

    Astronomy has a long history of acquiring, systematizing, and interpreting large quantities of data. Starting from the earliest sky atlases through the first major photographic sky surveys of the 20th century, this tradition is continuing today, and at an ever increasing rate. Like many other fields, astronomy has become a very data-rich science, driven by the advances in telescope, detector, and computer technology. Numerous large digital sky surveys and archives already exist, with information content measured in multiple Terabytes, and even larger, multi-Petabyte data sets are on the horizon. Systematic observations of the sky, over a range of wavelengths, are becoming the primary source of astronomical data. Numerical simulations are also producing comparable volumes of information. Data mining promises to both make the scientific utilization of these data sets more effective and more complete, and to open completely new avenues of astronomical research. Technological problems range from the issues of database design and federation, to data mining and advanced visualization, leading to a new toolkit for astronomical research. This is similar to challenges encountered in other data-intensive fields today. These advances are now being organized through a concept of the Virtual Observatories, federations of data archives and services representing a new information infrastructure for astronomy of the 21st century. In this article, we provide an overview of some of the major datasets in astronomy, discuss different techniques used for archiving data, and conclude with a discussion of the future of massive datasets in astronomy.

  2. Electromagnetic properties of massive neutrinos

    SciTech Connect (OSTI)

    Dobrynina, A. A., E-mail: aleksandradobrynina@rambler.ru; Mikheev, N. V.; Narynskaya, E. N. [Demidov Yaroslavl State University (Russian Federation)] [Demidov Yaroslavl State University (Russian Federation)

    2013-10-15

    The vertex function for a virtual massive neutrino is calculated in the limit of soft real photons. A method based on employing the neutrino self-energy operator in a weak external electromagnetic field in the approximation linear in the field is developed in order to render this calculation of the vertex function convenient. It is shown that the electric charge and the electric dipole moment of the real neutrino are zero; only the magnetic moment is nonzero for massive neutrinos. A fourth-generation heavy neutrino of mass not less than half of the Z-boson mass is considered as a massive neutrino.

  3. Thought Leaders during Crises in Massive Social Networks

    SciTech Connect (OSTI)

    Corley, Courtney D.; Farber, Robert M.; Reynolds, William

    2012-05-24

    The vast amount of social media data that can be gathered from the internet coupled with workflows that utilize both commodity systems and massively parallel supercomputers, such as the Cray XMT, open new vistas for research to support health, defense, and national security. Computer technology now enables the analysis of graph structures containing more than 4 billion vertices joined by 34 billion edges along with metrics and massively parallel algorithms that exhibit near-linear scalability according to number of processors. The challenge lies in making this massive data and analysis comprehensible to an analyst and end-users that require actionable knowledge to carry out their duties. Simply stated, we have developed language and content agnostic techniques to reduce large graphs built from vast media corpora into forms people can understand. Specifically, our tools and metrics act as a survey tool to identify thought leaders' -- those members that lead or reflect the thoughts and opinions of an online community, independent of the source language.

  4. Massive gravity from bimetric gravity

    E-Print Network [OSTI]

    Baccetti, Valentina; Visser, Matt

    2012-01-01

    We discuss the subtle relationship between so-called massive gravity (that is, gravity incorporating a non-zero graviton mass) and bimetric gravity, focussing particularly on the manner in which massive gravity may be viewed as a suitable limit of bimetric gravity. The limiting procedure is more delicate than currently appreciated, and in particular, in a cosmological context can lead to an interesting interplay between the "background" and "foreground" metrics. The fact that in bimetric theories one always has two sets of metric equations of motion, one for each metric, continues to have an effect even in the massive gravity limit. Thus, solutions of bimetric gravity in the limit of vanishing kinetic term are also solutions of massive gravity, but the contrary statement is not necessarily true.

  5. Parallel optical sampler

    DOE Patents [OSTI]

    Tauke-Pedretti, Anna; Skogen, Erik J; Vawter, Gregory A

    2014-05-20

    An optical sampler includes a first and second 1.times.n optical beam splitters splitting an input optical sampling signal and an optical analog input signal into n parallel channels, respectively, a plurality of optical delay elements providing n parallel delayed input optical sampling signals, n photodiodes converting the n parallel optical analog input signals into n respective electrical output signals, and n optical modulators modulating the input optical sampling signal or the optical analog input signal by the respective electrical output signals, and providing n successive optical samples of the optical analog input signal. A plurality of output photodiodes and eADCs convert the n successive optical samples to n successive digital samples. The optical modulator may be a photodiode interconnected Mach-Zehnder Modulator. A method of sampling the optical analog input signal is disclosed.

  6. Parallel programming with Ada

    SciTech Connect (OSTI)

    Kok, J.

    1988-01-01

    To the human programmer the ease of coding distributed computing is highly dependent on the suitability of the employed programming language. But with a particular language it is also important whether the possibilities of one or more parallel architectures can efficiently be addressed by available language constructs. In this paper the possibilities are discussed of the high-level language Ada and in particular of its tasking concept as a descriptional tool for the design and implementation of numerical and other algorithms that allow execution of parts in parallel. Language tools are explained and their use for common applications is shown. Conclusions are drawn about the usefulness of several Ada concepts.

  7. Parallel programming with PCN

    SciTech Connect (OSTI)

    Foster, I.; Tuecke, S.

    1993-01-01

    PCN is a system for developing and executing parallel programs. It comprises a high-level programming language, tools for developing and debugging programs in this language, and interfaces to Fortran and Cthat allow the reuse of existing code in multilingual parallel programs. Programs developed using PCN are portable across many different workstations, networks, and parallel computers. This document provides all the information required to develop parallel programs with the PCN programming system. It includes both tutorial and reference material. It also presents the basic concepts that underlie PCN, particularly where these are likely to be unfamiliar to the reader, and provides pointers to other documentation on the PCN language, programming techniques, and tools. PCN is in the public domain. The latest version of both the software and this manual can be obtained by anonymous ftp from Argonne National Laboratory in the directory pub/pcn at info.mcs. ani.gov (cf. Appendix A). This version of this document describes PCN version 2.0, a major revision of the PCN programming system. It supersedes earlier versions of this report.

  8. Learning in Parallel

    E-Print Network [OSTI]

    Vitter, Jeffrey Scott; Lin, Jyh-Han

    1992-01-01

    In this paper, we extend Valiant's sequential model of concept learning from examples [Valiant 1984] and introduce models for the e cient learning of concept classes from examples in parallel. We say that a concept class is NC-learnable if it can...

  9. Allinea DDT as a Parallel Debugging Alternative to Totalview

    SciTech Connect (OSTI)

    Antypas, K.B.

    2007-03-05

    Totalview, from the Etnus Corporation, is a sophisticated and feature rich software debugger for parallel applications. As Totalview has gained in popularity and market share its pricing model has increased to the point where it is often prohibitively expensive for massively parallel supercomputers. Additionally, many of Totalview's advanced features are not used by members of the scientific computing community. For these reasons, supercomputing centers have begun to search for a basic parallel debugging tool which can be used as an alternative to Totalview. As the cost and complexity of Totalview has increased over the years, scientific computing centers have started searching for a viable parallel debugging alternative. DDT (Distributed Debugging Tool) from Allinea Software is a relatively new parallel debugging tool which aims to provide much of the same functionality as Totalview. This review outlines the basic features and limitations of DDT to determine if it can be a reasonable substitute for Totalview. DDT was tested on the NERSC platforms Bassi, Seaborg, Jacquard and Davinci with Fortran90, C, and C++ codes using MPI and OpenMP for parallelism.

  10. Massive photons and Lorentz violation

    E-Print Network [OSTI]

    Mauro Cambiaso; Ralf Lehnert; Robertus Potting

    2012-01-14

    All quadratic translation- and gauge-invariant photon operators for Lorentz breakdown are included into the Stueckelberg Lagrangian for massive photons in a generalized \\xi-gauge. The corresponding dispersion relation and tree-level propagator are determined exactly, and some leading-order results are derived. The question of how to include such Lorentz-violating effects into a perturbative quantum-field expansion is addressed. Applications of these results within Lorentz-breaking quantum field theories include the regularization of infrared divergences as well as the free propagation of massive vector bosons.

  11. Massive Hybrid Stars with Strangeness

    E-Print Network [OSTI]

    Tatsuyuki Takatsuka; Tetsuo Hatsuda; Kota Masuda

    2014-02-19

    How massive the hybrid stars could be is discussed by a "3-window model" proposed from a new strategy to construct the equation of state with hadron-quark transition. It is found that hybrid stars have a strong potentiality to generate a large mass compatible with two-solar-mass neutron star observations.

  12. On parallel machine scheduling 1

    E-Print Network [OSTI]

    Magdeburg, Universität

    On parallel machine scheduling 1 machines with setup times. The setup has to be performed by a single server. The objective is to minimize even for the case of two identical parallel machines. This paper presents a pseudopolynomial

  13. Standard Templates Adaptive Parallel Library 

    E-Print Network [OSTI]

    Arzu, Francisco Jose

    2000-01-01

    STAPL (Standard Templates Adaptive Parallel Library) is a parallel C++ library designed as a superset of the C++ Standard Template Library (STL), sequentially consistent for functions with the same name, and executed on uni- or multi- processor...

  14. Practical Structured Parallelism using BMF 

    E-Print Network [OSTI]

    Crooke, David

    This thesis concerns the use of the Bird- Meertens Formalism as a mechanism to control parallelism in an imperative programming language. One of the main reasons for the failure of parallelism to enter mainstream computing ...

  15. Descriptive Simplicity in Parallel Computing 

    E-Print Network [OSTI]

    Marr, Marcus

    The programming of parallel computers is recognised as being a difficult task and there exist a wide selection of parallel programming languages and environments. This thesis presents and examines the Hierarchical ...

  16. Parallel Transports in Webs

    E-Print Network [OSTI]

    Christian Fleischhack

    2003-07-17

    For connected reductive linear algebraic structure groups it is proven that every web is holonomically isolated. The possible tuples of parallel transports in a web form a Lie subgroup of the corresponding power of the structure group. This Lie subgroup is explicitly calculated and turns out to be independent of the chosen local trivializations. Moreover, explicit necessary and sufficient criteria for the holonomical independence of webs are derived. The results above can even be sharpened: Given an arbitrary neighbourhood of the base points of a web, then this neighbourhood contains some segments of the web whose parameter intervals coincide, but do not include 0 (that corresponds to the base points of the web), and whose parallel transports already form the same Lie subgroup as those of the full web do.

  17. Parallel grid population

    DOE Patents [OSTI]

    Wald, Ingo; Ize, Santiago

    2015-07-28

    Parallel population of a grid with a plurality of objects using a plurality of processors. One example embodiment is a method for parallel population of a grid with a plurality of objects using a plurality of processors. The method includes a first act of dividing a grid into n distinct grid portions, where n is the number of processors available for populating the grid. The method also includes acts of dividing a plurality of objects into n distinct sets of objects, assigning a distinct set of objects to each processor such that each processor determines by which distinct grid portion(s) each object in its distinct set of objects is at least partially bounded, and assigning a distinct grid portion to each processor such that each processor populates its distinct grid portion with any objects that were previously determined to be at least partially bounded by its distinct grid portion.

  18. Xyce parallel electronic simulator.

    SciTech Connect (OSTI)

    Keiter, Eric Richard; Mei, Ting; Russo, Thomas V.; Rankin, Eric Lamont; Schiek, Richard Louis; Thornquist, Heidi K.; Fixel, Deborah A.; Coffey, Todd Stirling; Pawlowski, Roger Patrick; Santarelli, Keith R.

    2010-05-01

    This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users' Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users' Guide.

  19. Design and Implementation of a Parallel Heterogeneous Algorithm for Hyperspectral Image Analysis Using HeteroMPI

    E-Print Network [OSTI]

    Plaza, Antonio J.

    Design and Implementation of a Parallel Heterogeneous Algorithm for Hyperspectral Image Analysis The development of efficient techniques for transforming the massive volume of remotely sensed hyperspectral data a promising cost-effective solution expected to play a major role in many on-going and planned remote sensing

  20. Combining Strategies for Parallel Stochastic Approximation Monte Carlo Algorithm of Big Data 

    E-Print Network [OSTI]

    Lin, Fang-Yu

    2014-10-15

    Modeling and mining with massive volumes of data have become popular in recent decades. However, it is difficult to analyze on a single commodity computer because the size of data is too large. Parallel computing is widely used. As a natural...

  1. Improving Reliability of Energy-Efficient Parallel Storage Systems by Disk Swapping

    E-Print Network [OSTI]

    Qin, Xiao

    and the Massive Array of Idle Disks (MAID) technique are two effective energy saving schemes for parallel disk [2]. Existing energy conservation techniques can yield significant en- ergy savings in disks. While several energy conservation schemes like cache-based energy saving approaches normally have marginal

  2. New Parallel Randomized Algorithms for the Traveling Salesman Leyuan Shi 1 Sigurdur '

    E-Print Network [OSTI]

    Vázquez-Abad, Felisa J.

    it has many applications in such areas as routing robots through automatic warehouses and drilling holes way and it is highly matched to emerging massively parallel processing capabilities. In this paper, we method generates high quality solutions compared to well known heuristic methods and it can identify

  3. Computer Assisted Parallel Program Generation

    E-Print Network [OSTI]

    Kawata, Shigeo

    2015-01-01

    Parallel computation is widely employed in scientific researches, engineering activities and product development. Parallel program writing itself is not always a simple task depending on problems solved. Large-scale scientific computing, huge data analyses and precise visualizations, for example, would require parallel computations, and the parallel computing needs the parallelization techniques. In this Chapter a parallel program generation support is discussed, and a computer-assisted parallel program generation system P-NCAS is introduced. Computer assisted problem solving is one of key methods to promote innovations in science and engineering, and contributes to enrich our society and our life toward a programming-free environment in computing science. Problem solving environments (PSE) research activities had started to enhance the programming power in 1970's. The P-NCAS is one of the PSEs; The PSE concept provides an integrated human-friendly computational software and hardware system to solve a target ...

  4. New Branches of Massive Gravity

    E-Print Network [OSTI]

    Comelli, Denis; Koyama, Kazuya; Pilo, Luigi; Tasinato, Gianmassimo

    2015-01-01

    The basic building block for Lorentz invariant and ghost free massive gravity is the square root of the combination $g^{-1}\\eta\\,$, where $g^{-1}$ is the inverse of the physical metric and $\\eta$ is a reference metric. Since the square root of a matrix is not uniquely defined, it is possible to have physically inequivalent potentials corresponding to different branches. We show that around Minkowski background the only perturbatively well defined branch is the potential proposed by de Rham, Gabadadze and Tolley. On the other hand, if Lorentz symmetry is broken spontaneously, other potentials exist with a standard perturbative expansion. We show this explicitly building new Lorentz invariant, ghost-free massive gravity potentials for theories that in the background preserve rotational invariance, but break Lorentz boosts.

  5. Massive Photon and Dark Energy

    E-Print Network [OSTI]

    Kouwn, Seyen; Park, Chan-Gyung

    2015-01-01

    We investigate cosmology of massive electrodynamics and explore the possibility whether massive photon could provide an explanation of the dark energy. The action is given by the scalar-vector-tensor theory of gravity which is obtained by non-minimal coupling of the massive Stueckelberg QED with gravity and its cosmological consequences are studied by paying a particular attention to the role of photon mass. We find that the theory allows cosmological evolution where the radiation- and matter-dominated epochs are followed by a long period of virtually constant dark energy that closely mimics $\\Lambda$CDM model and the main source of the current acceleration is provided by the nonvanishing photon mass governed by the relation $\\Lambda\\sim m^2$. A detailed numerical analysis shows that the nonvanishing photon mass of the order of $\\sim 10^{-34}$ eV is consistent with the current observations. This magnitude is far less than the most stringent limit on the photon mass available so far, which is of the order of $...

  6. OSCAR Parallelizing Compiler and Its Performance for

    E-Print Network [OSTI]

    Kasahara, Hironori

    OSCAR Parallelizing Compiler and Its Performance for Embedded Applications Hironori Kasahara Supercomputers and servers Industry Capsule inner cameras Compiler, API Medical servers Heavy particle radiation productivity and reduce power OSCAR Parallelizing Compiler Multigrain Parallelization coarse-grain parallelism

  7. Parallel ptychographic reconstruction

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nashed, Youssef S. G.; Vine, David J.; Peterka, Tom; Deng, Junjing; Ross, Rob; Jacobsen, Chris

    2014-12-19

    Ptychography is an imaging method whereby a coherent beam is scanned across an object, and an image is obtained by iterative phasing of the set of diffraction patterns. It is able to be used to image extended objects at a resolution limited by scattering strength of the object and detector geometry, rather than at an optics-imposed limit. As technical advances allow larger fields to be imaged, computational challenges arise for reconstructing the correspondingly larger data volumes, yet at the same time there is also a need to deliver reconstructed images immediately so that one can evaluate the next steps tomore »take in an experiment. Here we present a parallel method for real-time ptychographic phase retrieval. It uses a hybrid parallel strategy to divide the computation between multiple graphics processing units (GPUs) and then employs novel techniques to merge sub-datasets into a single complex phase and amplitude image. Results are shown on a simulated specimen and a real dataset from an X-ray experiment conducted at a synchrotron light source.« less

  8. Parallel ptychographic reconstruction

    SciTech Connect (OSTI)

    Nashed, Youssef S. G.; Vine, David J.; Peterka, Tom; Deng, Junjing; Ross, Rob; Jacobsen, Chris

    2014-12-19

    Ptychography is an imaging method whereby a coherent beam is scanned across an object, and an image is obtained by iterative phasing of the set of diffraction patterns. It is able to be used to image extended objects at a resolution limited by scattering strength of the object and detector geometry, rather than at an optics-imposed limit. As technical advances allow larger fields to be imaged, computational challenges arise for reconstructing the correspondingly larger data volumes, yet at the same time there is also a need to deliver reconstructed images immediately so that one can evaluate the next steps to take in an experiment. Here we present a parallel method for real-time ptychographic phase retrieval. It uses a hybrid parallel strategy to divide the computation between multiple graphics processing units (GPUs) and then employs novel techniques to merge sub-datasets into a single complex phase and amplitude image. Results are shown on a simulated specimen and a real dataset from an X-ray experiment conducted at a synchrotron light source.

  9. Counterterms in Massive Gravity Theory

    E-Print Network [OSTI]

    Cao, Li-Ming

    2015-01-01

    We derived local boundary counterterms in massive gravity theory with a negative cosmological constant in four dimensions. With these counterterms at hand we analyzed the properties of the boundary field theory in the context of AdS/CFT duality by calculating the boundary stress energy tensor. The calculation shows that the boundary stress energy tensor is conserved, and momentum dissipation might occur on the level of linear response only. We also calculated the thermodynamic quantities and the boundary stress energy tensor for a specific type of solutions. The thermodynamic potentials agree with the results of literature up to some constants which can be removed by adding finite counterterms.

  10. 8/30/2001 Parallel Programming -Fall 2001 1 Models of Parallel Computation

    E-Print Network [OSTI]

    Browne, James C.

    8/30/2001 Parallel Programming - Fall 2001 1 Models of Parallel Computation Philosophy Parallel of parallel programming. #12;8/30/2001 Parallel Programming - Fall 2001 2 Models of Parallel Computation will discuss parallelism from the viewpoint of programming but with connections to other domains. #12;8/30/2001

  11. Solid Holography and Massive Gravity

    E-Print Network [OSTI]

    Alberte, Lasma; Khmelnitsky, Andrei; Pujolas, Oriol

    2015-01-01

    Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, this implies that the gravity dual is massive. We start here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and which, therefore, might store interesting condensed matter applications. We show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be clearly separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. We extract the modulus of rigidity of the solid HMG black brane solutions and show how it relates to the graviton mass term. We also consider the implications of the different HMGs on the electric...

  12. The evolution of very massive stars

    E-Print Network [OSTI]

    H. Belkus; J. Van Bever; D. Vanbeveren

    2007-01-11

    Core collapse of dense massive star clusters is unavoidable and this leads to the formation of massive objects, with a mass up to 1000 $\\msun$ and even larger. When these objects become stars, stellar wind mass loss determines their evolution and final fate, and decides upon whether they form black holes (with normal mass or with intermediate mass) or explode as a pair instability supernova. In the present paper, we discuss the evolution of very massive stars and we present a convenient evolution recipe that can be implemented in a gravitational N-body code to study the dynamics of dense massive clusters.

  13. MAGNETIC FIELD IN THE ISOLATED MASSIVE DENSE CLUMP IRAS 20126+4104

    SciTech Connect (OSTI)

    Shinnaga, Hiroko; Phillips, Thomas G. [California Institute of Technology Submillimeter Observatory, 111 Nowelo Street, Hilo, HI 96720 (United States); Novak, Giles [Department of Physics and Astronomy, Northwestern University, 633 Clark Street Evanston, IL 60208 (United States); Vaillancourt, John E. [Stratospheric Observatory for Infrared Astronomy, Universities Space Research Association, NASA Ames Research Center, Moffet Field, CA 94035 (United States); Machida, Masahiro N. [Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Kataoka, Akimasa [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Tomisaka, Kohji [National Astronomical Observatory of Japan and Department of Astronomy, School of Physical Sciences, Graduate University for Advanced Studies (SOKENDAI), Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Davidson, Jacqueline; Houde, Martin [School of Physics, University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth (Australia); Dowell, C. Darren [Jet Propulsion Laboratory, California Institute of Technology, MS 169-506, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Leeuw, Lerothodi [SETI Institute, 515 North Whisman Avenue, Mountain View, CA 94043 (United States)

    2012-05-10

    We measured polarized dust emission at 350 {mu}m toward the high-mass star-forming massive dense clump IRAS 20126+4104 using the SHARC II Polarimeter, SHARP, at the Caltech Submillimeter Observatory. Most of the observed magnetic field vectors agree well with magnetic field vectors obtained from a numerical simulation for the case when the global magnetic field lines are inclined with respect to the rotation axis of the dense clump. The results of the numerical simulation show that rotation plays an important role on the evolution of the massive dense clump and its magnetic field. The direction of the cold CO 1-0 bipolar outflow is parallel to the observed magnetic field within the dense clump as well as the global magnetic field, as inferred from optical polarimetry data, indicating that the magnetic field also plays a critical role in an early stage of massive star formation. The large-scale Keplerian disk of the massive (proto)star rotates in an almost opposite sense to the clump's envelope. The observed magnetic field morphology and the counterrotating feature of the massive dense clump system provide hints to constrain the role of magnetic fields in the process of high-mass star formation.

  14. Massive Variability Surveys from Venezuela

    E-Print Network [OSTI]

    Cesar Briceno

    2003-04-03

    At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

  15. Spin Operators for Massive Particles

    E-Print Network [OSTI]

    Taeseung Choi; Sam Young Cho

    2014-10-02

    How to define a proper relativistic spin operator, as a long-standing problem, has by now become a central task for providing proper concepts and applications of spin in relativistic and non-relativistic quantum mechanics as well as solving emergent inconsistencies in rapidly developing research areas. We rigorously {\\it derive} a relativistic spin operator for an arbitrary spin massive particle on the two requirements that a proper spin operator should satisfy (i) the $\\mathfrak{su}(2)$ algebra and (ii) the Lorentz-transformation properties as a second-rank spin tensor. These requirements lead to two spin operators, properly giving the second Casimir invariant operator in the Poincar\\'e (inhomogeneous Lorentz) group, that provide the two inequivalent representations of Poincar\\'e group. We find that the two inequivalent representations are the left-handed and the right-handed representations. Each of the two spin operators generates a Wigner little group whose representation space is composed of spin-$s$ spin states. In the case that the Poincar\\'e group is extended by parity, only nonchiral $(s,s)$ representations and direct-sum $(s,s') \\oplus (s',s)$ representations are allowed. In the $(1/2,0)\\oplus (0,1/2)$ representation, we redrive the covariant Dirac equation by using the covariant parity operator defined by the two spin operators. This derivation deepens our understanding how the Dirac equation describes the spin-$1/2$ massive relativistic particle successfully. We have also discussed some important properties of our relativistic spin operators with arbitrary spin.

  16. Parallel supercomputing: Advanced methods, algorithms and software for large-scale problems

    SciTech Connect (OSTI)

    Carey, G.F.; Young, D.M.

    1992-04-01

    Research has continued with excellent progress and new results on methodology and algorithms. We have also made supporting benchmark application studies on representative parallel computing architectures. Results from these research studies have been reported at scientific meetings, as technical reports and as journal publications. A list of pertinent presentations and publications is attached. The work on parallel element-by-element techniques and domain decomposition schemes has developed well. In particular, we have focused on the use of finite element spectral methods (or high p methods) on distributed massively parallel systems. The approach has been implemented in a prototype finite element program for solution of coupled Navier Stokes flow and transport processes. This class of problems is of fundamental interest and basic to many grand challenge'' type problems for which parallel supercomputing is warranted.

  17. Massively Deployed Sensors Final Project Report

    E-Print Network [OSTI]

    of massive deployment of sensors in electric power systems. There are several areas where the addition of modern, economical sensor technology can improve the quality of a large electric power grid. This reportMassively Deployed Sensors Final Project Report Power Systems Engineering Research Center

  18. On the Generator of Massive Modular Groups

    E-Print Network [OSTI]

    Timor Saffary

    2006-01-19

    The purpose of this paper is to shed more light on the transition from the known massless modular action to the wanted massive one in the case of forward light cones and double cones. The infinitesimal generator of the massive modular automorphism group is investigated, in particular, some assumptions on its structure are verified explicitly for two concrete examples.

  19. A Parallel Graph Partitioner for STAPL 

    E-Print Network [OSTI]

    Castet, Nicolas

    2013-04-26

    high-level framework to develop parallel applications. One of the first steps of a parallel application is to partition and distribute the data throughout the system. An important data structure for parallel applications to store large amounts of data...

  20. A Parallelized Hash Generator System

    E-Print Network [OSTI]

    EDA385 A Parallelized Hash Generator System Niklas Ald´en ael10nal@student.lu.se Gabriel J cracker uses the MD5 hash function to generate a hash from a random generated character sequence

  1. Parallel Programming and Optimization for Intel Architecture

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Parallel Programming and Optimization for Intel Architecture Parallel Programming and Optimization for Intel Architecture August 14, 2015 by Richard Gerber (0 Comments) Intel is...

  2. Massively-Parallel Direct Numerical Simulation of Gas Turbine Endwall Film-Cooling Conjugate Heat Transfer 

    E-Print Network [OSTI]

    Meador, Charles Michael

    2011-02-22

    Improvements to gas turbine efficiency depend closely on cooling technologies, as efficiency increases with turbine inlet temperature. To aid in this process, simulations that consider real engine conditions need to be ...

  3. Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer

    E-Print Network [OSTI]

    2008-01-01

    Research) since 1991, primarily in seismic interpretationand seismic attribute analysis. interpretation of CSEM data

  4. Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer

    E-Print Network [OSTI]

    2008-01-01

    areas of exploration geophysics including seismic imaging,seismic and electromagnetic modeling and inversion applied to hydrocarbon exploration.Seismic methods have a long and established history in hydrocarbon, i.e. oil and gas, exploration,

  5. Switching Dynamics of Thin Film Ferroelectric Devices- A Massively Parallel Phase Field Study

    E-Print Network [OSTI]

    Ashraf, Khalid

    2013-01-01

    charge. Magnetic devices Spintronic devices are one of theb) Magnetic tunnel junction. Spintronic devices are beingof magnetism Although spintronic devices are inherently low

  6. Evolution's footsteps : reconstructing in vitro and in vivo evolutionary trajectories via massively parallel sequencing and profiling

    E-Print Network [OSTI]

    Funt, Jason Michael

    2012-01-01

    Understanding how phenotypes evolve through natural selection is a fundamental question of biology. Microbial evolution studies provide the rare opportunity to experimentally elucidate the changes that allow an organism ...

  7. Massively-Parallel Spectral Element Large Eddy Simulation of a Ring-Type Gas Turbine Combustor 

    E-Print Network [OSTI]

    Camp, Joshua Lane

    2012-07-16

    The average and fluctuating components in a model ring-type gas turbine combustor are characterized using a Large Eddy Simulation at a Reynolds number of 11,000, based on the bulk velocity and the mean channel height. A spatial filter is applied...

  8. Massively parallel electrical conductivity imaging of the subsurface: Applications to hydrocarbon exploration

    E-Print Network [OSTI]

    Newman, G.A.

    2009-01-01

    d). Images are rendered in electrical conductivity.data in the presence of electrical anisotropy: submittedthe necessity to incorporate electrical anisotropy into the

  9. Massively parallel computing simulation of fluid flow in the unsaturated zone of Yucca Mountain, Nevada

    E-Print Network [OSTI]

    Zhang, Keni; Wu, Yu-Shu; Bodvarsson, G.S.

    2001-01-01

    Central Block Area, Yucca Mountain, Nye County, Nevada. Mapunsaturated zone, Yucca Mountain, Nevada. Water-Resourcesisotope distributions at Yucca Mountain. Sandia National

  10. Massively Parallel Spectral Element Large Eddy Simulation of a Turbulent Channel Using Wall Models 

    E-Print Network [OSTI]

    Rabau, Joshua I

    2013-05-01

    , Nek5000, and verify the method using a turbulent channel simulation. The first grid point is placed at y+ = 100, in the log-law region, for Re? = 950 and the sub-grid scales are modeled using a dynamic Smagorinski model. The results are then compared...

  11. An Example-Based Translation System on a Massively Parallel Machine Satoshi SATO

    E-Print Network [OSTI]

    Mitsunaga, Noriaki

    $K¡($9!#MBT3 $N¡B9T7O$O!"1) FbItK]Lu%G!¡%?%Y!¡%9!"2) :GE,¿H9g8!:w4o!"3) K]Lu%3%s %H%m!¡%i$N3 $D$N%b%8$r8!:wF~NO$H$7!":GE,¿H9g8!:w$r¡B9T$9$k!#$= $N7k2L$H$7$F!"%G!¡%?%Y!¡%9$+$i8!:wF~NO$KNI$/;w $? N(= 10% [Sato, 1993a] $r;2¿H$7$F$[$7$$!# 3 MBT3n: nCUBE2 ¿e$NMBT3 MBT3n $G$O!":GE,¿H9g8!:w$r¡B9T$9$kItJ,(A0@a%9

  12. Diffuse large B-cell lymphoma: sub-classification by massive parallel quantitative RT-PCR

    E-Print Network [OSTI]

    Xue, Xuemin; Zeng, Naiyan; Gao, Zifen; Du, Ming-Qing

    2014-11-24

    ;103:275-282. 7. Choi WW, Weisenburger DD, Greiner TC et al. A new immunostain algorithm classifies diffuse large B-cell lymphoma into molecular subtypes with high accuracy. Clin Cancer Res 2009;15:5494-5502. 8. Gutierrez-Garcia G, Cardesa-Salzmann T, Climent...

  13. Domain-specific translator and optimizer for massive on- chip parallelism

    E-Print Network [OSTI]

    Unat, Didem

    2012-01-01

    Linear Systems: a) Jacobi Method b) Gauss- Seidel Method c)Linear Systems: a) Jacobi Method b) Gauss-Seidel Method c)twice as fast as the Jacobi method. As shown in Fig 2.7-c,

  14. Enhanced killing of antibiotic-resistant bacteria enabled by massively parallel combinatorial genetics

    E-Print Network [OSTI]

    Ding, Huiming

    New therapeutic strategies are needed to treat infections caused by drug-resistant bacteria, which constitute a major growing threat to human health. Here, we use a high-throughput technology to identify combinatorial ...

  15. Scalable Compression and Replay of Communication Traces in Massively Parallel Environments

    E-Print Network [OSTI]

    Mueller, Frank

    , North Carolina State University, Raleigh, NC 2 Lawrence Livermore National Laboratory, CASC, Livermore is the mpiP tool that uses the profiling layer of MPI to gather user-configurable aggregate metrics-0237570. Part of this work was performed under the auspices of the U.S. Department of Energy by University

  16. Scalable Compression and Replay of Communication Traces in Massively Parallel Environments

    E-Print Network [OSTI]

    Mueller, Frank

    Noeth1 , Frank Mueller1 , Martin Schulz2 , Bronis R. de Supinski2 1 North Carolina State University 2 under the auspices of the U.S. Department of Energy by University of Cal- ifornia Lawrence Livermore that uses the profiling layer of MPI to gather user-configurable aggregate metrics for statistical analysis

  17. Switching Dynamics of Thin Film Ferroelectric Devices- A Massively Parallel Phase Field Study

    E-Print Network [OSTI]

    Ashraf, Khalid

    2013-01-01

    here are run on the NERSC super-computer Hopper. PETSC ishere are run on the NERSC super-computer Hopper. PETSC is

  18. Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer

    E-Print Network [OSTI]

    2008-01-01

    CONDUCTIVITY IMAGING OF HYDROCARBONS USING THE BLUE GENE/Lidentification of hydrocarbon filled layers in deepwater,”Remote sensing of hydrocarbon layers by seabed logging (

  19. CASL-U-2015-0170-000 SHIFT: A Massively Parallel Monte Carlo

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAudits &Bradbury Science Museum6 Shares1-000 SMR Fuel2-0007-000 COBRA-TF

  20. BlueGene/L Applications: Parallelism on a Massive Scale (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing Bacteria (Technical Report) | SciTechReport)(Technical Report)cellsEnergyepitaxySciTech

  1. BlueGene/L Applications: Parallelism on a Massive Scale (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing Bacteria (Technical Report) | SciTechReport)(Technical

  2. Writing parallel programs that work

    E-Print Network [OSTI]

    CERN. Geneva

    2012-01-01

    Serial algorithms typically run inefficiently on parallel machines. This may sound like an obvious statement, but it is the root cause of why parallel programming is considered to be difficult. The current state of the computer industry is still that almost all programs in existence are serial. This talk will describe the techniques used in the Intel Parallel Studio to provide a developer with the tools necessary to understand the behaviors and limitations of the existing serial programs. Once the limitations are known the developer can refactor the algorithms and reanalyze the resulting programs with the tools in the Intel Parallel Studio to create parallel programs that work. About the speaker Paul Petersen is a Sr. Principal Engineer in the Software and Solutions Group (SSG) at Intel. He received a Ph.D. degree in Computer Science from the University of Illinois in 1993. After UIUC, he was employed at Kuck and Associates, Inc. (KAI) working on auto-parallelizing compiler (KAP), and was involved in th...

  3. Massive Particles from Massless Spinors

    E-Print Network [OSTI]

    Marcu S. Cohen

    2008-09-26

    Spinors are lightlike. How do they combine to make massive particles? We visit the zoo of Lagrangian singularities, or caustics, in spacetime projections from spin space- the phase space of lightlike, 8- spinor flows. We find that the species living there are the elementary particles. Codimension J=(1,2,3,4) phase singularities - vortex lines, sheets, tubes, and knots, are classified by the Coxeter groups generated by multiplicity s reflections: "mass scatterings" off the vacuum spinors, that keep chiral pairs of matter envelopes confined to a timelike world tube, endowing a bispinor particle with mass. Using the volume in spin space as the action, the particle masses emerge in terms of the multiplicities, s: the number of null zigzags needed to close a cycle of mass scatterings. These mass values (calculated to lowest order in the vacuum intensity) are within a few percent of the observed masses for the leptons (J=1) and hadrons (J=3) ; but are up to 25 percent off for the mesons (J=2).

  4. Dynamic Star Formation in the Massive DR21 Filament

    SciTech Connect (OSTI)

    Schneider, N.; Csengeri, T.; Bontemps, S.; Motte, F.; Simon, R.; Hennebelle, P.; Federrath, C.; Klessen, R.; /ZAH, Heidelberg /KIPAC, Menlo Park

    2010-08-25

    The formation of massive stars is a highly complex process in which it is unclear whether the star-forming gas is in global gravitational collapse or an equilibrium state supported by turbulence and/or magnetic fields. By studying one of the most massive and dense star-forming regions in the Galaxy at a distance of less than 3 kpc, i.e. the filament containing the well-known sources DR21 and DR21(OH), we attempt to obtain observational evidence to help us to discriminate between these two views. We use molecular line data from our {sup 13}CO 1 {yields} 0, CS 2 {yields} 1, and N{sub 2}H{sup +} 1 {yields} 0 survey of the Cygnus X region obtained with the FCRAO and CO, CS, HCO{sup +}, N{sub 2}H{sup +}, and H{sub 2}CO data obtained with the IRAM 30m telescope. We observe a complex velocity field and velocity dispersion in the DR21 filament in which regions of the highest column-density, i.e., dense cores, have a lower velocity dispersion than the surrounding gas and velocity gradients that are not (only) due to rotation. Infall signatures in optically thick line profiles of HCO{sup +} and {sup 12}CO are observed along and across the whole DR21 filament. By modelling the observed spectra, we obtain a typical infall speed of {approx}0.6 km s{sup -1} and mass accretion rates of the order of a few 10{sup -3} M{sub {circle_dot}} yr{sup -1} for the two main clumps constituting the filament. These massive clumps (4900 and 3300 M{sub {circle_dot}} at densities of around 10{sup 5} cm{sup -3} within 1 pc diameter) are both gravitationally contracting. The more massive of the clumps, DR21(OH), is connected to a sub-filament, apparently 'falling' onto the clump. This filament runs parallel to the magnetic field. Conclusions. All observed kinematic features in the DR21 filament (velocity field, velocity dispersion, and infall), its filamentary morphology, and the existence of (a) sub-filament(s) can be explained if the DR21 filament was formed by the convergence of flows on large scales and is now in a state of global gravitational collapse. Whether this convergence of flows originated from self-gravity on larger scales or from other processes cannot be determined by the present study. The observed velocity field and velocity dispersion are consistent with results from (magneto)-hydrodynamic simulations where the cores lie at the stagnation points of convergent turbulent flows.

  5. Endpoint-based parallel data processing in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael E; Ratterman, Joseph D; Smith, Brian E

    2014-02-11

    Endpoint-based parallel data processing in a parallel active messaging interface ('PAMI') of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, the compute nodes coupled for data communications through the PAMI, including establishing a data communications geometry, the geometry specifying, for tasks representing processes of execution of the parallel application, a set of endpoints that are used in collective operations of the PAMI including a plurality of endpoints for one of the tasks; receiving in endpoints of the geometry an instruction for a collective operation; and executing the instruction for a collective opeartion through the endpoints in dependence upon the geometry, including dividing data communications operations among the plurality of endpoints for one of the tasks.

  6. Endpoint-based parallel data processing in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

    2014-08-12

    Endpoint-based parallel data processing in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, the compute nodes coupled for data communications through the PAMI, including establishing a data communications geometry, the geometry specifying, for tasks representing processes of execution of the parallel application, a set of endpoints that are used in collective operations of the PAMI including a plurality of endpoints for one of the tasks; receiving in endpoints of the geometry an instruction for a collective operation; and executing the instruction for a collective operation through the endpoints in dependence upon the geometry, including dividing data communications operations among the plurality of endpoints for one of the tasks.

  7. A new quasidilaton theory of massive gravity (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    A new quasidilaton theory of massive gravity Citation Details In-Document Search Title: A new quasidilaton theory of massive gravity We present a new quasidilaton theory of...

  8. SDSS-III: Massive Spectroscopic Surveys of the Distant Universe...

    Office of Scientific and Technical Information (OSTI)

    Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems Citation Details In-Document Search Title: SDSS-III: Massive...

  9. Binary Capture Rates for Massive Protostars

    E-Print Network [OSTI]

    Nickolas Moeckel; John Bally

    2007-04-09

    The high multiplicity of massive stars in dense, young clusters is established early in their evolution. The mechanism behind this remains unresolved. Recent results suggest that massive protostars may capture companions through disk interactions with much higher efficiency than their solar mass counterparts. However, this conclusion is based on analytic determinations of capture rates and estimates of the robustness of the resulting binaries. We present the results of coupled n-body and SPH simulations of star-disk encounters to further test the idea that disk-captured binaries contribute to the observed multiplicity of massive stars.

  10. Parallel partitioning strategies for the adaptive solution of conservation laws

    SciTech Connect (OSTI)

    Devine, K.D.; Flaherty, J.E.; Loy, R.M. [Rensselaer Polytechnic Institute, Troy, NY (United States)] [and others

    1995-12-31

    We describe and examine the performance of adaptive methods for Solving hyperbolic systems of conservation laws on massively parallel computers. The differential system is approximated by a discontinuous Galerkin finite element method with a hierarchical Legendre piecewise polynomial basis for the spatial discretization. Fluxes at element boundaries are computed by solving an approximate Riemann problem; a projection limiter is applied to keep the average solution monotone; time discretization is performed by Runge-Kutta integration; and a p-refinement-based error estimate is used as an enrichment indicator. Adaptive order (p-) and mesh (h-) refinement algorithms are presented and demonstrated. Using an element-based dynamic load balancing algorithm called tiling and adaptive p-refinement, parallel efficiencies of over 60% are achieved on a 1024-processor nCUBE/2 hypercube. We also demonstrate a fast, tree-based parallel partitioning strategy for three-dimensional octree-structured meshes. This method produces partition quality comparable to recursive spectral bisection at a greatly reduced cost.

  11. Massive galaxies at 1 < z < 3 

    E-Print Network [OSTI]

    Bruce, Victoria Ashley

    2014-06-28

    This thesis explores the evolution of massive galaxies (M * > 1011M ?) by conducting the largest multiple-component Sersic light-profile fitting study to date of the rest-frame optical and ultra-violet morphologies of ...

  12. Vacuum Instability in Topologically Massive Gauge Theory

    E-Print Network [OSTI]

    Alex Lewis

    1998-08-12

    We find the critical charge for a topologically massive gauge theory for any gauge group, generalising our earlier result for SU(2). The relation between critical charges in TMGT, singular vectors in the WZNW model and logarithmic CFT is investigated.

  13. Preprint of a paper to appear in Applied Optics, Vol. 33, No. 11, November 1994 A Scalable Optical Hypercubebased Interconnection Network for Massively

    E-Print Network [OSTI]

    Louri, Ahmed

    Preprint of a paper to appear in Applied Optics, Vol. 33, No. 11, November 1994 A Scalable Optical of massively parallel computers. This paper presents a new modular optical interconnection network, called an Optical Multi­Mesh Hypercube (OMMH), which is both size­ and time­scalable. The OMMH combines positive

  14. Top 10 Problems on Massive Stars

    E-Print Network [OSTI]

    Cassio Barbosa; Donald Figer

    2005-10-18

    We have asked a number of researchers to compile their lists of the top 10 problems in the field of massive stars. This paper is a compilation of these lists. We attempted to survey observers and theorists and those studying all evolutionary stages in the lives of massive stars. Each list reflects the proposer's personal point of view, but hopefully, this compilation will motivate new young astronomers and begin a new series of discussion.

  15. Massivizing Online Games: Distributed Computing Challenges and

    E-Print Network [OSTI]

    Langendoen, Koen

    .st.ewi.tudelft.nl #12;(TU) Delft ­ the Netherlands ­ Europe founded 13th century pop: 100,000 pop.: 100,000 pop: 16.5 M founded 1842 pop: 13,000 pop.: 100,000 (We are here) #12;Why Social Gaming? Massivizing Social Games Gaming used to be art, may now be computingOnline Gaming used to be art, may now be computing Massivizing

  16. Lemon: an MPI parallel I/O library for data encapsulation using LIME

    E-Print Network [OSTI]

    Albert Deuzeman; Siebren Reker; Carsten Urbach; for the ETM Collaboration

    2011-06-21

    We introduce Lemon, an MPI parallel I/O library that is intended to allow for efficient parallel I/O of both binary and metadata on massively parallel architectures. Motivated by the demands of the Lattice Quantum Chromodynamics community, the data is stored in the SciDAC Lattice QCD Interchange Message Encapsulation format. This format allows for storing large blocks of binary data and corresponding metadata in the same file. Even if designed for LQCD needs, this format might be useful for any application with this type of data profile. The design, implementation and application of Lemon are described. We conclude with presenting the excellent scaling properties of Lemon on state of the art high performance computers.

  17. Parallel continuation-based global optimization for molecular conformation and protein folding

    SciTech Connect (OSTI)

    Coleman, T.F.; Wu, Z. [Cornell Univ., Ithaca, NY (United States)

    1994-12-31

    This paper presents the authors` recent work on developing parallel algorithms and software for solving the global minimization problem for molecular conformation, especially protein folding. Global minimization problems are difficult to solve when the objective functions have many local minimizers, such as the energy functions for protein folding. In their approach, to avoid directly minimizing a ``difficult`` function, a special integral transformation is introduced to transform the function into a class of gradually deformed, but ``smoother`` or ``easier`` functions. An optimization procedure is then applied to the new functions successively, to trace their solutions back to the original function. The method can be applied to a large class of nonlinear partially separable functions including energy functions for molecular conformation and protein folding. Mathematical theory for the method, as a special continuation approach to global optimization, is established. Algorithms with different solution tracing strategies are developed. Different levels of parallelism are exploited for the implementation of the algorithms on massively parallel architectures.

  18. Tutorial: Parallel Simulation on Supercomputers

    SciTech Connect (OSTI)

    Perumalla, Kalyan S [ORNL

    2012-01-01

    This tutorial introduces typical hardware and software characteristics of extant and emerging supercomputing platforms, and presents issues and solutions in executing large-scale parallel discrete event simulation scenarios on such high performance computing systems. Covered topics include synchronization, model organization, example applications, and observed performance from illustrative large-scale runs.

  19. Designing a parallel simula machine

    SciTech Connect (OSTI)

    Papazoglou, M.P.; Georgiadis, P.I.; Maritsas, D.G.

    1983-10-01

    The parallel simula machine (PSM) architecture is based upon a master/slave topology, incorporating a master microprocessor. Interconnection circuitry between the master and slave processor modules uses a timesharing system bus and various programmable interrupt control units. Common and private memory modules reside in the PSM, and direct memory access transfers ease the master processor's workload. 5 references.

  20. Parallel HSL port Control Network

    E-Print Network [OSTI]

    Glück, Olivier

    Parallel HSL port FastHSL board HSL links Ethernet Control Network Node 1 PC mother board PCI Bus PCI-DDC Rcube PC mother board Node 3 PCI-DDC Rcube Node 2 PC mother board PCI-DDC Rcube THE MPC is the HSL network router, and PCI-DDC the network controller implementing the Direct Deposit State Less

  1. Architecture, implementation and parallelization of the software to search for periodic gravitational wave signals

    E-Print Network [OSTI]

    Gevorg Poghosyan; Sanchit Matta; Achim Streit; Micha? Bejger; Andrzej Królak

    2014-10-14

    The parallelization, design and scalability of the \\sky code to search for periodic gravitational waves from rotating neutron stars is discussed. The code is based on an efficient implementation of the F-statistic using the Fast Fourier Transform algorithm. To perform an analysis of data from the advanced LIGO and Virgo gravitational wave detectors' network, which will start operating in 2015, hundreds of millions of CPU hours will be required - the code utilizing the potential of massively parallel supercomputers is therefore mandatory. We have parallelized the code using the Message Passing Interface standard, implemented a mechanism for combining the searches at different sky-positions and frequency bands into one extremely scalable program. The parallel I/O interface is used to escape bottlenecks, when writing the generated data into file system. This allowed to develop a highly scalable computation code, which would enable the data analysis at large scales on acceptable time scales. Benchmarking of the code on a Cray XE6 system was performed to show efficiency of our parallelization concept and to demonstrate scaling up to 50 thousand cores in parallel.

  2. Effects of floating-point non-associativity on numerical computations on massively multithreaded systems

    SciTech Connect (OSTI)

    Villa, Oreste; Chavarría-Miranda, Daniel; Gurumoorthi, Vidhya; Marquez, Andres; Krishnamoorthy, Sriram

    2009-05-03

    Floating-point addition and multiplication are not necessarily associative. When performing those operations over large numbers of operands with different magnitudes, the order in which individual operations are performed can affect the final result. On massively multithreaded systems, when performing parallel reductions, the non-deterministic nature of numerical operation interleaving can lead to non-deterministic numerical results. We have investigated the effect of this problem on the convergence of a conjugate gradient calculation used as part of a power grid analysis application.

  3. Dark/visible parallel universes and Big Bang nucleosynthesis

    SciTech Connect (OSTI)

    Bertulani, C. A.; Frederico, T.; Fuqua, J.; Hussein, M. S.; Oliveira, O.; Paula, W. de [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil); Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP, Brazil and Departamento de Fisica, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil)

    2012-11-20

    We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds, the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB) bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.

  4. Parallelization and checkpointing of GPU applications through program transformation

    SciTech Connect (OSTI)

    Solano-Quinde, Lizandro Dami#19; an [Ames Laboratory

    2012-11-15

    GPUs have emerged as a powerful tool for accelerating general-purpose applications. The availability of programming languages that makes writing general-purpose applications for running on GPUs tractable have consolidated GPUs as an alternative for accelerating general purpose applications. Among the areas that have beneffited from GPU acceleration are: signal and image processing, computational fluid dynamics, quantum chemistry, and, in general, the High Performance Computing (HPC) Industry. In order to continue to exploit higher levels of parallelism with GPUs, multi-GPU systems are gaining popularity. In this context, single-GPU applications are parallelized for running in multi-GPU systems. Furthermore, multi-GPU systems help to solve the GPU memory limitation for applications with large application memory footprint. Parallelizing single-GPU applications has been approached by libraries that distribute the workload at runtime, however, they impose execution overhead and are not portable. On the other hand, on traditional CPU systems, parallelization has been approached through application transformation at pre-compile time, which enhances the application to distribute the workload at application level and does not have the issues of library-based approaches. Hence, a parallelization scheme for GPU systems based on application transformation is needed. Like any computing engine of today, reliability is also a concern in GPUs. GPUs are vulnerable to transient and permanent failures. Current checkpoint/restart techniques are not suitable for systems with GPUs. Checkpointing for GPU systems present new and interesting challenges, primarily due to the natural differences imposed by the hardware design, the memory subsystem architecture, the massive number of threads, and the limited amount of synchronization among threads. Therefore, a checkpoint/restart technique suitable for GPU systems is needed. The goal of this work is to exploit higher levels of parallelism and to develop support for application-level fault tolerance in applications using multiple GPUs. Our techniques reduce the burden of enhancing single-GPU applications to support these features. To achieve our goal, this work designs and implements a framework for enhancing a single-GPU OpenCL application through application transformation.

  5. Parallel Algorithms for Medical Informatics on Data-Parallel Many-Core Processors

    E-Print Network [OSTI]

    Moazeni, Maryam

    2013-01-01

    and analysis of parallel algorithms." , Prentice Hall, Newsymposium on Discrete algorithms, pp. 271-280. Society forintroduction to parallel algorithms. Addison Wesley Longman

  6. SED modeling of Young Massive Stars

    E-Print Network [OSTI]

    Thomas P. Robitaille

    2007-11-27

    In this contribution, I review the applications and potential limitations of the spectral energy distribution fitting tool that I have developed, with a strong emphasis on the limits to which this tool can be used to improve our understanding of massive star formation. I discuss why our current grid of models cannot be used to distinguish between the several competing theories of massive star formation. I also discuss stellar mass determinations, artificial correlations between parameters in the grid of models, multiplicity, confusion, dust assumptions, and unique fits. I briefly review the improvements we intend to carry out for our next grid of models, which will eliminate many of these limitations. Finally, I show examples of applications of this tool to massive young stars.

  7. Parallel supercomputing: Advanced methods, algorithms and software for large-scale problems. Progress report, April 1991--April 1992

    SciTech Connect (OSTI)

    Carey, G.F.; Young, D.M.

    1992-04-01

    Research has continued with excellent progress and new results on methodology and algorithms. We have also made supporting benchmark application studies on representative parallel computing architectures. Results from these research studies have been reported at scientific meetings, as technical reports and as journal publications. A list of pertinent presentations and publications is attached. The work on parallel element-by-element techniques and domain decomposition schemes has developed well. In particular, we have focused on the use of finite element spectral methods (or high p methods) on distributed massively parallel systems. The approach has been implemented in a prototype finite element program for solution of coupled Navier Stokes flow and transport processes. This class of problems is of fundamental interest and basic to many ``grand challenge`` type problems for which parallel supercomputing is warranted.

  8. Growth histories in bimetric massive gravity

    SciTech Connect (OSTI)

    Berg, Marcus; Buchberger, Igor; Enander, Jonas; Mörtsell, Edvard; Sjörs, Stefan E-mail: igor.buchberger@kau.se E-mail: edvard@fysik.su.se

    2012-12-01

    We perform cosmological perturbation theory in Hassan-Rosen bimetric gravity for general homogeneous and isotropic backgrounds. In the de Sitter approximation, we obtain decoupled sets of massless and massive scalar gravitational fluctuations. Matter perturbations then evolve like in Einstein gravity. We perturb the future de Sitter regime by the ratio of matter to dark energy, producing quasi-de Sitter space. In this more general setting the massive and massless fluctuations mix. We argue that in the quasi-de Sitter regime, the growth of structure in bimetric gravity differs from that of Einstein gravity.

  9. Massive Feynman integrals and electroweak corrections

    E-Print Network [OSTI]

    Janusz Gluza; Tord Riemann

    2015-01-19

    There are steady advances in the calculation of electroweak corrections to massive scattering problems at colliders, from the very beginning in the nineteen seventies until contemporary developments. Recent years brought a remarkable progress due to new calculational technologies. This was motivated by demands from phenomenological applications at particle accelerators: higher multiplicities of the final states, extreme kinematics, need of higher precision and thus of higher orders in perturbation theory. We describe selected contributions from the project "Massive particle production" of Sonderforschungsbereich/Transregio 9 of Deutsche Forschungsgemeinschaft.

  10. Primordial Li abundance and massive particles

    SciTech Connect (OSTI)

    Latin-Capital-Letter-Eth apo, H.

    2012-10-20

    The problem of the observed lithium abundance coming from the Big Bang Nucleosynthesis is as of yet unsolved. One of the proposed solutions is including relic massive particles into the Big Bang Nucleosynthesis. We investigated the effects of such particles on {sup 4}HeX{sup -}+{sup 2}H{yields}{sup 6}Li+X{sup -}, where the X{sup -} is the negatively charged massive particle. We demonstrate the dominance of long-range part of the potential on the cross-section.

  11. The SpiceC Parallel Programming System

    E-Print Network [OSTI]

    Feng, Min

    2012-01-01

    6.5 Programming Speculative Parallel Loops on GPUs 6.5.17.3 SpiceC Programming on Clusters . . . . . . . 7.48 Related Work 8.1 Parallel Programming . . . . . . . . . .

  12. Parallelism Constraints Katrin Erk Joachim Niehren

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Parallelism Constraints Katrin Erk Joachim Niehren Programming Systems Lab, Universit¨at des Saarlandes, Saarbr¨ucken, Germany www.ps.uni-sb.de/~{erk,niehren} Abstract. Parallelism constraints

  13. On-the-fly pipeline parallelism

    E-Print Network [OSTI]

    Lee, I-Ting Angelina

    Pipeline parallelism organizes a parallel program as a linear sequence of s stages. Each stage processes elements of a data stream, passing each processed data element to the next stage, and then taking on a new element ...

  14. Parallelization

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| Department ofStephen PSeptember|March Study

  15. Player Dynamics in Massively Multiplayer Online Games

    E-Print Network [OSTI]

    of player session lengths, downtimes, inter-arrival times, and availability, the aggregate player churn rate;Keywords: games, massively multiplayer, measurement, player dynamics, churn #12;Abstract Millions of people into account the churn inherent in MMOG player participation. This paper presents the results of an extensive

  16. Player Dynamics in Massively Multiplayer Online Games

    E-Print Network [OSTI]

    of player session lengths, downtimes, inter­arrival times, and availability, the aggregate player churn rate #12; Keywords: games, massively multiplayer, measurement, player dynamics, churn #12; Abstract into account the churn inherent in MMOG player participation. This paper presents the results of an extensive

  17. ADAPTIVE DENSITY ESTIMATION WITH MASSIVE DATA SETS

    E-Print Network [OSTI]

    Scott, David W.

    recognition, density estima­ tion, and data visualization. However, one already hears stories of logistic the data, and some require the data to be in core. 1.1 Reversing Efficiency Roles What general solution can we propose? It is our po­ sition that massive data sets reverse our usual focus This research

  18. A Novel Application of Parallel Betweenness Centrality to Power Grid Contingency Analysis

    SciTech Connect (OSTI)

    Jin, Shuangshuang; Huang, Zhenyu; Chen, Yousu; Chavarría-Miranda, Daniel; Feo, John T.; Wong, Pak C.

    2010-04-19

    In Energy Management Systems, contingency analysis is commonly performed for identifying and mitigating potentially harmful power grid component failures. The exponentially increasing combinatorial number of failure modes imposes a significant computational burden for massive contingency analysis. It is critical to select a limited set of high-impact contingency cases within the constraint of computing power and time requirements to make it possible for real-time power system vulnerability assessment. In this paper, we present a novel application of parallel betweenness centrality to power grid contingency selection. We cross-validate the proposed method using the model and data of the western US power grid, and implement it on a Cray XMT system - a massively multithreaded architecture - leveraging its advantages for parallel execution of irregular algorithms, such as graph analysis. We achieve a speedup of 55 times (on 64 processors) compared against the single-processor version of the same code running on the Cray XMT. We also compare an OpenMP-based version of the same code running on an HP Superdome shared-memory machine. The performance of the Cray XMT code shows better scalability and resource utilization, and shorter execution time for large-scale power grids. This proposed approach has been evaluated in PNNL’s Electricity Infrastructure Operations Center (EIOC). It is expected to provide a quick and efficient solution to massive contingency selection problems to help power grid operators to identify and mitigate potential widespread cascading power grid failures in real time.

  19. Self-similar Fragmentation Regulated by Magnetic Fields in a Massive Star Forming Filament

    E-Print Network [OSTI]

    Li, Hua-bai; Otto, Frank; Leung, Po Kin; Sridharan, T K; Zhang, Qizhou; Liu, Hauyu; Tang, Ya-Wen; Qiu, Keping

    2015-01-01

    Most molecular clouds are filamentary or elongated. Among those forming low-mass stars, their long axes tend to be either parallel or perpendicular to the large-scale (10-100 pc) magnetic field (B-field) in the surrounding inter cloud medium. This arises because, along the dynamically dominant B-fields, the competition between self-gravity and turbulent pressure will shape the cloud to be elongated either perpendicular or parallel to the fields. Recent study also suggested that, on the scales of 0.1-0.01 pc, fields are dynamically important within cloud cores forming massive stars. But whether the core field morphologies are inherited from the inter cloud medium or governed by cloud turbulence is under vigorous debate, so is the role played by B-fields in cloud fragmentation at 10 - 0.1 pc scales. Here we report B-field maps covering 100-0.01 pc scales inferred from polarimetric observations of a massive-star forming region, NGC 6334. First, the main filament also lies perpendicular to the ambient field. NGC ...

  20. Alexandru Iosup Parallel and Distributed Systems Group

    E-Print Network [OSTI]

    Langendoen, Koen

    Online Games: High Performance Computing and High Quality Time 1 Massivizing Social Games: High,000,000 active players Massivizing Social Games: High Performance Computing and High Quality Time ­ A. Iosup 3 Games: High Performance Computing and High Quality Time ­ A. Iosup 4 Sources: MMOGChart, own research

  1. Search for massive resonances in dijet systems containing jets...

    Office of Scientific and Technical Information (OSTI)

    massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at ?s 8 TeV Re-direct Destination: Search for massive resonances in dijet...

  2. 3D Simulations of Thermonuclear Supernovae From Very Massive Stars

    E-Print Network [OSTI]

    Crowther, Paul

    3D Simulations of Thermonuclear Supernovae From Very Massive Stars Ke-Jung (Ken) Chen Johnston #12;3D Simulations of Thermonuclear Supernovae From Very Massive Stars Ke-Jung (Ken) Chen Johnston

  3. Time parallel gravitational collapse simulation

    E-Print Network [OSTI]

    Kreienbuehl, Andreas; Ruprecht, Daniel; Krause, Rolf

    2015-01-01

    This article demonstrates the applicability of the parallel-in-time method Parareal to the numerical solution of the Einstein gravity equations for the spherical collapse of a massless scalar field. To account for the shrinking of the spatial domain in time, a tailored load balancing scheme is proposed and compared to load balancing based on number of time steps alone. The performance of Parareal is studied for both the sub-critical and black hole case; our experiments show that Parareal generates substantial speedup and, in the super-critical regime, can also reproduce the black hole mass scaling law.

  4. Parallel Computing Summer Research Internship

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesseworkSURVEYI/O Streams forOrhanTheoreticalSecurity Complex3Parallel

  5. Parallel_HDF5.pptx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesseworkSURVEYI/O Streams forOrhanTheoreticalSecurityParallel I/OA Brief

  6. Xyce parallel electronic simulator design.

    SciTech Connect (OSTI)

    Thornquist, Heidi K.; Rankin, Eric Lamont; Mei, Ting; Schiek, Richard Louis; Keiter, Eric Richard; Russo, Thomas V.

    2010-09-01

    This document is the Xyce Circuit Simulator developer guide. Xyce has been designed from the 'ground up' to be a SPICE-compatible, distributed memory parallel circuit simulator. While it is in many respects a research code, Xyce is intended to be a production simulator. As such, having software quality engineering (SQE) procedures in place to insure a high level of code quality and robustness are essential. Version control, issue tracking customer support, C++ style guildlines and the Xyce release process are all described. The Xyce Parallel Electronic Simulator has been under development at Sandia since 1999. Historically, Xyce has mostly been funded by ASC, the original focus of Xyce development has primarily been related to circuits for nuclear weapons. However, this has not been the only focus and it is expected that the project will diversify. Like many ASC projects, Xyce is a group development effort, which involves a number of researchers, engineers, scientists, mathmaticians and computer scientists. In addition to diversity of background, it is to be expected on long term projects for there to be a certain amount of staff turnover, as people move on to different projects. As a result, it is very important that the project maintain high software quality standards. The point of this document is to formally document a number of the software quality practices followed by the Xyce team in one place. Also, it is hoped that this document will be a good source of information for new developers.

  7. Dark energy as a massive vector field

    E-Print Network [OSTI]

    C. G. Boehmer; T. Harko

    2007-01-11

    We propose that the Universe is filled with a massive vector field, non-minimally coupled to gravitation. The field equations of the model are consistently derived and their application to cosmology is considered. The Friedmann equations acquire an extra dark-energy component, which is proportional to the mass of the vector particle. This leads to a late-time accelerated de Sitter type expansion. The free parameters of the model (gravitational coupling constants and initial value of the cosmological vector field) can be estimated by using the PPN solar system constraints. The mass of the cosmological massive vector particle, which may represent the main component of the Universe, is of the order of 10^-63 g.

  8. Consistent massive graviton on arbitrary backgrounds

    E-Print Network [OSTI]

    Laura Bernard; Cedric Deffayet; Mikael von Strauss

    2015-05-15

    We obtain the fully covariant linearized field equations for the metric perturbation in the de Rham-Gabadadze-Tolley (dRGT) ghost free massive gravities. For a subset of these theories, we show that the non dynamical metric that appears in the dRGT setup can be completely eliminated leading to the theory of a massive graviton moving in a single metric. This has a mass term which contains non trivial contributions of the space-time curvature. We show further how 5 covariant constraints can be obtained including one which leads to the tracelessness of the graviton on flat space-time and removes the Boulware-Deser ghost. The 5 constraints are obtained for a background metric which is arbitrary, i.e. which does not have to obey the background field equations.

  9. Massive Protoplanetary Disks in the Trapezium Region

    E-Print Network [OSTI]

    J. A. Eisner; John M. Carpenter

    2006-01-02

    (abridged) We determine the disk mass distribution around 336 stars in the young Orion Nebula cluster by imaging a 2.5' x 2.5' region in 3 mm continuum emission with the Owens Valley Millimeter Array. For this sample of 336 stars, we observe 3 mm emission above the 3-sigma noise level toward ten sources, six of which have also been detected optically in silhouette against the bright nebular background. In addition, we detect 20 objects that do not correspond to known near-IR cluster members. Comparisons of our measured fluxes with longer wavelength observations enable rough separation of dust emission from thermal free-free emission, and we find substantial dust emission toward most objects. For the ten objects detected at both 3 mm and near-IR wavelengths, eight exhibit substantial dust emission. Excluding the high-mass stars and assuming a gas-to-dust ratio of 100, we estimate circumstellar masses ranging from 0.13 to 0.39 Msun. For the cluster members not detected at 3 mm, images of individual objects are stacked to constrain the mean 3 mm flux of the ensemble. The average flux is detected at the 3-sigma confidence level, and implies an average disk mass of 0.005 Msun, comparable to the minimum mass solar nebula. The percentage of stars in Orion surrounded by disks more massive than ~0.1 Msun is consistent with the disk mass distribution in Taurus, and we argue that massive disks in Orion do not appear to be truncated through close encounters with high-mass stars. Comparison of the average disk mass and number of massive dusty structures in Orion with similar surveys of the NGC 2024 and IC 348 clusters constrains the evolutionary timescales of massive circumstellar disks in clustered environments.

  10. Sudden singularities survive massive quantum particle production

    E-Print Network [OSTI]

    J. D. Barrow; A. B. Batista; G. Dito; J. C. Fabris; M. J. S. Houndjo

    2012-06-28

    We solve the Klein-Gordon equation for a massive, non-minimally coupled scalar field, with a conformal coupling, undergoing cosmological evolution from a radiation-dominated phase to a future sudden singularity. We show that, after regularisation, the energy of the created particles is zero and the back-reaction from quantum effects does not change the evolution of the universe near the future singularity and cannot prevent the finite-time sudden singularity.

  11. Antenna Splitting Functions for Massive Particles

    SciTech Connect (OSTI)

    Larkoski, Andrew J.; Peskin, Michael E.; /SLAC

    2011-06-22

    An antenna shower is a parton shower in which the basic move is a color-coherent 2 {yields} 3 parton splitting process. In this paper, we give compact forms for the spin-dependent antenna splitting functions involving massive partons of spin 0 and spin 1/2. We hope that this formalism we have presented will be useful in describing the QCD dynamics of the top quark and other heavy particles at LHC.

  12. Cosmology in general massive gravity theories

    SciTech Connect (OSTI)

    Comelli, D.; Nesti, F.; Pilo, L. E-mail: fabrizio.nesti@aquila.infn.it

    2014-05-01

    We study the cosmological FRW flat solutions generated in general massive gravity theories. Such a model are obtained adding to the Einstein General Relativity action a peculiar non derivative potentials, function of the metric components, that induce the propagation of five gravitational degrees of freedom. This large class of theories includes both the case with a residual Lorentz invariance as well as the case with rotational invariance only. It turns out that the Lorentz-breaking case is selected as the only possibility. Moreover it turns out that that perturbations around strict Minkowski or dS space are strongly coupled. The upshot is that even though dark energy can be simply accounted by massive gravity modifications, its equation of state w{sub eff} has to deviate from -1. Indeed, there is an explicit relation between the strong coupling scale of perturbations and the deviation of w{sub eff} from -1. Taking into account current limits on w{sub eff} and submillimiter tests of the Newton's law as a limit on the possible strong coupling scale, we find that it is still possible to have a weakly coupled theory in a quasi dS background. Future experimental improvements on short distance tests of the Newton's law may be used to tighten the deviation of w{sub eff} form -1 in a weakly coupled massive gravity theory.

  13. Device for balancing parallel strings

    DOE Patents [OSTI]

    Mashikian, Matthew S. (Storrs, CT)

    1985-01-01

    A battery plant is described which features magnetic circuit means in association with each of the battery strings in the battery plant for balancing the electrical current flow through the battery strings by equalizing the voltage across each of the battery strings. Each of the magnetic circuit means generally comprises means for sensing the electrical current flow through one of the battery strings, and a saturable reactor having a main winding connected electrically in series with the battery string, a bias winding connected to a source of alternating current and a control winding connected to a variable source of direct current controlled by the sensing means. Each of the battery strings is formed by a plurality of batteries connected electrically in series, and these battery strings are connected electrically in parallel across common bus conductors.

  14. Parallel auto-correlative statistics with VTK.

    SciTech Connect (OSTI)

    Pebay, Philippe Pierre; Bennett, Janine Camille

    2013-08-01

    This report summarizes existing statistical engines in VTK and presents both the serial and parallel auto-correlative statistics engines. It is a sequel to [PT08, BPRT09b, PT09, BPT09, PT10] which studied the parallel descriptive, correlative, multi-correlative, principal component analysis, contingency, k-means, and order statistics engines. The ease of use of the new parallel auto-correlative statistics engine is illustrated by the means of C++ code snippets and algorithm verification is provided. This report justifies the design of the statistics engines with parallel scalability in mind, and provides scalability and speed-up analysis results for the autocorrelative statistics engine.

  15. Parallel distributed programming with Haskell + PVM

    E-Print Network [OSTI]

    Winstanley, N.; O'Donnell, J.T.

    Winstanley,N. O'Donnell,J.T. Proceedings of Euro-Par'97: Parallel Processing. Volume No 1300 pp 670-677 Springer

  16. Cost hierarchies for abstract parallel machines

    E-Print Network [OSTI]

    O'Donnell, J.T.

    O'Donnell,J.T. Rauber,T. Ruenger,G. 13th International Workshop on Languages and Compilers for Parallel Computing (LCPC 2000) LNCS, Springer

  17. The Parallel Landscape Part I. Preliminaries

    E-Print Network [OSTI]

    Kaminsky, Alan

    prediction, phar maceutical drug design), geology (seismic data analysis, oil and mineral prospecting. The Parallel Landscape 1­3 · Computational finance: asset pricing, derivative pricing, market model ing

  18. Parallel computing in enterprise modeling.

    SciTech Connect (OSTI)

    Goldsby, Michael E.; Armstrong, Robert C.; Shneider, Max S.; Vanderveen, Keith; Ray, Jaideep; Heath, Zach; Allan, Benjamin A.

    2008-08-01

    This report presents the results of our efforts to apply high-performance computing to entity-based simulations with a multi-use plugin for parallel computing. We use the term 'Entity-based simulation' to describe a class of simulation which includes both discrete event simulation and agent based simulation. What simulations of this class share, and what differs from more traditional models, is that the result sought is emergent from a large number of contributing entities. Logistic, economic and social simulations are members of this class where things or people are organized or self-organize to produce a solution. Entity-based problems never have an a priori ergodic principle that will greatly simplify calculations. Because the results of entity-based simulations can only be realized at scale, scalable computing is de rigueur for large problems. Having said that, the absence of a spatial organizing principal makes the decomposition of the problem onto processors problematic. In addition, practitioners in this domain commonly use the Java programming language which presents its own problems in a high-performance setting. The plugin we have developed, called the Parallel Particle Data Model, overcomes both of these obstacles and is now being used by two Sandia frameworks: the Decision Analysis Center, and the Seldon social simulation facility. While the ability to engage U.S.-sized problems is now available to the Decision Analysis Center, this plugin is central to the success of Seldon. Because Seldon relies on computationally intensive cognitive sub-models, this work is necessary to achieve the scale necessary for realistic results. With the recent upheavals in the financial markets, and the inscrutability of terrorist activity, this simulation domain will likely need a capability with ever greater fidelity. High-performance computing will play an important part in enabling that greater fidelity.

  19. 3: Parallelism in Microprocessors Course on "Scalable Computing". Vittorio Scarano 3: Parallelism in Microprocessors

    E-Print Network [OSTI]

    Scarano, Vittorio

    -core Architectures From Multi-core to Many-core Power Management Some challenges ahead 2/65 3: Parallelism Multi-core to Many-core Power Management Some challenges ahead 3/65 3: Parallelism in Microprocessors-core to Many-core Power Management Some challenges ahead 5/65 3: Parallelism in Microprocessors Course

  20. Roles of Parallelizing CompilersRoles of Parallelizing Compilers for Low Power Manycoresy

    E-Print Network [OSTI]

    Kasahara, Hironori

    Roles of Parallelizing CompilersRoles of Parallelizing Compilers for Low Power Manycoresy Hironori improve effective performance, cost-performance and Needs of Parallelizing Compilers for Manycores p p p of consumed power byReduction of consumed power by compiler control DVFS and Power gating with hardware

  1. Parallel 3-D Electromagnetic Particle code using High Performance Fortran: Parallel TRISTAN

    E-Print Network [OSTI]

    Nishikawa, Ken-Ichi

    :{cai, ytli, cjxiao, yxy }@is.tsukuba.ac.jp 2 National Space Science and Technology Center, 320 Sparkman Drive using High Performance Fortran (HPF) as a RPM (Real Parallel Machine). In the parallelized HPF code to realize the standard High Performance Fortran specification and can be installed on a number of parallel

  2. Parallel Application Software on High Performance Survey of Parallel Software Packages of potential

    E-Print Network [OSTI]

    Ferreira-Resende, António

    i Parallel Application Software on High Performance Computers Survey of Parallel Software Packages.Lockey Edition 3: 24th June 1996 Abstract Parallel software packages which may be of use in scientific, software packages, scientific applications. This report is available from http://www.dl.ac.uk/TCSC/HPCI/ c

  3. New approach for the solution of optimal control problems on parallel machines. Doctoral thesis

    SciTech Connect (OSTI)

    Stech, D.J.

    1990-01-01

    This thesis develops a highly parallel solution method for nonlinear optimal control problems. Balakrishnan's epsilon method is used in conjunction with the Rayleigh-Ritz method to convert the dynamic optimization of the optimal control problem into a static optimization problem. Walsh functions and orthogonal polynomials are used as basis functions to implement the Rayleigh-Ritz method. The resulting static optimization problem is solved using matrix operations which have well defined massively parallel solution methods. To demonstrate the method, a variety of nonlinear optimal control problems are solved. The nonlinear Raleigh problem with quadratic cost and nonlinear van der Pol problem with quadratic cost and terminal constraints on the states are solved in both serial and parallel on an eight processor Intel Hypercube. The solutions using both Walsh functions and Legendre polynomials as basis functions are given. In addition to these problems which are solved in parallel, a more complex nonlinear minimum time optimal control problem and nonlinear optimal control problem with an inequality constraint on the control are solved. Results show the method converges quickly, even from relatively poor initial guesses for the nominal trajectories.

  4. PARALLEL EVOLUTIONARY ALGORITHMS FOR UAV PATH PLANNING

    E-Print Network [OSTI]

    PARALLEL EVOLUTIONARY ALGORITHMS FOR UAV PATH PLANNING Dong Jia Post-Doctoral Research Associate vehicles (UAVs). Premature convergence prevents evolutionary-based algorithms from reaching global optimal. To overcome this problem, this paper presents a framework of parallel evolutionary algorithms for UAV path

  5. A Parallel Geometric Multifrontal Solver Using

    E-Print Network [OSTI]

    We report the detailed parallel performance results in Table III. We also show .... Basic Energy Sciences/Biological and Environmental Research/High Energy Physics/Fusion Energy Sci- ences/Nuclear Physics). The research of ... In Parallel and Distributed Systems (ICPADS), 2010 IEEE 16th International Con- ference on.

  6. Addendum to "Superconnections and Parallel Transport"

    E-Print Network [OSTI]

    Dumitrescu, Florin

    2011-01-01

    In this addendum to our article "Superconnections and Parallel Transport" we give an alternate construction to the parallel transport of a superconnection contained in Corollary 4.4 of \\cite{D1}, which has the advantage that is independent on the various ways a superconnection splits as a connection plus a bundle endomorphism valued form.

  7. Embedding infinitely parallel computation in Newtonian kinematics

    E-Print Network [OSTI]

    Tucker, John V.

    Embedding infinitely parallel computation in Newtonian kinematics E.J. Beggs a,1 J.V. Tucker b,2 a, infinite parallellism 1 Email: e.j.beggs@swansea.ac.uk 2 Email: j.v.tucker@swansea.ac.uk Preprint submitted

  8. Communication Characteristics in the NAS Parallel Benchmarks

    E-Print Network [OSTI]

    Communication Characteristics in the NAS Parallel Benchmarks Ahmad Faraj Xin Yuan Department-- In this paper, we investigate the communication characteris- tics of the Message Passing Interface (MPI) implementation of the NAS parallel benchmarks and study the effectiveness of com- piled communication for MPI

  9. Applications Parallel PIC plasma simulation through particle

    E-Print Network [OSTI]

    Vlad, Gregorio

    Applications Parallel PIC plasma simulation through particle decomposition techniques B. Di Martino 2000 Abstract Parallelization of a particle-in-cell (PIC) code has been accomplished through of these interactions can then be obtained by particle-in-cell (PIC) simulation techniques [2], which consist in fol

  10. IBM Watson, Nov. 2008 1 Parallel Scheduling

    E-Print Network [OSTI]

    Guestrin, Carlos

    IBM Watson, Nov. 2008 1 Parallel Scheduling Theory and Practice Guy Blelloch Carnegie Mellon University #12;IBM Watson, Nov. 2008 2 Parallel Languages User Scheduled MPI, Pthreads (typical usage) System. #12;IBM Watson, Nov. 2008 3 Example: Quicksort procedure QUICKSORT(S): if S contains at most one

  11. IBM Parallel Environment for Linux Introduction

    E-Print Network [OSTI]

    Hickman, Mark

    IBM Parallel Environment for Linux Introduction Version 4 Release 2 SA23-2218-00 #12;#12;IBM 2006) This edition applies to version 4, release 2, modification 0 of IBM Parallel Environment by a vertical line ( | ) to the left of the change. IBM welcomes your comments. A form for readers' comments may

  12. A new quasidilaton theory of massive gravity

    SciTech Connect (OSTI)

    Mukohyama, Shinji

    2014-12-01

    We present a new quasidilaton theory of Poincare invariant massive gravity, based on the recently proposed framework of matter coupling that makes it possible for the kinetic energy of the quasidilaton scalar to couple to both physical and fiducial metrics simultaneously. We find a scaling-type exact solution that expresses a self-accelerating de Sitter universe, and then analyze linear perturbations around it. It is shown that in a range of parameters all physical degrees of freedom have non-vanishing quadratic kinetic terms and are stable in the subhorizon limit, while the effective Newton's constant for the background is kept positive.

  13. Transport coefficients of a massive pion gas

    E-Print Network [OSTI]

    D. Fernandez-Fraile; A. Gomez Nicola

    2009-12-20

    We review or main results concerning the transport coefficients of a light meson gas, in particular we focus on the case of a massive pion gas. Leading order results according to the chiral power-counting are presented for the DC electrical conductivity, thermal conductivity, shear viscosity, and bulk viscosity. We also comment on the possible correlation between the bulk viscosity and the trace anomaly in QCD, as well as the relation between unitarity and a minimum of the quotient $\\eta/s$ near the phase transition.

  14. Massive Gauge Fields and the Planck Scale

    E-Print Network [OSTI]

    Acosta, G D

    2004-01-01

    The present work is devoted to massive gauge fields in special relativity with two fundamental constants-the velocity of light, and the Planck length, so called doubly special relativity (DSR). The two invariant scales are accounted for by properly modified boost parameters. Within above framework we construct the vector potential as the (1/2,0)x(0,1/2) direct product, build the associated field strength tensor together with the Dirac spinors and use them to calculate various observables as functions of the Planck length.

  15. Massive Gauge Fields and the Planck Scale

    E-Print Network [OSTI]

    G. D. Acosta; M. Kirchbach

    2004-11-09

    The present work is devoted to massive gauge fields in special relativity with two fundamental constants-the velocity of light, and the Planck length, so called doubly special relativity (DSR). The two invariant scales are accounted for by properly modified boost parameters. Within above framework we construct the vector potential as the (1/2,0)x(0,1/2) direct product, build the associated field strength tensor together with the Dirac spinors and use them to calculate various observables as functions of the Planck length.

  16. Holographic superconductors from the massive gravity

    E-Print Network [OSTI]

    Hua Bi Zeng; Jian-Pin Wu

    2014-09-24

    A holographic superconductor is constructed in the background of a massive gravity theory. In the normal state without condensation, the conductivity exhibits a Drude peak that approaches a delta function in the massless gravity limit as studied by David Vegh. In the superconducting state, besides the infinite DC conductivity, the AC conductivity has Drude behavior at low frequency followed by a power law-fall. These results are in agreement with that found earlier by Horowitz and Santos, who studied a holographic superconductor with an implicit periodic potential beyond the probe limit. The results also agree with measurements on some cuprates.

  17. Broadcasting a message in a parallel computer

    DOE Patents [OSTI]

    Berg, Jeremy E. (Rochester, MN); Faraj, Ahmad A. (Rochester, MN)

    2011-08-02

    Methods, systems, and products are disclosed for broadcasting a message in a parallel computer. The parallel computer includes a plurality of compute nodes connected together using a data communications network. The data communications network optimized for point to point data communications and is characterized by at least two dimensions. The compute nodes are organized into at least one operational group of compute nodes for collective parallel operations of the parallel computer. One compute node of the operational group assigned to be a logical root. Broadcasting a message in a parallel computer includes: establishing a Hamiltonian path along all of the compute nodes in at least one plane of the data communications network and in the operational group; and broadcasting, by the logical root to the remaining compute nodes, the logical root's message along the established Hamiltonian path.

  18. PARALLEL PRESS University of WisconsinMadison Libraries

    E-Print Network [OSTI]

    Sprott, Julien Clinton

    #12;PARALLEL PRESS University of Wisconsin­Madison Libraries parallelpress.library.wisc.edu Parallel Press Catalog 2010­2011 #12;Forthcoming Books from Parallel Press John Adams: Dutiful Patriot John Method Mary Alexandra Agner For ordering information, see page 24. #12;PARALLEL PRESS 3 Parallel Press

  19. An efficient parallel set container for multicore architectures

    E-Print Network [OSTI]

    Fraguela, Basilio B.

    - tional sequential programs. The usage of parallel libraries is one of the best ways to facilitate on multicore systems. Keywords. Multicore architectures, parallel library, data containers, data parallelism 1. Motivation Parallel libraries are a good method to facilitate the expression of parallelism to pro- grammers

  20. Tempest:ASubstrateforPortableParallelProgramsSlide Tempest:ASubstratefor

    E-Print Network [OSTI]

    Lipasti, Mikko H.

    ParallelPrograms* MarkHill,JamesLarus,DavidWood WisconsinWindTunnelProject UniversityofWisconsin http:ASubstrateforPortableParallelPrograms WisconsinWindTunnelProject Slide 2 CanParallelComputingBecomeUbiquitous? ·Parallelhardwarepyramid:ASubstrateforPortableParallelPrograms WisconsinWindTunnelProject Slide 3 NotUnlessParallelSoftwareImproves ·Parallelsoftwaremorass

  1. Massive Stars in the Arches Cluster

    E-Print Network [OSTI]

    Figer, D F; Gilmore, D; Morris, M; Kim, S S; Serabyn, E; McLean, I S; Gilbert, A M; Graham, J R; Larkin, J E; Levenson, N A; Teplitz, H I; Figer, Donald F.; Najarro, Francisco; Gilmore, Diane; Morris, Mark; Kim, Sungsoo S.; Serabyn, Eugene; Lean, Ian S. Mc; Gilbert, Andrea M.; Graham, James R.; Larkin, James E.; Teplitz, Harry I.

    2002-01-01

    We present and use new spectra and narrow-band images, along with previously published broad-band images, of stars in the Arches cluster to extract photometry, astrometry, equivalent width, and velocity information. The data are interpreted with a wind/atmosphere code to determine stellar temperatures, luminosities, mass-loss rates, and abundances. We have doubled the number of known emission-line stars, and we have also made the first spectroscopic identification of the main sequence for any population in the Galactic Center. We conclude that the most massive stars are bona-fide Wolf-Rayet (WR) stars and are some of the most massive stars known, having M_{initial} > 100 Msun, and prodigious winds, Mdot > 10^{-5} Msun yr^{-1}, that are enriched with helium and nitrogen; with these identifications, the Arches cluster contains about 5% of all known WR stars in the Galaxy. We find an upper limit to the velocity dispersion of 22 kms^{-1}, implying an upper limit to the cluster mass of 7(10^4) Msun within a radius...

  2. Covariant Symplectic Structure and Conserved Charges of Topologically Massive Gravity

    E-Print Network [OSTI]

    Caner Nazaroglu; Yavuz Nutku; Bayram Tekin

    2011-06-07

    We present the covariant symplectic structure of the Topologically Massive Gravity and find a compact expression for the conserved charges of generic spacetimes with Killing symmetries.

  3. Weight Loss Regime for Massive Low Temperature Electrons | The...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weight Loss Regime for Massive Low Temperature Electrons A compound made out of ytterbium (Yb), platinum (Pt), and bismuth (Bi) offers researchers the opportunity to watch the...

  4. Locality Aware Dynamic Load Management for Massively Multiplayer Games

    E-Print Network [OSTI]

    Amza, Cristiana

    Locality Aware Dynamic Load Management for Massively Multiplayer Games Jin Chen Department with a dynamic load management algorithm enables us to better handle transient crowding by adaptively dispersing

  5. A Self Consistent Multiprocessor Space Charge Algorithm that is Almost Embarrassingly Parallel

    SciTech Connect (OSTI)

    Edward Nissen, B. Erdelyi, S.L. Manikonda

    2012-07-01

    We present a space charge code that is self consistent, massively parallelizeable, and requires very little communication between computer nodes; making the calculation almost embarrassingly parallel. This method is implemented in the code COSY Infinity where the differential algebras used in this code are important to the algorithm's proper functioning. The method works by calculating the self consistent space charge distribution using the statistical moments of the test particles, and converting them into polynomial series coefficients. These coefficients are combined with differential algebraic integrals to form the potential, and electric fields. The result is a map which contains the effects of space charge. This method allows for massive parallelization since its statistics based solver doesn't require any binning of particles, and only requires a vector containing the partial sums of the statistical moments for the different nodes to be passed. All other calculations are done independently. The resulting maps can be used to analyze the system using normal form analysis, as well as advance particles in numbers and at speeds that were previously impossible.

  6. Xyce parallel electronic simulator : users' guide.

    SciTech Connect (OSTI)

    Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Warrender, Christina E.; Keiter, Eric Richard; Pawlowski, Roger Patrick

    2011-05-01

    This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: (1) Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers; (2) Improved performance for all numerical kernels (e.g., time integrator, nonlinear and linear solvers) through state-of-the-art algorithms and novel techniques. (3) Device models which are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only); and (4) Object-oriented code design and implementation using modern coding practices that ensure that the Xyce Parallel Electronic Simulator will be maintainable and extensible far into the future. Xyce is a parallel code in the most general sense of the phrase - a message passing parallel implementation - which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows. The development of Xyce provides a platform for computational research and development aimed specifically at the needs of the Laboratory. With Xyce, Sandia has an 'in-house' capability with which both new electrical (e.g., device model development) and algorithmic (e.g., faster time-integration methods, parallel solver algorithms) research and development can be performed. As a result, Xyce is a unique electrical simulation capability, designed to meet the unique needs of the laboratory.

  7. Distributed parallel messaging for multiprocessor systems

    DOE Patents [OSTI]

    Chen, Dong; Heidelberger, Philip; Salapura, Valentina; Senger, Robert M; Steinmacher-Burrow, Burhard; Sugawara, Yutaka

    2013-06-04

    A method and apparatus for distributed parallel messaging in a parallel computing system. The apparatus includes, at each node of a multiprocessor network, multiple injection messaging engine units and reception messaging engine units, each implementing a DMA engine and each supporting both multiple packet injection into and multiple reception from a network, in parallel. The reception side of the messaging unit (MU) includes a switch interface enabling writing of data of a packet received from the network to the memory system. The transmission side of the messaging unit, includes switch interface for reading from the memory system when injecting packets into the network.

  8. Parallel path aspects of transmission modeling

    SciTech Connect (OSTI)

    Kavicky, J.A. [Argonne National Lab., IL (United States); Shahidehpour, S.M. [Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Electrical and Computer Engineering

    1996-11-01

    This paper examines the present methods and modeling techniques available to address the effects of parallel flows resulting from various firm and short-term energy transactions. A survey of significant methodologies is conducted to determine the present status of parallel flow transaction modeling. The strengths and weaknesses of these approaches are identified to suggest areas of further modeling improvements. The motivating force behind this research is to improve transfer capability assessment accuracy by suggesting a real-time modeling environment that adequately represents the influences of parallel flows while recognizing operational constraints and objectives.

  9. Competitive Parallel Disk Prefetching and Buffer Management

    E-Print Network [OSTI]

    Barve, Rakesh; Kallahalla, Mahesh; Varman, Peter J.; Vitter, Jeffrey Scott

    2000-01-01

    Competitive Parallel Disk Prefetching and Buffer Managementa0 Rakesh Barvea1 Mahesh Kallahallaa2 Peter J. Varmana2 Jeffrey Scott Vittera3 rbarve@cs.duke.edu kalla@rice.edu pjv@rice.edu jsv@cs.duke.edu Dept. of CS Dept. of ECE Dept. of ECE Dept. of CS Duke... descriptions of I/O performance metrics, lookahead models, and parallel disk configura- tions are given in section 1.1. Our parallel prefetching algorithms NOM and GREED are described 3 in section 1.2. In section 2, we discuss practical situations in which...

  10. Efficient Parallel Text Compression on GPUs 

    E-Print Network [OSTI]

    Zhang, Xiaoxi

    2012-02-14

    is the combination of LZ77 and arithmetic coding. The dictionary com- pressor produces a stream of literal symbols and phrase references, which encodes one symbol at a time by the range encoder, using a model to make a probability prediction of each bit. The GPU... with range coding. To speedup, we design and implement parallel range encoding on GPUs. Finally we copy the compressed data from device to host and output them to the compressed file. 10 CHAPTER IV PARALLEL FINDER AND MERGER A. Parallel Match Finder We...

  11. DETECTING MASSIVE GRAVITONS USING PULSAR TIMING ARRAYS

    SciTech Connect (OSTI)

    Lee, Kejia; Kramer, Michael [University of Manchester, School of Physics and Astronomy, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Manchester M13 9PL (United Kingdom); Jenet, Fredrick A.; Price, Richard H. [Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Wex, Norbert, E-mail: kjlee@mpifr-bonn.mpg.d [Max-Planck-Institut fuer Radioastronomie, Bonn 53121 (Germany)

    2010-10-20

    At the limit of weak static fields, general relativity becomes Newtonian gravity with a potential field that falls off as inverse distance rather than a theory of Yukawa-type fields with a finite range. General relativity also predicts that the speed of disturbances of its waves is c, the vacuum light speed, and is non-dispersive. For these reasons, the graviton, the boson for general relativity, can be considered to be massless. Massive gravitons, however, are features of some alternatives to general relativity. This has motivated experiments and observations that, so far, have been consistent with the zero-mass graviton of general relativity, but further tests will be valuable. A basis for new tests may be the high sensitivity gravitational wave (GW) experiments that are now being performed and the higher sensitivity experiments that are being planned. In these experiments, it should be feasible to detect low levels of dispersion due to non-zero graviton mass. One of the most promising techniques for such a detection may be the pulsar timing program that is sensitive to nano-Hertz GWs. Here, we present some details of such a detection scheme. The pulsar timing response to a GW background with the massive graviton is calculated, and the algorithm to detect the massive graviton is presented. We conclude that, with 90% probability, massless gravitons can be distinguished from gravitons heavier than 3 x 10{sup -22} eV (Compton wavelength {lambda}{sub g} = 4.1 x 10{sup 12} km), if bi-weekly observation of 60 pulsars is performed for 5 years with a pulsar rms timing accuracy of 100 ns. If 60 pulsars are observed for 10 years with the same accuracy, the detectable graviton mass is reduced to 5 x 10{sup -23} eV ({lambda}{sub g} = 2.5 x 10{sup 13} km); for 5 year observations of 100 or 300 pulsars, the sensitivity is respectively 2.5 x 10{sup -22} ({lambda}{sub g} = 5.0 x 10{sup 12} km) and 10{sup -22} eV ({lambda}{sub g} = 1.2 x 10{sup 13} km). Finally, a 10 year observation of 300 pulsars with 100 ns timing accuracy would probe graviton masses down to 3 x 10{sup -23} eV ({lambda}{sub g} = 4.1 x 10{sup 13} km).

  12. OSCAR Parallelizing Compiler Cooperative Heterogeneous Multi-core Architecture

    E-Print Network [OSTI]

    Kasahara, Hironori

    OSCAR Parallelizing Compiler Cooperative Heterogeneous Multi-core Architecture Akihiro Hayashi, powerful parallelizing compiler for hetero- geneous multi-core architectures is expected. Furthermore, cooperative work between parallelizing compiler and hetero- geneous multi-core architectures is important

  13. A Parallelizing Compiler Cooperative Heterogeneous Multicore Processor Architecture

    E-Print Network [OSTI]

    Kasahara, Hironori

    A Parallelizing Compiler Cooperative Heterogeneous Multicore Processor Architecture Yasutaka Wada and a parallelizing com- piler is important. This paper proposes a compiler cooperative hetero- geneous multicore architecture and parallelizing compilation scheme for it. Performance of the proposed scheme is evaluated

  14. Parallel problem generation for structured problems in mathematical programming 

    E-Print Network [OSTI]

    Qiang, Feng

    2015-11-26

    The aim of this research is to investigate parallel problem generation for structured optimization problems. The result of this research has produced a novel parallel model generator tool, namely the Parallel Structured ...

  15. Progress in the physics of massive neutrinos

    E-Print Network [OSTI]

    V. Barger; D. Marfatia; K. Whisnant

    2003-09-16

    The current status of the physics of massive neutrinos is reviewed with a forward-looking emphasis. The article begins with the general phenomenology of neutrino oscillations in vacuum and matter and documents the experimental evidence for oscillations of solar, reactor, atmospheric and accelerator neutrinos. Both active and sterile oscillation possibilities are considered. The impact of cosmology (BBN, CMB, leptogenesis) and astrophysics (supernovae, highest energy cosmic rays) on neutrino observables and vice versa, is evaluated. The predictions of grand unified, radiative and other models of neutrino mass are discussed. Ways of determining the unknown parameters of three-neutrino oscillations are assessed, taking into account eight-fold degeneracies in parameters that yield the same oscillation probabilities, as well as ways to determine the absolute neutrino mass scale (from beta-decay, neutrinoless double-beta decay, large scale structure and Z-bursts). Critical unknowns at present are the amplitude of \

  16. Revisiting perturbations in extended quasidilaton massive gravity

    E-Print Network [OSTI]

    Lavinia Heisenberg

    2015-04-16

    In this work we study the theory of extended quasidilaton massive gravity together with the presence of matter fields. After discussing the homogeneous and isotropic fully dynamical background equations, which governs the exact expansion history of the universe, we consider small cosmological perturbations around these general FLRW solutions. The stability of tensor, vector and scalar perturbations on top of these general background solutions give rise to slightly different constraints on the parameters of the theory than those obtained in the approximative assumption of the late-time asymptotic form of the expansion history, which does not correspond to our current epoch. This opens up the possibility of stable FLRW solutions to be compared with current data on cosmic expansion with the restricted parameter space based on theoretical ground.

  17. Revisiting perturbations in extended quasidilaton massive gravity

    E-Print Network [OSTI]

    Heisenberg, Lavinia

    2015-01-01

    In this work we study the theory of extended quasidilaton massive gravity together with the presence of matter fields. After discussing the homogeneous and isotropic fully dynamical background equations, which governs the exact expansion history of the universe, we consider small cosmological perturbations around these general FLRW solutions. The stability of tensor, vector and scalar perturbations on top of these general background solutions give rise to slightly different constraints on the parameters of the theory than those obtained in the approximative assumption of the late-time asymptotic form of the expansion history, which does not correspond to our current epoch. This opens up the possibility of stable FLRW solutions to be compared with current data on cosmic expansion with the restricted parameter space based on theoretical ground.

  18. Massive Disks in Low Surface Brightness Galaxies

    E-Print Network [OSTI]

    B. Fuchs

    2002-09-09

    An update of the set of low surface brightness galaxies is presented which can be used to set constraints on the otherwise ambiguous decompositions of their rotation curves into contributions due to the various components of the galaxies. The selected galaxies show all clear spiral structure and arguments of density wave theory of galactic spiral arms are used to estimate the masses of the galactic disks. Again these estimates seem to indicate that the disks of low surface brightness galaxies might be much more massive than currently thought. This puzzling result contradicts stellar population synthesis models. This would mean also that low surface brightness galaxies are not dominated by dark matter in their inner parts.

  19. Nonlinear parameter estimation in parallel computing environments 

    E-Print Network [OSTI]

    Li, Jie

    1996-01-01

    Paragon supercomputer. We use a two-dimensional permeability estimation problem as the example to test and demonstrate the usage of the parallel PEST. An existing simulator program called US3D, which solves the three-dimensional groudwater flow...

  20. A Communication Backend for Parallel Language Compilers

    E-Print Network [OSTI]

    Shewchuk, Jonathan

    A Communication Backend for Parallel Language Compilers James M. Stichnoth and Thomas Gross Carnegie Mellon University Abstract. Generating good communication code is an important issue for all system usually implement the communication generation routines (e.g., message buffer packing

  1. Asynchronous parallel pattern search for nonlinear optimization

    SciTech Connect (OSTI)

    P. D. Hough; T. G. Kolda; V. J. Torczon

    2000-01-01

    Parallel pattern search (PPS) can be quite useful for engineering optimization problems characterized by a small number of variables (say 10--50) and by expensive objective function evaluations such as complex simulations that take from minutes to hours to run. However, PPS, which was originally designed for execution on homogeneous and tightly-coupled parallel machine, is not well suited to the more heterogeneous, loosely-coupled, and even fault-prone parallel systems available today. Specifically, PPS is hindered by synchronization penalties and cannot recover in the event of a failure. The authors introduce a new asynchronous and fault tolerant parallel pattern search (AAPS) method and demonstrate its effectiveness on both simple test problems as well as some engineering optimization problems

  2. Circuit Optimization Using Efficient Parallel Pattern Search 

    E-Print Network [OSTI]

    Narasimhan, Srinath S.

    2011-08-08

    evaluations and difficulty in getting explicit sensitivity information make these problems intractable to standard optimization methods. We propose to explore the recently developed asynchronous parallel pattern search (APPS) method for efficient driver size...

  3. Parallel VLSI Circuit Analysis and Optimization 

    E-Print Network [OSTI]

    Ye, Xiaoji

    2012-02-14

    The prevalence of multi-core processors in recent years has introduced new opportunities and challenges to Electronic Design Automation (EDA) research and development. In this dissertation, a few parallel Very Large Scale Integration (VLSI) circuit...

  4. Feature Clustering for Accelerating Parallel Coordinate Descent

    SciTech Connect (OSTI)

    Scherrer, Chad; Tewari, Ambuj; Halappanavar, Mahantesh; Haglin, David J.

    2012-12-06

    We demonstrate an approach for accelerating calculation of the regularization path for L1 sparse logistic regression problems. We show the benefit of feature clustering as a preconditioning step for parallel block-greedy coordinate descent algorithms.

  5. Chassis Dynamometer Testing of Parallel and Series Diesel Hybrid...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Chassis Dynamometer Testing of Parallel and Series Diesel Hybrid Buses Chassis Dynamometer Testing of Parallel and Series Diesel Hybrid Buses Emissions and fuel economy data were...

  6. Building the Next Generation of Parallel Applications: Co-Design...

    Office of Scientific and Technical Information (OSTI)

    Building the Next Generation of Parallel Applications: Co-Design Opportunities and Challenges. Citation Details In-Document Search Title: Building the Next Generation of Parallel...

  7. The Manycore Revolution and Parallel Software Projects at NERSC

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Revolution and Parallel Software The Manycore Revolution and Parallel Software | Tags: Math & Computer Science PGAS.jpg Key Challenges: A new software ecosystem is expected to...

  8. HOPSPACK: Hybrid Optimization Parallel Search Package.

    SciTech Connect (OSTI)

    Gray, Genetha A.; Kolda, Tamara G.; Griffin, Joshua; Taddy, Matt; Martinez-Canales, Monica

    2008-12-01

    In this paper, we describe the technical details of HOPSPACK (Hybrid Optimization Parallel SearchPackage), a new software platform which facilitates combining multiple optimization routines into asingle, tightly-coupled, hybrid algorithm that supports parallel function evaluations. The frameworkis designed such that existing optimization source code can be easily incorporated with minimalcode modification. By maintaining the integrity of each individual solver, the strengths and codesophistication of the original optimization package are retained and exploited.4

  9. X-ray Emission from the Winds of Massive Stars

    E-Print Network [OSTI]

    Cohen, David

    X-ray Emission from the Winds of Massive Stars David Cohen Department of Physics & Astronomy-driven stellar winds are a characteristic of massive stars NGC 6888 Crescent Nebula - Tony Hallas #12;NGC 6888 Crescent Nebula - Tony Hallas O star - source of wind bubble: ~1 arc second instrumental resolution; star

  10. Graphene-enabled Wireless Communication for Massive Multicore Architectures

    E-Print Network [OSTI]

    Cabellos-Aparicio, Albert

    Graphene-enabled Wireless Communication for Massive Multicore Architectures Sergi Abadal, Eduard. This goal is feasible by using graphene-based planar antennas, which can radiate signals at the Terahertz, this is the first work that discusses the utilization of graphene-enabled wireless communication for massive

  11. Long Lived Charged Massive Particles and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Kazunori Kohri; Fumihiro Takayama

    2006-11-06

    We consider Big Bang Nucleosynthesis(BBN) with long lived charged massive particles. Before decaying, the long lived massive particles recombines with a light element to form a bound state like a hydrogen atom. We discuss the possible change of primordial light element abundances due to formations of such bound states.

  12. Graphene-enabled Wireless Communication for Massive Multicore Architectures

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    Graphene-enabled Wireless Communication for Massive Multicore Architectures Sergi Abadal, Eduard graphene-based planar antennas, which can radiate signals at the Terahertz band while utilizing lower chip that discusses the utilization of graphene-enabled wireless communication for massive multicore processors

  13. Hypervelocity binary stars: smoking gun of massive binary black holes

    E-Print Network [OSTI]

    Youjun Lu; Qingjuan Yu; D. N. C. Lin

    2007-07-22

    The hypervelocity stars recently found in the Galactic halo are expelled from the Galactic center through interactions between binary stars and the central massive black hole or between single stars and a hypothetical massive binary black hole. In this paper, we demonstrate that binary stars can be ejected out of the Galactic center with velocities up to 10^3 km/s, while preserving their integrity, through interactions with a massive binary black hole. Binary stars are unlikely to attain such high velocities via scattering by a single massive black hole or through any other mechanisms. Based on the above theoretical prediction, we propose a search for binary systems among the hypervelocity stars. Discovery of hypervelocity binary stars, even one, is a definitive evidence of the existence of a massive binary black hole in the Galactic center.

  14. Parallel phase model : a programming model for high-end parallel machines with manycores.

    SciTech Connect (OSTI)

    Wu, Junfeng (Syracuse University, Syracuse, NY); Wen, Zhaofang; Heroux, Michael Allen; Brightwell, Ronald Brian

    2009-04-01

    This paper presents a parallel programming model, Parallel Phase Model (PPM), for next-generation high-end parallel machines based on a distributed memory architecture consisting of a networked cluster of nodes with a large number of cores on each node. PPM has a unified high-level programming abstraction that facilitates the design and implementation of parallel algorithms to exploit both the parallelism of the many cores and the parallelism at the cluster level. The programming abstraction will be suitable for expressing both fine-grained and coarse-grained parallelism. It includes a few high-level parallel programming language constructs that can be added as an extension to an existing (sequential or parallel) programming language such as C; and the implementation of PPM also includes a light-weight runtime library that runs on top of an existing network communication software layer (e.g. MPI). Design philosophy of PPM and details of the programming abstraction are also presented. Several unstructured applications that inherently require high-volume random fine-grained data accesses have been implemented in PPM with very promising results.

  15. Proc. of IEEE Int. Conf. on Robotics and Automation, San Diego, CA, May 1994. Sensorless Manipulation Using Massively Parallel

    E-Print Network [OSTI]

    Richardson, David

    Proc. of IEEE Int. Conf. on Robotics and Automation, San Diego, CA, May 1994. Sensorless, and Industrial Affiliates. air­bag sensor is commercially available [1]; video pro­ jections using an integrated

  16. A modular neural interface for massively parallel recording and control : subsystem design considerations for research and clinical applications

    E-Print Network [OSTI]

    Wentz, Christian T

    2010-01-01

    The closed-loop Brain-Machine Interface (BMI) has long been a dream for clinicians and neuroscience researchers alike - that is, the ability to extract meaningful information from the brain, perform computation on this ...

  17. On Massively Parallel Simulation of Large-Scale Fat-Tree Networks for HPC Systems and Data Centers

    E-Print Network [OSTI]

    Sun, Xian-He

    Technologies (WEST), USA, June 2011. [4] N. Liu, X. Yang, X.-H. Sun, J. Jenkins, and R. Ross. Yarnsim://www.alcf.anl.gov/user-guides/mira-cetus-vesta Department of Computer Science, Illinois Institute of Technology, Chicago, Illinois.Ning Liu, Xian-He Sun statistic collector protocols routing algorithms simulated nodes 0% 20% 40% 60% 80% 100% 0 50 100 150 200

  18. Massively Parallel Microfluidic Cell-Pairing Platform for the Statistical Study of Immunological Cell-Cell Interactions

    E-Print Network [OSTI]

    Hoehl, Melanie Margarete

    Variability in cell-cell interactions is ubiquitous and particularly relevant for the immune system, where the reliability of cell-cell interactions is critical for the prevention of disease. This variability is poorly ...

  19. Characterizing the Separation and Reattachment of Suction Surface Boundary Layer in Low Pressure Turbine Using Massively Parallel Large Eddy Simulations 

    E-Print Network [OSTI]

    Jagannathan, Shriram

    2012-02-14

    The separation and reattachment of the suction surface boundary layer in a low pressure turbine is characterized using large-eddy simulation at Re=68,000 based on freestream velocity and suction surface length. A high pass filtered Smagorinsky model...

  20. Massively Multi-core Acceleration of a Document-Similarity Classifier to Detect Web Attacks

    SciTech Connect (OSTI)

    Ulmer, C; Gokhale, M; Top, P; Gallagher, B; Eliassi-Rad, T

    2010-01-14

    This paper describes our approach to adapting a text document similarity classifier based on the Term Frequency Inverse Document Frequency (TFIDF) metric to two massively multi-core hardware platforms. The TFIDF classifier is used to detect web attacks in HTTP data. In our parallel hardware approaches, we design streaming, real time classifiers by simplifying the sequential algorithm and manipulating the classifier's model to allow decision information to be represented compactly. Parallel implementations on the Tilera 64-core System on Chip and the Xilinx Virtex 5-LX FPGA are presented. For the Tilera, we employ a reduced state machine to recognize dictionary terms without requiring explicit tokenization, and achieve throughput of 37MB/s at slightly reduced accuracy. For the FPGA, we have developed a set of software tools to help automate the process of converting training data to synthesizable hardware and to provide a means of trading off between accuracy and resource utilization. The Xilinx Virtex 5-LX implementation requires 0.2% of the memory used by the original algorithm. At 166MB/s (80X the software) the hardware implementation is able to achieve Gigabit network throughput at the same accuracy as the original algorithm.

  1. IBM Parallel Environment for Linux Operation and Use

    E-Print Network [OSTI]

    Hickman, Mark

    IBM Parallel Environment for Linux Operation and Use Using the Parallel Operating Environment Version 4 Release 2 SA23-2217-00 #12;#12;IBM Parallel Environment for Linux Operation and Use Using) This edition applies to version 4, release 2, modification 0 of IBM Parallel Environment for Linux (product

  2. Tempest:ASubstrateforPortableParallelProgramsSlide Tempest:ASubstratefor

    E-Print Network [OSTI]

    Lipasti, Mikko H.

    ParallelPrograms* MarkHill,JamesLarus,DavidWood WisconsinWindTunnelProject UniversityofWisconsin http:ASubstrateforPortableParallelPrograms WisconsinWindTunnelProject Slide 2 CanParallelComputingBecomeUbiquitous? ·Parallelhardwarepyramid;Tempest:ASubstrateforPortableParallelPrograms WisconsinWindTunnelProject Slide 3 Not

  3. MACHO (MAssive Compact Halo Objects) Data

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The primary aim of the MACHO Project is to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it is necessary to monitor photometrically several million stars for a period of years in order to obtain a useful detection rate. For this purpose MACHO has a two channel system that employs eight CCDs, mounted on the 50 inch telescope at Mt. Stromlo. The high data rate (several GBytes per night) is accommodated by custom electronics and on-line data reduction. The Project has taken more than 27,000 images with this system since June 1992. Analysis of a subset of these data has yielded databases containing light curves in two colors for 8 million stars in the LMC and 10 million in the bulge of the Milky Way. A search for microlensing has turned up four candidates toward the Large Magellanic Cloud and 45 toward the Galactic Bulge. The web page for data provides links to MACHO Project data portals and various specialized interfaces for viewing or searching the data. (Specialized Interface)

  4. Dark aspects of massive spinor electrodynamics

    SciTech Connect (OSTI)

    Kim, Edward J.; Kouwn, Seyen; Oh, Phillial; Park, Chan-Gyung E-mail: seyen@ewha.ac.kr E-mail: parkc@jbnu.ac.kr

    2014-07-01

    We investigate the cosmology of massive spinor electrodynamics when torsion is non-vanishing. A non-minimal interaction is introduced between the torsion and the vector field and the coupling constant between them plays an important role in subsequential cosmology. It is shown that the mass of the vector field and torsion conspire to generate dark energy and pressureless dark matter, and for generic values of the coupling constant, the theory effectively provides an interacting model between them with an additional energy density of the form ? 1/a{sup 6}. The evolution equations mimic ?CDM behavior up to 1/a{sup 3} term and the additional term represents a deviation from ?CDM. We show that the deviation is compatible with the observational data, if it is very small. We find that the non-minimal interaction is responsible for generating an effective cosmological constant which is directly proportional to the mass squared of the vector field and the mass of the photon within its current observational limit could be the source of the dark energy.

  5. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

    2013-11-12

    Data communications in a parallel active messaging interface (`PAMI`) of a parallel computer composed of compute nodes that execute a parallel application, each compute node including application processors that execute the parallel application and at least one management processor dedicated to gathering information regarding data communications. The PAMI is composed of data communications endpoints, each endpoint composed of a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, the compute nodes and the endpoints coupled for data communications through the PAMI and through data communications resources. Embodiments function by gathering call site statistics describing data communications resulting from execution of data communications instructions and identifying in dependence upon the call cite statistics a data communications algorithm for use in executing a data communications instruction at a call site in the parallel application.

  6. Asymptotic symmetries of gravity and soft theorems for massive particles

    E-Print Network [OSTI]

    Campiglia, Miguel

    2015-01-01

    The existing equivalence between (generalized) BMS Ward identities with leading and subleading soft graviton theorems is extended to the case where the scattering particles are massive scalars. By extending the action of generalized BMS group off null infinity at late times, we show that there is a natural action of such group not only on the radiative data at null infinity but also on the scattering data of the massive scalar field. This leads to a formulation of Ward identities associated to the generalized BMS group when the scattering states are massive scalars or massless gravitons and we show that these Ward identities are equivalent to the leading and subleading soft graviton theorems.

  7. (Sub-)mm interferometry in massive star-forming regions

    E-Print Network [OSTI]

    H. Beuther

    2003-08-21

    (Sub-)mm interferometry is the most favorable technique to investigate the earliest stages of massive star formation. I will outline general applications in that field and discuss results of different sub-topics (hot core chemistry and massive molecular outflows). Furthermore, recent data obtained with the Submillimeter Array will be shown to present the unique capabilities of this new instrument. Finally, I will give a short outlook on the main physical topics of massive star formation to be tackled with (sub-)mm interferometry within the next decade.

  8. Massive gravity as a limit of bimetric gravity

    E-Print Network [OSTI]

    Martin-Moruno, Prado; Visser, Matt

    2013-01-01

    Massive gravity may be viewed as a suitable limit of bimetric gravity. The limiting procedure can lead to an interesting interplay between the "background" and "foreground" metrics in a cosmological context. The fact that in bimetric theories one always has two sets of metric equations of motion continues to have an effect even in the massive gravity limit. Thus, solutions of bimetric gravity in the limit of vanishing kinetic term are also solutions of massive gravity, but the contrary statement is not necessarily true.

  9. 18.337J / 6.338J Applied Parallel Computing (SMA 5505), Spring 2005

    E-Print Network [OSTI]

    Edelman, Alan

    Applied Parallel Computing is an advanced interdisciplinary introduction to applied parallel computing on modern supercomputers.

  10. Parallel Transport on Principal Bundles over Stacks

    E-Print Network [OSTI]

    Brian Collier; Eugene Lerman; Seth Wolbert

    2015-09-16

    In this paper we introduce a notion of parallel transport for principal bundles with connections over differentiable stacks. We show that principal bundles with connections over stacks can be recovered from their parallel transport thereby extending the results of Barrett, Caetano and Picken, and Schreiber and Waldof from manifolds to stacks. In the process of proving our main result we simplify Schreiber and Waldorf's definition of a transport functor for principal bundles with connections over manifolds and provide a more direct proof of the correspondence between principal bundles with connections and transport functors.

  11. Parallel Implementation of Power System Dynamic Simulation

    SciTech Connect (OSTI)

    Jin, Shuangshuang; Huang, Zhenyu; Diao, Ruisheng; Wu, Di; Chen, Yousu

    2013-07-21

    Dynamic simulation of power system transient stability is important for planning, monitoring, operation, and control of electrical power systems. However, modeling the system dynamics and network involves the computationally intensive time-domain solution of numerous differential and algebraic equations (DAE). This results in a transient stability implementation that may not maintain the real-time constraints of an online security assessment. This paper presents a parallel implementation of the dynamic simulation on a high-performance computing (HPC) platform using parallel simulation algorithms and computation architectures. It enables the simulation to run even faster than real time, enabling the “look-ahead” capability of upcoming stability problems in the power grid.

  12. Regional weather modeling on parallel computers.

    SciTech Connect (OSTI)

    Baillie, C.; Michalakes, J.; Skalin, R.; Mathematics and Computer Science; NOAA Forecast Systems Lab.; Norwegian Meteorological Inst.

    1997-01-01

    This special issue on 'regional weather models' complements the October 1995 special issue on 'climate and weather modeling', which focused on global models. In this introduction we review the similarities and differences between regional and global atmospheric models. Next, the structure of regional models is described and we consider how the basic algorithms applied in these models influence the parallelization strategy. Finally, we give a brief overview of the eight articles in this issue and discuss some remaining challenges in the area of adapting regional weather models to parallel computers.

  13. Parallel I/O in Practice

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesseworkSURVEYI/O Streams forOrhanTheoreticalSecurityParallel I/O Parallel I/O

  14. SEGUE 2: THE LEAST MASSIVE GALAXY

    SciTech Connect (OSTI)

    Kirby, Evan N.; Boylan-Kolchin, Michael; Bullock, James S.; Kaplinghat, Manoj; Cohen, Judith G.; Geha, Marla

    2013-06-10

    Segue 2, discovered by Belokurov et al., is a galaxy with a luminosity of only 900 L{sub Sun }. We present Keck/DEIMOS spectroscopy of 25 members of Segue 2-a threefold increase in spectroscopic sample size. The velocity dispersion is too small to be measured with our data. The upper limit with 90% (95%) confidence is {sigma}{sub v} < 2.2 (2.6) km s{sup -1}, the most stringent limit for any galaxy. The corresponding limit on the mass within the three-dimensional half-light radius (46 pc) is M{sub 1/2} < 1.5 (2.1) Multiplication-Sign 10{sup 5} M{sub Sun }. Segue 2 is the least massive galaxy known. We identify Segue 2 as a galaxy rather than a star cluster based on the wide dispersion in [Fe/H] (from -2.85 to -1.33) among the member stars. The stars' [{alpha}/Fe] ratios decline with increasing [Fe/H], indicating that Segue 2 retained Type Ia supernova ejecta despite its presently small mass and that star formation lasted for at least 100 Myr. The mean metallicity, ([Fe/H]) = -2.22 {+-} 0.13 (about the same as the Ursa Minor galaxy, 330 times more luminous than Segue 2), is higher than expected from the luminosity-metallicity relation defined by more luminous dwarf galaxy satellites of the Milky Way. Segue 2 may be the barest remnant of a tidally stripped, Ursa Minor-sized galaxy. If so, it is the best example of an ultra-faint dwarf galaxy that came to be ultra-faint through tidal stripping. Alternatively, Segue 2 could have been born in a very low mass dark matter subhalo (v{sub max} < 10 km s{sup -1}), below the atomic hydrogen cooling limit.

  15. Asymptotically anti-de Sitter spacetimes in topologically massive gravity

    E-Print Network [OSTI]

    Marc Henneaux; Cristian Martinez; Ricardo Troncoso

    2009-03-31

    We consider asymptotically anti-de Sitter spacetimes in three-dimensional topologically massive gravity with a negative cosmological constant, for all values of the mass parameter $\\mu$ ($\\mu\

  16. Mastery and the mobile future of massively multiplayer games

    E-Print Network [OSTI]

    Roy, Daniel, S.M. Massachusetts Institute of Technology

    2007-01-01

    What game design opportunities do we create when we extend massively multiplayer online games (MMOs) to cell phones? MMOs allow us to create representations of our own increasing mastery, and mobile gives us better access ...

  17. A Survey of Extended H$_2$ Emission from Massive YSOs

    E-Print Network [OSTI]

    Navarete, Felipe; Barbosa, Cassio L; Blum, Robert D

    2015-01-01

    We present the results from a survey, designed to investigate the accretion process of massive young stellar objects (MYSOs) through near infrared narrow band imaging using the H$_2$ $\

  18. AFL-1: A Programming Language for Massively Concurrent Computers

    E-Print Network [OSTI]

    Blelloch, Guy

    1986-11-01

    Computational models are arising is which programs are constructed by specifying large networks of very simple computational devices. Although such models can potentially make use of a massive amount of concurrency, ...

  19. Power-Demand Routing in massive geo-distributed systems

    E-Print Network [OSTI]

    Qureshi, Asfandyar

    2010-01-01

    There is an increasing trend toward massive, geographically distributed systems. The largest Internet companies operate hundreds of thousands of servers in multiple geographic locations, and are growing at a fast clip. A ...

  20. Monumental effort: How a dedicated team completed a massive beam...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    its cleaned and refurbished components out of the TFTR area and into the NSTX-U test cell next door. But how do you get something so massive to budge? The Beam Team solved the...

  1. An alternative derivation of the Minimal massive 3D gravity

    E-Print Network [OSTI]

    Ahmet Baykal

    2014-12-23

    By using the algebra of exterior forms and the first order formalism with constraints, an alternative derivation of the field equations for the Minimal massive 3D gravity model is presented.

  2. Interactions with quadratic dependence on string-localized massive vectormesons: massive scalar quantum electrodynamics

    E-Print Network [OSTI]

    Bert Schroer

    2014-08-27

    Wigner's famous 1939 classification of positive energy representations, combined with the more recent modular localization principle, has led to a significant conceptual and computational extension of renormalized perturbation theory to interactions involving fields of higher spin s>1/2. The starting observation was that the well-known clash between point-localized gauge theories and the Hilbert space, which hitherto has been solved by using a Krein space setting, can also be solved by preserving the Hilbert space setting; in this case the theory selects the tightest covariant localization which is consistent with the Hilbert space positivity. The resulting semiinfinite spacelike string-localization for all (m=0,s>1/2) representations does not only lead to a new insight into the origin of infrared problems (including confinement), but also improves the short-distance behavior of massive s>1/2 fields to the extend that the power-counting criterion admits candidates for renormalizable interactions for arbitrary high spins. In this work the new situation is exemplified for the interaction of massive vectormesons with scalar charged- and neutral- (Higgs) matter, for which the new "adiabatic equivalence principle" leads to a local relation between a renormalizable stringlike and a nonrenormalizable (but nevertheless finite-parametric) pointlike interaction.

  3. Massive Gravity from Higher Derivative Gravity with Boundary Conditions

    E-Print Network [OSTI]

    Minjoon Park; Lorenzo Sorbo

    2012-10-29

    With an appropriate choice of parameters, a higher derivative theory of gravity can describe a normal massive sector and a ghost massless sector. We show that, when defined on an asymptotically de Sitter spacetime with Dirichlet boundary conditions, such a higher derivative gravity can provide a framework for a unitary theory of massive gravity in four spacetime dimensions. The resulting theory is free not only of higher derivative ghosts but also of the Boulware-Deser mode.

  4. On the Hamiltonian form of 3D massive gravity

    E-Print Network [OSTI]

    Olaf Hohm; Alasdair Routh; Paul K. Townsend; Baocheng Zhang

    2012-09-14

    We present a "Chern-Simons-like" action for the "general massive gravity" model propagating two spin-2 modes with independent masses in three spacetime dimensions (3D), and we use it to find a simple Hamiltonian form of this model. The number of local degrees of freedom, determined by the dimension of the physical phase space, agrees with a linearized analysis except in some limits, in particular that yielding "new topologically massive gravity", which therefore suffers from a linearization instability.

  5. A Pervasive Parallel Processing Framework For Data Visualization And Analysis At Extreme Scale Final Scientific and Technical Report

    SciTech Connect (OSTI)

    Geveci, Berk

    2014-10-31

    The evolution of the computing world from teraflop to petaflop has been relatively effortless,with several of the existing programming models scaling effectively to the petascale. The migration to exascale, however, poses considerable challenges. All industry trends infer that the exascale machine will be built using processors containing hundreds to thousands of cores per chip. It can be inferred that efficient concurrency on exascale machines requires a massive amount of concurrent threads, each performing many operations on a localized piece of data. Currently, visualization libraries and applications are based off what is known as the visualization pipeline. In the pipeline model, algorithms are encapsulated as filters with inputs and outputs. These filters are connected by setting the output of one component to the input of another. Parallelism in the visualization pipeline is achieved by replicating the pipeline for each processing thread. This works well for today’s distributed memory parallel computers but cannot be sustained when operating on processors with thousands of cores. Our project investigates a new visualization framework designed to exhibit the pervasive parallelism necessary for extreme scale machines. Our framework achieves this by defining algorithms in terms of worklets, which are localized stateless operations. Worklets are atomic operations that execute when invoked unlike filters, which execute when a pipeline request occurs. The worklet design allows execution on a massive amount of lightweight threads with minimal overhead. Only with such fine-grained parallelism can we hope to fill the billions of threads we expect will be necessary for efficient computation on an exascale machine.

  6. CHAPTER 30 (in old edition) Parallel Algorithms

    E-Print Network [OSTI]

    Dragan, Feodor F.

    for Parallel Random Access Machine ­ Consists of p processors (PEs), P0, P1, P2, ... , Pp-1 connected can be assumed to be either synchronous or asynchronous. · When synchronous, all operations (e to be added to perform the required data movement on real machines. ­ However, the constant-time global data

  7. Automatic Loop Parallelization via Compiler Guided Refactoring

    E-Print Network [OSTI]

    . Lyngby, Denmark Email: {pl,ska}@imm.dtu.dk Computer Science Engineering Chalmers U. Technology, 412 96 by the computing industry today. Yet, applications are often written in ways that prevent automatic parallelization Gothenburg, Sweden Email: lidman@student.chalmers.se, mckee@chalmers.se IBM Haifa Research Labs Mount Carmel

  8. Parallel programming with PCN. Revision 2

    SciTech Connect (OSTI)

    Foster, I.; Tuecke, S.

    1993-01-01

    PCN is a system for developing and executing parallel programs. It comprises a high-level programming language, tools for developing and debugging programs in this language, and interfaces to Fortran and Cthat allow the reuse of existing code in multilingual parallel programs. Programs developed using PCN are portable across many different workstations, networks, and parallel computers. This document provides all the information required to develop parallel programs with the PCN programming system. It includes both tutorial and reference material. It also presents the basic concepts that underlie PCN, particularly where these are likely to be unfamiliar to the reader, and provides pointers to other documentation on the PCN language, programming techniques, and tools. PCN is in the public domain. The latest version of both the software and this manual can be obtained by anonymous ftp from Argonne National Laboratory in the directory pub/pcn at info.mcs. ani.gov (cf. Appendix A). This version of this document describes PCN version 2.0, a major revision of the PCN programming system. It supersedes earlier versions of this report.

  9. Message passing with parallel queue traversal

    DOE Patents [OSTI]

    Underwood, Keith D. (Albuquerque, NM); Brightwell, Ronald B. (Albuquerque, NM); Hemmert, K. Scott (Albuquerque, NM)

    2012-05-01

    In message passing implementations, associative matching structures are used to permit list entries to be searched in parallel fashion, thereby avoiding the delay of linear list traversal. List management capabilities are provided to support list entry turnover semantics and priority ordering semantics.

  10. Parallel Performance of a Combustion Chemistry Simulation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Skinner, Gregg; Eigenmann, Rudolf

    1995-01-01

    We used a description of a combustion simulation's mathematical and computational methods to develop a version for parallel execution. The result was a reasonable performance improvement on small numbers of processors. We applied several important programming techniques, which we describe, in optimizing the application. This work has implications for programming languages, compiler design, and software engineering.

  11. Parallel Programming for High-Performance Applications

    E-Print Network [OSTI]

    Bal, Henri E.

    into a rather dull and routine occupation'' · S. Gill, Computer Journal, 1958 #12;Why do we need parallel important #12;Moore's law (1975) · Circuit complexity doubles every 18 months · Exponential transistor machines (Blue Gene) · 2000s: grid computing: combining resources world- wide (Globus) · Now: multicores

  12. Pictorial Representation of Parallel Programs Susan Stepney

    E-Print Network [OSTI]

    Stepney, Susan

    of its tools, GRAIL. 1 Introduction Parallel programs have considerably more complicated structures than been developed as part of the Alvey ParSiFal project, for use by one of its tools, GRAIL [1 design. 3 Two-Dimensional Display The pictorial representation used in GRAIL is two dimensional

  13. Parallelism for quantum computation with qudits

    SciTech Connect (OSTI)

    O'Leary, Dianne P. [Department of Computer Science and Institute for Advanced Computer Studies, University of Maryland, College Park, Maryland 20742, USA and Mathematical and Computational Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); IDA Center for Computing Sciences, 17100 Science Drive, Bowie, Maryland 20715-4300 (United States); Brennen, Gavin K. [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020, Innsbruck (Austria); Bullock, Stephen S. [IDA Center for Computing Sciences, 17100 Science Drive, Bowie, Maryland 20715-4300 (United States)

    2006-09-15

    Robust quantum computation with d-level quantum systems (qudits) poses two requirements: fast, parallel quantum gates and high-fidelity two-qudit gates. We first describe how to implement parallel single-qudit operations. It is by now well known that any single-qudit unitary can be decomposed into a sequence of Givens rotations on two-dimensional subspaces of the qudit state space. Using a coupling graph to represent physically allowed couplings between pairs of qudit states, we then show that the logical depth (time) of the parallel gate sequence is equal to the height of an associated tree. The implementation of a given unitary can then optimize the tradeoff between gate time and resources used. These ideas are illustrated for qudits encoded in the ground hyperfine states of the alkali-metal atoms {sup 87}Rb and {sup 133}Cs. Second, we provide a protocol for implementing parallelized nonlocal two-qudit gates using the assistance of entangled qubit pairs. Using known protocols for qubit entanglement purification, this offers the possibility of high-fidelity two-qudit gates.

  14. PARALLEL MATRIX MULTIPLICATION: A SYSTEMATIC JOURNEY

    E-Print Network [OSTI]

    Batory, Don

    PARALLEL MATRIX MULTIPLICATION: A SYSTEMATIC JOURNEY MARTIN D. SCHATZ, ROBERT A. VAN DE GEIJN- trix matrix multiplication algorithms. The journey starts with a description of how matrices implementation of matrix-vector multiplication and rank-1 update, continues on to reveal a fam- ily of matrix-matrix

  15. Effecting Parallel Graph Eigensolvers Through Library Composition

    E-Print Network [OSTI]

    Lumsdaine, Andrew

    is not possible in general. Conventional linear algebra libraries cannot operate on graph data types. Likewise exploitation of this duality. Graph libraries and matrix libraries use different data types, and despiteEffecting Parallel Graph Eigensolvers Through Library Composition Alex Breuer, Peter Gottschling

  16. WEBPIE: A WEB-SCALE PARALLEL INFERENCE

    E-Print Network [OSTI]

    WEBPIE: A WEB-SCALE PARALLEL INFERENCE ENGINE Jacopo Urbani, Spyros Kotoulas, Jason Maassen, Niels Amsterdam Monday 10 May 2010 #12;The Semantic Web The Semantic Web is an extension of the current Web where the semantics is defined Basically the idea is to move from Web of Documents (Traditional Web) Web of data

  17. Non-thermal emission processes in massive binaries

    E-Print Network [OSTI]

    M. De Becker

    2007-09-26

    In this paper, I present a general discussion of several astrophysical processes likely to play a role in the production of non-thermal emission in massive stars, with emphasis on massive binaries. Even though the discussion will start in the radio domain where the non-thermal emission was first detected, the census of physical processes involved in the non-thermal emission from massive stars shows that many spectral domains are concerned, from the radio to the very high energies. First, the theoretical aspects of the non-thermal emission from early-type stars will be addressed. The main topics that will be discussed are respectively the physics of individual stellar winds and their interaction in binary systems, the acceleration of relativistic electrons, the magnetic field of massive stars, and finally the non-thermal emission processes relevant to the case of massive stars. Second, this general qualitative discussion will be followed by a more quantitative one, devoted to the most probable scenario where non-thermal radio emitters are massive binaries. I will show how several stellar, wind and orbital parameters can be combined in order to make some semi-quantitative predictions on the high-energy counterpart to the non-thermal emission detected in the radio domain. These theoretical considerations will be followed by a census of results obtained so far, and related to this topic... (see paper for full abstract)

  18. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

    2014-02-11

    Data communications in a parallel active messaging interface ('PAMI') or a parallel computer, the parallel computer including a plurality of compute nodes that execute a parallel application, the PAMI composed of data communications endpoints, each endpoint including a specification of data communications parameters for a thread of execution of a compute node, including specification of a client, a context, and a task, the compute nodes and the endpoints coupled for data communications instruction, the instruction characterized by instruction type, the instruction specifying a transmission of transfer data from the origin endpoint to a target endpoint and transmitting, in accordance witht the instruction type, the transfer data from the origin endpoin to the target endpoint.

  19. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

    2013-10-29

    Data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the parallel computer including a plurality of compute nodes that execute a parallel application, the PAMI composed of data communications endpoints, each endpoint including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, the compute nodes and the endpoints coupled for data communications through the PAMI and through data communications resources, including receiving in an origin endpoint of the PAMI a data communications instruction, the instruction characterized by an instruction type, the instruction specifying a transmission of transfer data from the origin endpoint to a target endpoint and transmitting, in accordance with the instruction type, the transfer data from the origin endpoint to the target endpoint.

  20. VIP-FS: A Virtual, Parallel file System for High Performance Parallel and Distributed Computing *

    E-Print Network [OSTI]

    -passing li- blclries only provide part of the support necessary for most high performan.ce distributed computing applzca- tzcjns - support for hagh speed parallel l/O is still lark- 211q. In this paper, we

  1. Massive Gas Injection Experiments at JET – Performance and Characterisation of the Disruption Mitigation Valve

    E-Print Network [OSTI]

    Massive Gas Injection Experiments at JET – Performance and Characterisation of the Disruption Mitigation Valve

  2. New Techniques and Technologies for Information Retrieval and Knowledge Extraction from Nuclear Fusion Massive Databases

    E-Print Network [OSTI]

    New Techniques and Technologies for Information Retrieval and Knowledge Extraction from Nuclear Fusion Massive Databases

  3. Adaptive parallelism mapping in dynamic environments using machine learning 

    E-Print Network [OSTI]

    Emani, Murali Krishna

    2015-06-29

    Modern day hardware platforms are parallel and diverse, ranging from mobiles to data centers. Mainstream parallel applications execute in the same system competing for resources. This resource contention may lead to a ...

  4. Frame: An Imperative Coordination Language for Parallel Programming 

    E-Print Network [OSTI]

    Cole, Murray

    2000-01-01

    We present Frame, a simple language which facilitates structured expression of imperative parallelism. Programs are described at two levels. The top level captures the main parallel algorithmic structure (which may be nested) and is independent...

  5. Characterizing the parallelism in rule-based expert systems

    SciTech Connect (OSTI)

    Douglass, R.J.

    1984-01-01

    A brief review of two classes of rule-based expert systems is presented, followed by a detailed analysis of potential sources of parallelism at the production or rule level, the subrule level (including match, select, and act parallelism), and at the search level (including AND, OR, and stream parallelism). The potential amount of parallelism from each source is discussed and characterized in terms of its granularity, inherent serial constraints, efficiency, speedup, dynamic behavior, and communication volume, frequency, and topology. Subrule parallelism will yield, at best, two- to tenfold speedup, and rule level parallelism will yield a modest speedup on the order of 5 to 10 times. Rule level can be combined with OR, AND, and stream parallelism in many instances to yield further parallel speedups.

  6. Kalman Filter Tracking on Parallel Architectures

    E-Print Network [OSTI]

    Cerati, Giuseppe; Lantz, Steven; McDermott, Kevin; Riley, Dan; Tadel, Matevž; Wittich, Peter; Würthwein, Frank; Yagil, Avi

    2015-01-01

    Power density constraints are limiting the performance improvements of modern CPUs. To address this we have seen the introduction of lower-power, multi-core processors, but the future will be even more exciting. In order to stay within the power density limits but still obtain Moore's Law performance/price gains, it will be necessary to parallelize algorithms to exploit larger numbers of lightweight cores and specialized functions like large vector units. Example technologies today include Intel's Xeon Phi and GPGPUs. Track finding and fitting is one of the most computationally challenging problems for event reconstruction in particle physics. At the High Luminosity LHC, for example, this will be by far the dominant problem. The need for greater parallelism has driven investigations of very different track finding techniques including Cellular Automata or returning to Hough Transform. The most common track finding techniques in use today are however those based on the Kalman Filter. Significant experience has...

  7. Locating hardware faults in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

    2010-04-13

    Locating hardware faults in a parallel computer, including defining within a tree network of the parallel computer two or more sets of non-overlapping test levels of compute nodes of the network that together include all the data communications links of the network, each non-overlapping test level comprising two or more adjacent tiers of the tree; defining test cells within each non-overlapping test level, each test cell comprising a subtree of the tree including a subtree root compute node and all descendant compute nodes of the subtree root compute node within a non-overlapping test level; performing, separately on each set of non-overlapping test levels, an uplink test on all test cells in a set of non-overlapping test levels; and performing, separately from the uplink tests and separately on each set of non-overlapping test levels, a downlink test on all test cells in a set of non-overlapping test levels.

  8. Parallel machine architecture for production rule systems

    DOE Patents [OSTI]

    Allen, Jr., John D. (Knoxville, TN); Butler, Philip L. (Knoxville, TN)

    1989-01-01

    A parallel processing system for production rule programs utilizes a host processor for storing production rule right hand sides (RHS) and a plurality of rule processors for storing left hand sides (LHS). The rule processors operate in parallel in the recognize phase of the system recognize -Act Cycle to match their respective LHS's against a stored list of working memory elements (WME) in order to find a self consistent set of WME's. The list of WME is dynamically varied during the Act phase of the system in which the host executes or fires rule RHS's for those rules for which a self-consistent set has been found by the rule processors. The host transmits instructions for creating or deleting working memory elements as dictated by the rule firings until the rule processors are unable to find any further self-consistent working memory element sets at which time the production rule system is halted.

  9. Stochastic Particle Acceleration in Parallel Relativistic Shocks

    E-Print Network [OSTI]

    Joni J. P. Virtanen; Rami Vainio

    2005-03-03

    We present results of test-particle simulations on both the first- and the second-order Fermi acceleration for relativistic parallel shock waves. Our studies suggest that the role of the second-order mechanism in the turbulent downstream of a relativistic shock may have been underestimated in the past, and that the stochastic mechanism may have significant effects on the form of the particle spectra and its time evolution.

  10. Parallel Exact Inference Yinglong Xia1

    E-Print Network [OSTI]

    Hwang, Kai

    using p processors, we show an execution time of O(nk2 m + n2w + (nw2 + wN log n + rwwN + rwN log N)/p of the classical technique of converting a Bayesian network to a junction tree before computing inference. We propose a parallel algorithm for constructing potential ta- bles for a junction tree and explore

  11. Alexandru Iosup Parallel and Distributed Systems Group

    E-Print Network [OSTI]

    Langendoen, Koen

    ­ the Netherlands ­ Europe founded 13th century pop: 100,000 pop.: 100,000 pop: 16.5 M pop: 100,000 founded 1842 pop: 13,000 pop.: 100,000 (We are here) #12;The Parallel and Distributed Systems Group at TU Delft Johan Challenges and High Quality Time ­ A. Iosup 5 #12;Online Gaming used to be art, may now be computing

  12. Parallel Heuristics for Scalable Community Detection

    SciTech Connect (OSTI)

    Lu, Howard; Kalyanaraman, Anantharaman; Halappanavar, Mahantesh; Choudhury, Sutanay

    2014-05-17

    Community detection has become a fundamental operation in numerous graph-theoretic applications. It is used to reveal natural divisions that exist within real world networks without imposing prior size or cardinality constraints on the set of communities. Despite its potential for application, there is only limited support for community detection on large-scale parallel computers, largely owing to the irregular and inherently sequential nature of the underlying heuristics. In this paper, we present parallelization heuristics for fast community detection using the Louvain method as the serial template. The Louvain method is an iterative heuristic for modularity optimization. Originally developed by Blondel et al. in 2008, the method has become increasingly popular owing to its ability to detect high modularity community partitions in a fast and memory-efficient manner. However, the method is also inherently sequential, thereby limiting its scalability to problems that can be solved on desktops. Here, we observe certain key properties of this method that present challenges for its parallelization, and consequently propose multiple heuristics that are designed to break the sequential barrier. Our heuristics are agnostic to the underlying parallel architecture. For evaluation purposes, we implemented our heuristics on shared memory (OpenMP) and distributed memory (MapReduce-MPI) machines, and tested them over real world graphs derived from multiple application domains (internet, biological, natural language processing). Experimental results demonstrate the ability of our heuristics to converge to high modularity solutions comparable to those output by the serial algorithm in nearly the same number of iterations, while also drastically reducing time to solution.

  13. Cosmological stability bound in massive gravity and bigravity

    SciTech Connect (OSTI)

    Fasiello, Matteo; Tolley, Andrew J. E-mail: andrew.j.tolley@case.edu

    2013-12-01

    We give a simple derivation of a cosmological bound on the graviton mass for spatially flat FRW solutions in massive gravity with an FRW reference metric and for bigravity theories. This bound comes from the requirement that the kinetic term of the helicity zero mode of the graviton is positive definite. The bound is dependent only on the parameters in the massive gravity potential and the Hubble expansion rate for the two metrics. We derive the decoupling limit of bigravity and FRW massive gravity, and use this to give an independent derivation of the cosmological bound. We recover our previous results that the tension between satisfying the Friedmann equation and the cosmological bound is sufficient to rule out all observationally relevant FRW solutions for massive gravity with an FRW reference metric. In contrast, in bigravity this tension is resolved due to different nature of the Vainshtein mechanism. We find that in bigravity theories there exists an FRW solution with late-time self-acceleration for which the kinetic terms for the helicity-2, helicity-1 and helicity-0 are generically nonzero and positive making this a compelling candidate for a model of cosmic acceleration. We confirm that the generalized bound is saturated for the candidate partially massless (bi)gravity theories but the existence of helicity-1/helicity-0 interactions implies the absence of the conjectured partially massless symmetry for both massive gravity and bigravity.

  14. The $Z$-invariant massive Laplacian on isoradial graphs

    E-Print Network [OSTI]

    Cédric Boutillier; Béatrice de Tilière; Kilian Raschel

    2015-04-03

    We introduce a one-parameter family of massive Laplacian operators $(\\Delta^{m(k)})_{k\\in[0,1)}$ defined on isoradial graphs, involving elliptic functions. We prove an explicit formula for minus the inverse of $\\Delta^{m(k)}$, the massive Green function, which has the remarkable property of only depending on the local geometry of the graph, and compute its asymptotics. We study the corresponding statistical mechanics model of random rooted spanning forests. We prove an explicit local formula for an infinite volume Boltzmann measure, and for the free energy of the model. We show that the model undergoes a second order phase transition at $k=0$, thus proving that spanning trees corresponding to the Laplacian introduced by Kenyon are critical. We prove that the massive Laplacian operators $(\\Delta^{m(k)})_{k\\in(0,1)}$ provide a one-parameter family of $Z$-invariant rooted spanning forest models. When the isoradial graph is moreover $\\mathbb{Z}^2$-periodic, we consider the spectral curve $\\mathcal{C}^k$ of the characteristic polynomial of the massive Laplacian. We provide an explicit parametrization of the curve and prove that it is Harnack and has genus 1. We further show that every Harnack curve of genus 1 with $(z,w)\\leftrightarrow(z^{-1},w^{-1})$ symmetry arises from such a massive Laplacian.

  15. Spontaneous Lorentz and diffeomorphism violation, massive modes, and gravity

    SciTech Connect (OSTI)

    Bluhm, Robert; Fung Shuhong; Kostelecky, V. Alan

    2008-03-15

    Theories with spontaneous local Lorentz and diffeomorphism violation contain massless Nambu-Goldstone modes, which arise as field excitations in the minimum of the symmetry-breaking potential. If the shape of the potential also allows excitations above the minimum, then an alternative gravitational Higgs mechanism can occur in which massive modes involving the metric appear. The origin and basic properties of the massive modes are addressed in the general context involving an arbitrary tensor vacuum value. Special attention is given to the case of bumblebee models, which are gravitationally coupled vector theories with spontaneous local Lorentz and diffeomorphism violation. Mode expansions are presented in both local and spacetime frames, revealing the Nambu-Goldstone and massive modes via decomposition of the metric and bumblebee fields, and the associated symmetry properties and gauge fixing are discussed. The class of bumblebee models with kinetic terms of the Maxwell form is used as a focus for more detailed study. The nature of the associated conservation laws and the interpretation as a candidate alternative to Einstein-Maxwell theory are investigated. Explicit examples involving smooth and Lagrange-multiplier potentials are studied to illustrate features of the massive modes, including their origin, nature, dispersion laws, and effects on gravitational interactions. In the weak static limit, the massive mode and Lagrange-multiplier fields are found to modify the Newton and Coulomb potentials. The nature and implications of these modifications are examined.

  16. Kalman Filter Tracking on Parallel Architectures

    E-Print Network [OSTI]

    Giuseppe Cerati; Peter Elmer; Steven Lantz; Kevin McDermott; Dan Riley; Matevž Tadel; Peter Wittich; Frank Würthwein; Avi Yagil

    2015-05-18

    Power density constraints are limiting the performance improvements of modern CPUs. To address this we have seen the introduction of lower-power, multi-core processors, but the future will be even more exciting. In order to stay within the power density limits but still obtain Moore's Law performance/price gains, it will be necessary to parallelize algorithms to exploit larger numbers of lightweight cores and specialized functions like large vector units. Example technologies today include Intel's Xeon Phi and GPGPUs. Track finding and fitting is one of the most computationally challenging problems for event reconstruction in particle physics. At the High Luminosity LHC, for example, this will be by far the dominant problem. The need for greater parallelism has driven investigations of very different track finding techniques including Cellular Automata or returning to Hough Transform. The most common track finding techniques in use today are however those based on the Kalman Filter. Significant experience has been accumulated with these techniques on real tracking detector systems, both in the trigger and offline. They are known to provide high physics performance, are robust and are exactly those being used today for the design of the tracking system for HL-LHC. Our previous investigations showed that, using optimized data structures, track fitting with Kalman Filter can achieve large speedup both with Intel Xeon and Xeon Phi. We report here our further progress towards an end-to-end track reconstruction algorithm fully exploiting vectorization and parallelization techniques in a realistic simulation setup.

  17. Xyce parallel electronic simulator : reference guide.

    SciTech Connect (OSTI)

    Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Warrender, Christina E.; Keiter, Eric Richard; Pawlowski, Roger Patrick

    2011-05-01

    This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users Guide. The Xyce Parallel Electronic Simulator has been written to support, in a rigorous manner, the simulation needs of the Sandia National Laboratories electrical designers. It is targeted specifically to run on large-scale parallel computing platforms but also runs well on a variety of architectures including single processor workstations. It also aims to support a variety of devices and models specific to Sandia needs. This document is intended to complement the Xyce Users Guide. It contains comprehensive, detailed information about a number of topics pertinent to the usage of Xyce. Included in this document is a netlist reference for the input-file commands and elements supported within Xyce; a command line reference, which describes the available command line arguments for Xyce; and quick-references for users of other circuit codes, such as Orcad's PSpice and Sandia's ChileSPICE.

  18. Magnetic Braiding and Parallel Electric Fields

    E-Print Network [OSTI]

    A. L. Wilmot-Smith; G. Hornig; D. I. Pontin

    2008-10-08

    The braiding of the solar coronal magnetic field via photospheric motions - with subsequent relaxation and magnetic reconnection -- is one of the most widely debated ideas of solar physics. We readdress the theory in the light of developments in three-dimensional magnetic reconnection theory. It is known that the integrated parallel electric field along field lines is the key quantity determining the rate of reconnection, in contrast with the two-dimensional case where the electric field itself is the important quantity. We demonstrate that this difference becomes crucial for sufficiently complex magnetic field structures. A numerical method is used to relax a braided magnetic field to an ideal force-free equilibrium; that equilibrium is found to be smooth, with only large- scale current structures. However, the equilibrium is shown to have a highly filamentary integrated parallel current structure with extremely short length- scales. An analytical model is developed to show that, in a coronal situation, the length scales associated with the integrated parallel current structures will rapidly decrease with increasing complexity, or degree of braiding, of the magnetic field. Analysis shows the decrease in these length scales will, for any finite resistivity, eventually become inconsistent with the stability of a force- free field. Thus the inevitable consequence of the magnetic braiding process is shown to be a loss of equilibrium of the coronal field, probably via magnetic reconnection events.

  19. Earthquake Ground Motion Modeling on Parallel Computers Hesheng Bao

    E-Print Network [OSTI]

    California at Berkeley, University of

    generator, as well as parallel numerical methods for applying seismic forces, incorporating absorbing generation, parallel unstructured PDE solvers, parallelizing compilers, seismic wave propagation, strong as necessary. Assessing the free­field ground motion to which a structure will be exposed during its lifetime

  20. An XYZ Parallel-Kinematic Flexure Mechanism With Geometrically

    E-Print Network [OSTI]

    Awtar, Shorya

    An XYZ Parallel-Kinematic Flexure Mechanism With Geometrically Decoupled Degrees of Freedom Shorya of Michigan, Ann Arbor, MI 48109 A novel parallel-kinematic flexure mechanism that provides highly decoupled parallel-kinematic flexure mechanism. The proposed concept is inherently free of geometric overconstraints

  1. Exploiting Visualization and Direct Manipulation to Make Parallel Tools More

    E-Print Network [OSTI]

    Pancake, Cherri M.

    Exploiting Visualization and Direct Manipulation to Make Parallel Tools More Communicative Cherri M@cs.orst.edu http://www.cs.orst.edu/ pancake Abstract. Parallel tools rely on graphical techniques to improve be exploited in parallel tools, in order to improve the naturalness with which the user interacts

  2. IBM Parallel Environment for AIX 5L Introduction

    E-Print Network [OSTI]

    Hickman, Mark

    IBM Parallel Environment for AIX 5L Introduction Version 4 Release 2, Modification 2 SA22-7947-04 #12;#12;IBM Parallel Environment for AIX 5L Introduction Version 4 Release 2, Modification 2 SA22 of IBM Parallel Environment for AIX 5L (product number 5765-F83) and to all subsequent releases

  3. IBM Parallel Environment for AIX 5L MPI Programming Guide

    E-Print Network [OSTI]

    Hickman, Mark

    IBM Parallel Environment for AIX 5L MPI Programming Guide Version 4 Release 2, Modification 2 SA22-7945-04 #12;#12;IBM Parallel Environment for AIX 5L MPI Programming Guide Version 4 Release 2, Modification 2, Modification 2 of IBM Parallel Environment for AIX 5L (product number 5765-F83) and to all subsequent releases

  4. IBM Parallel Environment for Linux MPI Programming Guide

    E-Print Network [OSTI]

    Hickman, Mark

    IBM Parallel Environment for Linux MPI Programming Guide Version 4 Release 2 SA23-2219-00 #12;#12;IBM Parallel Environment for Linux MPI Programming Guide Version 4 Release 2 SA23-2219-00 #12;Note. First Edition (April 2006) This edition applies to version 4, release 2, modification 0 of IBM Parallel

  5. OS and Runtime Support for Efficiently Managing Cores in Parallel Applications

    E-Print Network [OSTI]

    Klues, Kevin Alan

    2015-01-01

    Composing parallel software efficiently with lithe. ” In:Runtime Support for Efficiently Managing Cores in ParallelRuntime Support for Efficiently Managing Cores in Parallel

  6. Hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    E-Print Network [OSTI]

    Howison, Mark

    2010-01-01

    W. , and Childs, H. (2010) MPI-hybrid parallelism for volumeHybrid Parallelism for Volume Rendering on Large, Multi-corecharacteristics of “hybrid” parallel program- ming and

  7. Hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    E-Print Network [OSTI]

    Howison, Mark

    2010-01-01

    Hybrid Parallelism for Volume Rendering on Large, Multi-corendings indicate that the hybrid-parallel implementation, atpassing against a “hybrid” parallel im- plementation, which

  8. Massive "spin-2" theories in arbitrary $D \\ge 3$ dimensions

    E-Print Network [OSTI]

    D. Dalmazi; A. L. R. dos Santos; E. L. Mendonça

    2014-08-28

    Here we show that in arbitrary dimensions $D\\ge 3$ there are two families of second order Lagrangians describing massive "spin-2" particles via a nonsymmetric rank-2 tensor. They differ from the usual Fierz-Pauli theory in general. At zero mass one of the families is Weyl invariant. Such massless theory has no particle content in $D=3$ and gives rise, via master action, to a dual higher order (in derivatives) description of massive spin-2 particles in $D=3$ where both the second and the fourth order terms are Weyl invariant, contrary to the linearized New Massive Gravity. However, only the fourth order term is invariant under arbitrary antisymmetric shifts. Consequently, the antisymmetric part of the tensor $e_{[\\mu\

  9. Translation invariant time-dependent solutions to massive gravity

    SciTech Connect (OSTI)

    Mourad, J.; Steer, D.A. E-mail: steer@apc.univ-paris7.fr

    2013-12-01

    Homogeneous time-dependent solutions of massive gravity generalise the plane wave solutions of the linearised Fierz-Pauli equations for a massive spin-two particle, as well as the Kasner solutions of General Relativity. We show that they also allow a clear counting of the degrees of freedom and represent a simplified framework to work out the constraints, the equations of motion and the initial value formulation. We work in the vielbein formulation of massive gravity, find the phase space resulting from the constraints and show that several disconnected sectors of solutions exist some of which are unstable. The initial values determine the sector to which a solution belongs. Classically, the theory is not pathological but quantum mechanically the theory may suffer from instabilities. The latter are not due to an extra ghost-like degree of freedom.

  10. Massive gravitational waves in Chern-Simons modified gravity

    SciTech Connect (OSTI)

    Myung, Yun Soo; Moon, Taeyoon E-mail: tymoon@inje.ac.kr

    2014-10-01

    We consider the nondynamical Chern-Simons (nCS) modified gravity, which is regarded as a parity-odd theory of massive gravity in four dimensions. We first find polarization modes of gravitational waves for ?=x/? in nCS modified gravity by using the Newman-Penrose formalism where the null complex tetrad is necessary to specify gravitational waves. We show that in the Newman–Penrose formalism, the number of polarization modes is one in addition to an unspecified ?{sub 4}, implying three degrees of freedom for ?=x/?. This compares with two for a canonical embedding of ?=t/?. Also, if one introduces the Ricci tensor formalism to describe a massive graviton arising from the nCS modified gravity, one finds one massive mode after making second-order wave equations, which is compared to five found from the parity-even Einstein–Weyl gravity.

  11. Parallel Implementation of the PHOENIX Generalized Stellar Atmosphere Program. III: A parallel algorithm for direct opacity sampling

    E-Print Network [OSTI]

    Peter H. Hauschildt; David K. Lowenthal; E. Baron

    2001-04-16

    We describe two parallel algorithms for line opacity calculations based on a local file and on a global file approach. The performance and scalability of both approaches is discussed for different test cases and very different parallel computing systems. The results show that a global file approach is more efficient on high-performance parallel supercomputers with dedicated parallel I/O subsystem whereas the local file approach is very useful on farms of workstations, e.g., cheap PC clusters.

  12. The Parallel and Distributed Algorithms This chapter contains a brief review of both parallel and distributed computing,

    E-Print Network [OSTI]

    Goddard III, William A.

    146 Chapter VI The Parallel and Distributed Algorithms #12; 147 Abstract This chapter contains of concurrent computing. Based on the resonance method and program design described in Chapter V, an algorithm algorithm lends itself to effective parallelization. The main requirement for effective parallelization

  13. Parallel Dimers and Anti-parallel Tetramers Formed by Epidermal Growth Factor Receptor Pathway Substrate Clone 15 (EPS15)*

    E-Print Network [OSTI]

    Kirchhausen, Tomas

    Parallel Dimers and Anti-parallel Tetramers Formed by Epidermal Growth Factor Receptor Pathway- dependent endocytic traffic. We report here that Eps15 forms dimers and tetramers of distinct shape. The Eps tetramer has a "dumbbell" shape, 31 nm in length; it is formed by the anti-parallel association of two Eps

  14. Energy momentum flows for the massive vector field

    E-Print Network [OSTI]

    George Horton; Chris Dewdney

    2006-09-26

    We present a causal trajectory interpretation for the massive vector field, based on the flows of rest energy and a conserved density defined using the time-like eigenvectors and eigenvalues of the stress-energy-momentum tensor. This work extends our previous work which used a similar procedure for the scalar field. The massive, spin-one, complex vector field is discussed in detail and solutions are classified using the Pauli-Lubanski spin vector. The flows of energy-momentum are illustrated in a simple example of standing waves in a plane.

  15. Particle-Antiparticle Metamorphosis of Massive Majorana Neutrinos and Gauginos

    E-Print Network [OSTI]

    D. V. Ahluwalia-Khalilova

    2003-06-13

    Recent results on neutrinoless double beta decay, as reported by Klapdor-Kleingrothaus et al., take us for the first time into the realm of Majorana spacetime structure. However, this structure has either been treated as an afterthought to the Dirac construct; or, when it has been attended to in its own right, its physical and mathematical content was never fully unearthed. In this Letter,we undertake to remedy the existing situation. We present a detailed formalism required for the description of the non-trivial spacetime structure underlying the "nu-nubar" metamorphosis - where "nu" generically represents a massive Majorana neutrino, or a massive gaugino.

  16. A brief parallel I/O tutorial.

    SciTech Connect (OSTI)

    Ward, H. Lee

    2010-03-01

    This document provides common best practices for the efficient utilization of parallel file systems for analysts and application developers. A multi-program, parallel supercomputer is able to provide effective compute power by aggregating a host of lower-power processors using a network. The idea, in general, is that one either constructs the application to distribute parts to the different nodes and processors available and then collects the result (a parallel application), or one launches a large number of small jobs, each doing similar work on different subsets (a campaign). The I/O system on these machines is usually implemented as a tightly-coupled, parallel application itself. It is providing the concept of a 'file' to the host applications. The 'file' is an addressable store of bytes and that address space is global in nature. In essence, it is providing a global address space. Beyond the simple reality that the I/O system is normally composed of a small, less capable, collection of hardware, that concept of a global address space will cause problems if not very carefully utilized. How much of a problem and the ways in which those problems manifest will be different, but that it is problem prone has been well established. Worse, the file system is a shared resource on the machine - a system service. What an application does when it uses the file system impacts all users. It is not the case that some portion of the available resource is reserved. Instead, the I/O system responds to requests by scheduling and queuing based on instantaneous demand. Using the system well contributes to the overall throughput on the machine. From a solely self-centered perspective, using it well reduces the time that the application or campaign is subject to impact by others. The developer's goal should be to accomplish I/O in a way that minimizes interaction with the I/O system, maximizes the amount of data moved per call, and provides the I/O system the most information about the I/O transfer per request.

  17. Carbothermic reduction with parallel heat sources

    DOE Patents [OSTI]

    Troup, Robert L. (Murrysville, PA); Stevenson, David T. (Washington Township, Washington County, PA)

    1984-12-04

    Disclosed are apparatus and method of carbothermic direct reduction for producing an aluminum alloy from a raw material mix including aluminum oxide, silicon oxide, and carbon wherein parallel heat sources are provided by a combustion heat source and by an electrical heat source at essentially the same position in the reactor, e.g., such as at the same horizontal level in the path of a gravity-fed moving bed in a vertical reactor. The present invention includes providing at least 79% of the heat energy required in the process by the electrical heat source.

  18. Parallel State Estimation Assessment with Practical Data

    SciTech Connect (OSTI)

    Chen, Yousu; Jin, Shuangshuang; Rice, Mark J.; Huang, Zhenyu

    2014-10-31

    This paper presents a full-cycle parallel state estimation (PSE) implementation using a preconditioned conjugate gradient algorithm. The developed code is able to solve large-size power system state estimation within 5 seconds using real-world data, comparable to the Supervisory Control And Data Acquisition (SCADA) rate. This achievement allows the operators to know the system status much faster to help improve grid reliability. Case study results of the Bonneville Power Administration (BPA) system with real measurements are presented. The benefits of fast state estimation are also discussed.

  19. Parallel heater system for subsurface formations

    DOE Patents [OSTI]

    Harris, Christopher Kelvin (Houston, TX); Karanikas, John Michael (Houston, TX); Nguyen, Scott Vinh (Houston, TX)

    2011-10-25

    A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

  20. Parallel Programming and Optimization for Intel Architecture

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| Department ofStephen PSeptember|March Study Could LeadParallel

  1. Deep mutational scanning: assessing protein function on a massive scale

    E-Print Network [OSTI]

    Fields, Stan

    Deep mutational scanning: assessing protein function on a massive scale Carlos L. Araya1 of mutants that span the activity range from high to low. Such deep mutational scanning approaches are rapid and inexpensive, with the potential for broad utility. Here, we discuss the emergence of deep mutational scanning

  2. Massive global ozone loss predicted following regional nuclear conflict

    E-Print Network [OSTI]

    Robock, Alan

    that nuclear war could be winnable, and preceded the first significant reductions in nuclear weapons stockpiles, the proliferation of nuclear weapons has produced greater risks of a regional nuclear conflict. At the same timeMassive global ozone loss predicted following regional nuclear conflict Michael J. Mills* , Owen B

  3. First HARPSpol discoveries of magnetic fields in massive stars

    E-Print Network [OSTI]

    Alecian, E; Neiner, C; Wade, G A; de Batz, B; Henrichs, H; Grunhut, J H; Bouret, J -C; Briquet, M; Gagne, M; Naze, Y; Oksala, M E; Rivinius, T; Townsend, R H D; Walborn, N R; Weiss, W

    2011-01-01

    In the framework of the Magnetism in Massive Stars (MiMeS) project, a HARPSpol Large Program at the 3.6m-ESO telescope has recently started to collect high-resolution spectropolarimetric data of a large number of Southern massive OB stars in the field of the Galaxy and in many young clusters and associations. In this Letter, we report on the first discoveries of magnetic fields in two massive stars with HARPSpol - HD 130807 and HD 122451, and confirm the presence of a magnetic field at the surface of HD 105382 that was previously observed with a low spectral resolution device. The longitudinal magnetic field measurements are strongly varying for HD 130807 from $\\sim$-100 G to $\\sim$700 G. Those of HD 122451 and HD 105382 are less variable with values ranging from $\\sim$-40 to -80 G, and from $\\sim$-300 to -600 G, respectively. The discovery and confirmation of three new magnetic massive stars, including at least two He-weak stars, is an important contribution to one of the MiMeS objectives: the understanding ...

  4. Mitigation of Sounding Pilot Contamination in Massive MIMO Systems

    E-Print Network [OSTI]

    Bahk, Saewoong

    Mitigation of Sounding Pilot Contamination in Massive MIMO Systems Taeseop Lee, Hyung-Sin Kim contamination of cell edge users or a lowered number of serviced users in a multi-cell scenario. In this paper the quality of service (QoS) of mobile users by mitigating the pilot contamination as well as minimize

  5. Constraints on massive gravity theory from big bang nucleosynthesis

    E-Print Network [OSTI]

    G. Lambiase

    2012-08-27

    The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The cosmological consequences of the model are also discussed in the framework of the PAMELA experiment.

  6. Free energy of topologically massive gravity and flat space holography

    E-Print Network [OSTI]

    Grumiller, Daniel

    2015-01-01

    We calculate the free energy from the on-shell action for topologically massive gravity with negative and vanishing cosmological constant, thereby providing a first principles derivation of the free energy of BTZ black holes and flat space cosmologies. We summarize related recent checks of flat space holography.

  7. Free energy of topologically massive gravity and flat space holography

    E-Print Network [OSTI]

    Daniel Grumiller; Wout Merbis

    2015-09-28

    We calculate the free energy from the on-shell action for topologically massive gravity with negative and vanishing cosmological constant, thereby providing a first principles derivation of the free energy of BTZ black holes and flat space cosmologies. We summarize related recent checks of flat space holography.

  8. Switch for serial or parallel communication networks

    DOE Patents [OSTI]

    Crosette, D.B.

    1994-07-19

    A communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network linking a multi-processor or parallel processing system has a very low software processing overhead in order to accommodate random burst of high density data. Associated with each processor is a communication switch. A data source and a data destination, a sensor suite or robot for example, may also be associated with a switch. The configuration of the switches in the network are coordinated through a master processor node and depends on the operational phase of the multi-processor network: data acquisition, data processing, and data exchange. The master processor node passes information on the state to be assumed by each switch to the processor node associated with the switch. The processor node then operates a series of multi-state switches internal to each communication switch. The communication switch does not parse and interpret communication protocol and message routing information. During a data acquisition phase, the communication switch couples sensors producing data to the processor node associated with the switch, to a downlink destination on the communications network, or to both. It also may couple an uplink data source to its processor node. During the data exchange phase, the switch couples its processor node or an uplink data source to a downlink destination (which may include a processor node or a robot), or couples an uplink source to its processor node and its processor node to a downlink destination. 9 figs.

  9. Switch for serial or parallel communication networks

    DOE Patents [OSTI]

    Crosette, Dario B. (DeSoto, TX)

    1994-01-01

    A communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network linking a multi-processor or parallel processing system has a very low software processing overhead in order to accommodate random burst of high density data. Associated with each processor is a communication switch. A data source and a data destination, a sensor suite or robot for example, may also be associated with a switch. The configuration of the switches in the network are coordinated through a master processor node and depends on the operational phase of the multi-processor network: data acquisition, data processing, and data exchange. The master processor node passes information on the state to be assumed by each switch to the processor node associated with the switch. The processor node then operates a series of multi-state switches internal to each communication switch. The communication switch does not parse and interpret communication protocol and message routing information. During a data acquisition phase, the communication switch couples sensors producing data to the processor node associated with the switch, to a downlink destination on the communications network, or to both. It also may couple an uplink data source to its processor node. During the data exchange phase, the switch couples its processor node or an uplink data source to a downlink destination (which may include a processor node or a robot), or couples an uplink source to its processor node and its processor node to a downlink destination.

  10. Efficient Algorithms for Parallel Excitation and Parallel Imaging with Large Arrays 

    E-Print Network [OSTI]

    Feng, Shuo

    2013-08-12

    in reconstructions. 2.3 Parallel Excitation The field strength of the current clinical scanners are advancing to 3 Tesla or even 7 Tesla which can tremendously improve the imaging quality. However, many high field related problems remain unsolved, for example...

  11. reiner@hartenstein.de R. Hartenstein: Massively Reducing Electricity Consumption and Greenhouse

    E-Print Network [OSTI]

    Hartenstein, Reiner

    reiner@hartenstein.de R. Hartenstein: Massively Reducing Electricity Consumption and Greenhouse Electricity Consumption and Greenhouse Gases by Innovative Computing Education Reiner Hartenstein CCC 2009 complete #12;reiner@hartenstein.de R. Hartenstein: Massively Reducing Electricity Consumption

  12. Mass dependence of the vacuum energy density in the massive Schwinger model

    E-Print Network [OSTI]

    Taekoon Lee

    2007-03-09

    The vacuum energy density of the massive Schwinger model is shown to be not power expandable in the fermion mass.

  13. Sub-Second Parallel State Estimation

    SciTech Connect (OSTI)

    Chen, Yousu; Rice, Mark J.; Glaesemann, Kurt R.; Wang, Shaobu; Huang, Zhenyu

    2014-10-31

    This report describes the performance of Pacific Northwest National Laboratory (PNNL) sub-second parallel state estimation (PSE) tool using the utility data from the Bonneville Power Administrative (BPA) and discusses the benefits of the fast computational speed for power system applications. The test data were provided by BPA. They are two-days’ worth of hourly snapshots that include power system data and measurement sets in a commercial tool format. These data are extracted out from the commercial tool box and fed into the PSE tool. With the help of advanced solvers, the PSE tool is able to solve each BPA hourly state estimation problem within one second, which is more than 10 times faster than today’s commercial tool. This improved computational performance can help increase the reliability value of state estimation in many aspects: (1) the shorter the time required for execution of state estimation, the more time remains for operators to take appropriate actions, and/or to apply automatic or manual corrective control actions. This increases the chances of arresting or mitigating the impact of cascading failures; (2) the SE can be executed multiple times within time allowance. Therefore, the robustness of SE can be enhanced by repeating the execution of the SE with adaptive adjustments, including removing bad data and/or adjusting different initial conditions to compute a better estimate within the same time as a traditional state estimator’s single estimate. There are other benefits with the sub-second SE, such as that the PSE results can potentially be used in local and/or wide-area automatic corrective control actions that are currently dependent on raw measurements to minimize the impact of bad measurements, and provides opportunities to enhance the power grid reliability and efficiency. PSE also can enable other advanced tools that rely on SE outputs and could be used to further improve operators’ actions and automated controls to mitigate effects of severe events on the grid. The power grid continues to grow and the number of measurements is increasing at an accelerated rate due to the variety of smart grid devices being introduced. A parallel state estimation implementation will have better performance than traditional, sequential state estimation by utilizing the power of high performance computing (HPC). This increased performance positions parallel state estimators as valuable tools for operating the increasingly more complex power grid.

  14. Cloud Futures Workshop 2010 Cloud Computing Support for Massively Social Gaming Alexandru Iosup

    E-Print Network [OSTI]

    Iosup, Alexandru

    1 Cloud Futures Workshop 2010 ­ Cloud Computing Support for Massively Social Gaming Alexandru Iosup Pierre (Vrije U.). Cloud Computing Support for Massively Social Gaming (Rain for the Thirsty) #12;Cloud Futures Workshop 2010 ­ Cloud Computing Support for Massively Social Gaming 2 Intermezzo: Tips on how

  15. Broadcasting a message in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Faraj, Daniel A

    2014-11-18

    Methods, systems, and products are disclosed for broadcasting a message in a parallel computer that includes: transmitting, by the logical root to all of the nodes directly connected to the logical root, a message; and for each node except the logical root: receiving the message; if that node is the physical root, then transmitting the message to all of the child nodes except the child node from which the message was received; if that node received the message from a parent node and if that node is not a leaf node, then transmitting the message to all of the child nodes; and if that node received the message from a child node and if that node is not the physical root, then transmitting the message to all of the child nodes except the child node from which the message was received and transmitting the message to the parent node.

  16. Internode data communications in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Miller, Douglas R; Parker, Jeffrey J; Ratterman, Joseph D; Smith, Brian E

    2014-02-11

    Internode data communications in a parallel computer that includes compute nodes that each include main memory and a messaging unit, the messaging unit including computer memory and coupling compute nodes for data communications, in which, for each compute node at compute node boot time: a messaging unit allocates, in the messaging unit's computer memory, a predefined number of message buffers, each message buffer associated with a process to be initialized on the compute node; receives, prior to initialization of a particular process on the compute node, a data communications message intended for the particular process; and stores the data communications message in the message buffer associated with the particular process. Upon initialization of the particular process, the process establishes a messaging buffer in main memory of the compute node and copies the data communications message from the message buffer of the messaging unit into the message buffer of main memory.

  17. Optimized data communications in a parallel computer

    DOE Patents [OSTI]

    Faraj, Daniel A.

    2014-08-19

    A parallel computer includes nodes that include a network adapter that couples the node in a point-to-point network and supports communications in opposite directions of each dimension. Optimized communications include: receiving, by a network adapter of a receiving compute node, a packet--from a source direction--that specifies a destination node and deposit hints. Each hint is associated with a direction within which the packet is to be deposited. If a hint indicates the packet to be deposited in the opposite direction: the adapter delivers the packet to an application on the receiving node; forwards the packet to a next node in the opposite direction if the receiving node is not the destination; and forwards the packet to a node in a direction of a subsequent dimension if the hints indicate that the packet is to be deposited in the direction of the subsequent dimension.

  18. Optimized data communications in a parallel computer

    DOE Patents [OSTI]

    Faraj, Daniel A

    2014-10-21

    A parallel computer includes nodes that include a network adapter that couples the node in a point-to-point network and supports communications in opposite directions of each dimension. Optimized communications include: receiving, by a network adapter of a receiving compute node, a packet--from a source direction--that specifies a destination node and deposit hints. Each hint is associated with a direction within which the packet is to be deposited. If a hint indicates the packet to be deposited in the opposite direction: the adapter delivers the packet to an application on the receiving node; forwards the packet to a next node in the opposite direction if the receiving node is not the destination; and forwards the packet to a node in a direction of a subsequent dimension if the hints indicate that the packet is to be deposited in the direction of the subsequent dimension.

  19. Clock Agreement Among Parallel Supercomputer Nodes

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jones, Terry R.; Koenig, Gregory A.

    2014-04-30

    This dataset presents measurements that quantify the clock synchronization time-agreement characteristics among several high performance computers including the current world's most powerful machine for open science, the U.S. Department of Energy's Titan machine sited at Oak Ridge National Laboratory. These ultra-fast machines derive much of their computational capability from extreme node counts (over 18000 nodes in the case of the Titan machine). Time-agreement is commonly utilized by parallel programming applications and tools, distributed programming application and tools, and system software. Our time-agreement measurements detail the degree of time variance between nodes and how that variance changes over time. The dataset includes empirical measurements and the accompanying spreadsheets.

  20. Link failure detection in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J. (Rochester, MN); Blocksome, Michael A. (Rochester, MN); Megerian, Mark G. (Rochester, MN); Smith, Brian E. (Rochester, MN)

    2010-11-09

    Methods, apparatus, and products are disclosed for link failure detection in a parallel computer including compute nodes connected in a rectangular mesh network, each pair of adjacent compute nodes in the rectangular mesh network connected together using a pair of links, that includes: assigning each compute node to either a first group or a second group such that adjacent compute nodes in the rectangular mesh network are assigned to different groups; sending, by each of the compute nodes assigned to the first group, a first test message to each adjacent compute node assigned to the second group; determining, by each of the compute nodes assigned to the second group, whether the first test message was received from each adjacent compute node assigned to the first group; and notifying a user, by each of the compute nodes assigned to the second group, whether the first test message was received.

  1. Intranode data communications in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Miller, Douglas R; Ratterman, Joseph D; Smith, Brian E

    2014-01-07

    Intranode data communications in a parallel computer that includes compute nodes configured to execute processes, where the data communications include: allocating, upon initialization of a first process of a computer node, a region of shared memory; establishing, by the first process, a predefined number of message buffers, each message buffer associated with a process to be initialized on the compute node; sending, to a second process on the same compute node, a data communications message without determining whether the second process has been initialized, including storing the data communications message in the message buffer of the second process; and upon initialization of the second process: retrieving, by the second process, a pointer to the second process's message buffer; and retrieving, by the second process from the second process's message buffer in dependence upon the pointer, the data communications message sent by the first process.

  2. Internode data communications in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J.; Blocksome, Michael A.; Miller, Douglas R.; Parker, Jeffrey J.; Ratterman, Joseph D.; Smith, Brian E.

    2013-09-03

    Internode data communications in a parallel computer that includes compute nodes that each include main memory and a messaging unit, the messaging unit including computer memory and coupling compute nodes for data communications, in which, for each compute node at compute node boot time: a messaging unit allocates, in the messaging unit's computer memory, a predefined number of message buffers, each message buffer associated with a process to be initialized on the compute node; receives, prior to initialization of a particular process on the compute node, a data communications message intended for the particular process; and stores the data communications message in the message buffer associated with the particular process. Upon initialization of the particular process, the process establishes a messaging buffer in main memory of the compute node and copies the data communications message from the message buffer of the messaging unit into the message buffer of main memory.

  3. Intranode data communications in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Miller, Douglas R; Ratterman, Joseph D; Smith, Brian E

    2013-07-23

    Intranode data communications in a parallel computer that includes compute nodes configured to execute processes, where the data communications include: allocating, upon initialization of a first process of a compute node, a region of shared memory; establishing, by the first process, a predefined number of message buffers, each message buffer associated with a process to be initialized on the compute node; sending, to a second process on the same compute node, a data communications message without determining whether the second process has been initialized, including storing the data communications message in the message buffer of the second process; and upon initialization of the second process: retrieving, by the second process, a pointer to the second process's message buffer; and retrieving, by the second process from the second process's message buffer in dependence upon the pointer, the data communications message sent by the first process.

  4. Parallel detecting, spectroscopic ellipsometers/polarimeters

    DOE Patents [OSTI]

    Furtak, Thomas E. (15927 W. Ellsworth, Golden, CO 80401)

    2002-01-01

    The parallel detecting spectroscopic ellipsometer/polarimeter sensor has no moving parts and operates in real-time for in-situ monitoring of the thin film surface properties of a sample within a processing chamber. It includes a multi-spectral source of radiation for producing a collimated beam of radiation directed towards the surface of the sample through a polarizer. The thus polarized collimated beam of radiation impacts and is reflected from the surface of the sample, thereby changing its polarization state due to the intrinsic material properties of the sample. The light reflected from the sample is separated into four separate polarized filtered beams, each having individual spectral intensities. Data about said four individual spectral intensities is collected within the processing chamber, and is transmitted into one or more spectrometers. The data of all four individual spectral intensities is then analyzed using transformation algorithms, in real-time.

  5. Clock Agreement Among Parallel Supercomputer Nodes

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jones, Terry R.; Koenig, Gregory A.

    This dataset presents measurements that quantify the clock synchronization time-agreement characteristics among several high performance computers including the current world's most powerful machine for open science, the U.S. Department of Energy's Titan machine sited at Oak Ridge National Laboratory. These ultra-fast machines derive much of their computational capability from extreme node counts (over 18000 nodes in the case of the Titan machine). Time-agreement is commonly utilized by parallel programming applications and tools, distributed programming application and tools, and system software. Our time-agreement measurements detail the degree of time variance between nodes and how that variance changes over time. The dataset includes empirical measurements and the accompanying spreadsheets.

  6. Broadcasting a message in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Faraj, Ahmad A

    2013-04-16

    Methods, systems, and products are disclosed for broadcasting a message in a parallel computer that includes: transmitting, by the logical root to all of the nodes directly connected to the logical root, a message; and for each node except the logical root: receiving the message; if that node is the physical root, then transmitting the message to all of the child nodes except the child node from which the message was received; if that node received the message from a parent node and if that node is not a leaf node, then transmitting the message to all of the child nodes; and if that node received the message from a child node and if that node is not the physical root, then transmitting the message to all of the child nodes except the child node from which the message was received and transmitting the message to the parent node.

  7. Evaluating and Utilizing Compute Capabilities of Parallel CPU...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in a single machine. It is therefore important to use benchmarks that can evaluate relative performance of these architectures in exploiting different types of parallelism....

  8. Parallel machine match-up scheduling with manufacturing cost considerations

    E-Print Network [OSTI]

    Aktürk, M. Selim; Atamtürk, Alper; Gürel, Sinan

    2010-01-01

    approach for the single machine scheduling problem. Journaldecisions on parallel CNC machines: -constraint approach.mechanism for the CNC machine scheduling problems with

  9. Mesoscale Simulations of Particulate Flows with Parallel Distributed...

    Office of Scientific and Technical Information (OSTI)

    Mesoscale Simulations of Particulate Flows with Parallel Distributed Lagrange Multiplier Technique Citation Details In-Document Search Title: Mesoscale Simulations of Particulate...

  10. Mesoscale simulations of particulate flows with parallel distributed...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Mesoscale simulations of particulate flows with parallel distributed Lagrange multiplier technique Citation Details In-Document Search Title: Mesoscale simulations...

  11. Compiling array computations for the Fresh Breeze Parallel Processor

    E-Print Network [OSTI]

    Ginzburg, Igor Arkadiy

    2007-01-01

    Fresh Breeze is a highly parallel architecture currently under development, which strives to provide high performance scientific computing with simple programmability. The architecture provides for multithreaded determinate ...

  12. A set of parallel, implicit methods for a reconstructed discontinuous...

    Office of Scientific and Technical Information (OSTI)

    methods for a reconstructed discontinuous Galerkin method for compressible flows on 3D hybrid grids Citation Details In-Document Search Title: A set of parallel, implicit methods...

  13. Parallel Large-Neighborhood Search Techniques for LNG Inventory ...

    E-Print Network [OSTI]

    Apr 17, 2014 ... Parallel Large-Neighborhood Search Techniques for LNG Inventory Routing. Badrinarayanan Velamur Asokan(badri.velamur.asokan ***at*** ...

  14. Hybrid MPI/OpenMP parallel support vector machine training

    E-Print Network [OSTI]

    Kristian Woodsend

    2009-01-12

    Jan 12, 2009 ... A parallel implementation of Support Vector Machine training has been developed, using a combination of MPI and OpenMP. Using an interior ...

  15. De Novo Ultrascale Atomistic Simulations On High-End Parallel...

    Office of Scientific and Technical Information (OSTI)

    model transitioning assisted by graph-based event tracking. A tunable hierarchical cellular decomposition parallelization framework then maps the O(N) EDC algorithms onto...

  16. Giant black hole ringings induced by massive gravity

    E-Print Network [OSTI]

    Yves Decanini; Antoine Folacci; Mohamed Ould El Hadj

    2014-01-01

    A distorted black hole radiates gravitational waves in order to settle down in one of the geometries permitted by the no-hair theorem. During that relaxation phase, a characteristic damped ringing is generated. It can be theoretically constructed from the black hole quasinormal frequencies (which govern its oscillating behavior and its decay) and from the associated excitation factors (which determine intrinsically its amplitude) by carefully taking into account the source of the distortion. Here, by considering the Schwarzschild black hole in the framework of massive gravity, we show that the excitation factors have an unexpected strong resonant behavior leading to giant ringings which are, moreover, slowly decaying. Such extraordinary black hole ringings could be observed by the next generations of gravitational wave detectors and allow us to test the various massive gravity theories or their absence could be used to impose strong constraints on the graviton mass.

  17. Translation invariant time-dependent solutions to massive gravity II

    SciTech Connect (OSTI)

    Mourad, J.; Steer, D.A. E-mail: steer@apc.univ-paris7.fr

    2014-06-01

    This paper is a sequel to JCAP 12 (2013) 004 and is also devoted to translation-invariant solutions of ghost-free massive gravity in its moving frame formulation. Here we consider a mass term which is linear in the vielbein (corresponding to a ?{sub 3} term in the 4D metric formulation) in addition to the cosmological constant. We determine explicitly the constraints, and from the initial value formulation show that the time-dependent solutions can have singularities at a finite time. Although the constraints give, as in the ?{sub 1} case, the correct number of degrees of freedom for a massive spin two field, we show that the lapse function can change sign at a finite time causing a singular time evolution. This is very different to the ?{sub 1} case where time evolution is always well defined. We conclude that the ?{sub 3} mass term can be pathological and should be treated with care.

  18. Magnetic field studies of massive main sequence stars

    E-Print Network [OSTI]

    Schoeller, M; Ilyin, I; Kharchenko, N V; Briquet, M; Langer, N; Oskinova, L M

    2011-01-01

    We report on the status of our spectropolarimetric observations of massive stars. During the last years, we have discovered magnetic fields in many objects of the upper main sequence, including Be stars, beta Cephei and Slowly Pulsating B stars, and a dozen O stars. Since the effects of those magnetic fields have been found to be substantial by recent models, we are looking into their impact on stellar rotation, pulsation, stellar winds, and chemical abundances. Accurate studies of the age, environment, and kinematic characteristics of the magnetic stars are also promising to give us new insight into the origin of the magnetic fields. Furthermore, longer time series of magnetic field measurements allow us to observe the temporal variability of the magnetic field and to deduce the stellar rotation period and the magnetic field geometry. Studies of the magnetic field in massive stars are indispensable to understand the conditions controlling the presence of those fields and their implications on the stellar phy...

  19. INTERNAL GRAVITY WAVES IN MASSIVE STARS: ANGULAR MOMENTUM TRANSPORT

    SciTech Connect (OSTI)

    Rogers, T. M. [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85719 (United States); Lin, D. N. C. [Astronomy and Astrophysics Department, University of California, Santa Cruz, CA 95064 (United States); McElwaine, J. N. [Swiss Federal Institute for Snow and Avalanche Research, 11 Fluelastrasse, Davos Dorf (Switzerland); Lau, H. H. B., E-mail: tami@lpl.arizona.edu, E-mail: lin@ucolick.org, E-mail: james.mcelwaine@slf.ch, E-mail: hblau@astro.uni-bonn.de [Argelander-Institut for Astronomie, Universit Bonn Auf dem Huegel 71, D-53121 Bonn (Germany)

    2013-07-20

    We present numerical simulations of internal gravity waves (IGW) in a star with a convective core and extended radiative envelope. We report on amplitudes, spectra, dissipation, and consequent angular momentum transport by such waves. We find that these waves are generated efficiently and transport angular momentum on short timescales over large distances. We show that, as in Earth's atmosphere, IGW drive equatorial flows which change magnitude and direction on short timescales. These results have profound consequences for the observational inferences of massive stars, as well as their long term angular momentum evolution. We suggest IGW angular momentum transport may explain many observational mysteries, such as: the misalignment of hot Jupiters around hot stars, the Be class of stars, Ni enrichment anomalies in massive stars, and the non-synchronous orbits of interacting binaries.

  20. Effects of axions on Nucleosynthesis in massive stars

    E-Print Network [OSTI]

    Aoyama, Shohei

    2015-01-01

    We investigate the effect of the axion cooling on the nucleosynthesis in a massive star with $16M_{\\odot}$ by standard stellar evolution calculation. We find that the axion cooling suppresses the nuclear reactions in carbon, oxygen and silicon burning phases because of the extraction of the energy. As a result, larger amounts of the already synthesized neon and magnesium remain without being consumed to produce further heavier elements. Even in the case with the axion-photon coupling constant $g_{a\\gamma}= 10^{-11}$ GeV$^{-1}$, which is six times smaller than the current upper limit, the amount of neon and magnesium that remain just before the core-collapse supernova explosion is considerably larger than the standard value. This implies that we could give a more stringent constraint on $g_{a\\gamma}$ from the nucleosynthesis of heavy elements in massive stars.

  1. The halo model in a massive neutrino cosmology

    E-Print Network [OSTI]

    Elena Massara; Francisco Villaescusa-Navarro; Matteo Viel

    2015-01-20

    We provide a quantitative analysis of the halo model in the context of massive neutrino cosmologies. We discuss all the ingredients necessary to model the non-linear matter and cold dark matter power spectra and compare with the results of N-body simulations that incorporate massive neutrinos. Our neutrino halo model is able to capture the non-linear behavior of matter clustering with a $\\sim 20\\%$ accuracy up to very non-linear scales of $k=10~h/$Mpc (which would be affected by baryon physics). The largest discrepancies arise in the range $k=0.5-1~h/$Mpc where the 1-halo and 2-halo terms are comparable and are present also in a massless neutrino cosmology. However, at scales $kOccupation Distribution scheme and our halo model extension.

  2. Galaxy bulges and their massive black holes: a review

    E-Print Network [OSTI]

    Alister W. Graham

    2015-02-17

    With references to both key and oft-forgotten pioneering works, this article starts by presenting a review into how we came to believe in the existence of massive black holes at the centres of galaxies. It then presents the historical development of the near-linear (black hole)-(host spheroid) mass relation, before explaining why this has recently been dramatically revised. Past disagreement over the slope of the (black hole)-(velocity dispersion) relation is also explained, and the discovery of sub-structure within the (black hole)-(velocity dispersion) diagram is discussed. As the search for the fundamental connection between massive black holes and their host galaxies continues, the competing array of additional black hole mass scaling relations for samples of predominantly inactive galaxies are presented.

  3. Exotic massive hadrons and ultra-high energy cosmic rays

    E-Print Network [OSTI]

    Ivone F. M. Albuquerque; Glennys R. Farrar; Edward W. Kolb

    1998-10-02

    We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that masses in excess of about 50 GeV are inconsistent with the highest energy event observed. We also estimate that with sufficient statistics a uhecron of mass as low as 10 GeV may be distinguished from a proton.

  4. Static, massive fields and vacuum polarization potential in Rindler space

    E-Print Network [OSTI]

    B. Linet

    1997-04-03

    In Rindler space, we determine in terms of special functions the expression of the static, massive scalar or vector field generated by a point source. We find also an explicit integral expression of the induced electrostatic potential resulting from the vacuum polarization due to an electric charge at rest in the Rindler coordinates. For a weak acceleration, we give then an approximate expression in the Fermi coordinates associated with the uniformly accelerated observer.

  5. The halo model in a massive neutrino cosmology

    SciTech Connect (OSTI)

    Massara, Elena; Villaescusa-Navarro, Francisco; Viel, Matteo E-mail: villaescusa@oats.inaf.it

    2014-12-01

    We provide a quantitative analysis of the halo model in the context of massive neutrino cosmologies. We discuss all the ingredients necessary to model the non-linear matter and cold dark matter power spectra and compare with the results of N-body simulations that incorporate massive neutrinos. Our neutrino halo model is able to capture the non-linear behavior of matter clustering with a ?20% accuracy up to very non-linear scales of k = 10 h/Mpc (which would be affected by baryon physics). The largest discrepancies arise in the range k = 0.5 – 1 h/Mpc where the 1-halo and 2-halo terms are comparable and are present also in a massless neutrino cosmology. However, at scales k < 0.2 h/Mpc our neutrino halo model agrees with the results of N-body simulations at the level of 8% for total neutrino masses of < 0.3 eV. We also model the neutrino non-linear density field as a sum of a linear and clustered component and predict the neutrino power spectrum and the cold dark matter-neutrino cross-power spectrum up to k = 1 h/Mpc with ?30% accuracy. For masses below 0.15 eV the neutrino halo model captures the neutrino induced suppression, casted in terms of matter power ratios between massive and massless scenarios, with a 2% agreement with the results of N-body/neutrino simulations. Finally, we provide a simple application of the halo model: the computation of the clustering of galaxies, in massless and massive neutrinos cosmologies, using a simple Halo Occupation Distribution scheme and our halo model extension.

  6. Heterotic p-branes from Massive Sigma Models

    E-Print Network [OSTI]

    N. D. Lambert

    1996-07-11

    We explicitly construct massive (0,4) supersymmetric ADHM sigma models which have heterotic p-brane solitons as their conformal fixed points. These yield the familiar gauge 5-brane and a new 1-brane solution which preserve 1/2 and 1/4 of the spacetime supersymmetry respectively. We also discuss an analogous construction for the type II NS-NS p-branes using (4,4) supersymmetric models.

  7. Constraints on massive gravity theory from big bang nucleosynthesis

    SciTech Connect (OSTI)

    Lambiase, G., E-mail: lambiase@sa.infn.it [Dipartimento di Fisica 'E. R.Caianiello', Università di Salerno, 84081 Baronissi (Italy)

    2012-10-01

    The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The cosmological consequences of the model are also analyzed in the framework of the PAMELA experiment, i.e. an excess of positron events, that the conventional cosmology and particle physics cannot explain.

  8. A symmetric approach to the massive nonlinear sigma model

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ferrari, Ruggero

    In the present paper we extend to the massive case the procedure of divergences subtraction, previously introduced for the massless nonlinear sigma model (D = 4). Perturbative expansion in the number of loops is successfully constructed. The resulting theory depends on the Spontaneous Symmetry Breaking parameter v, on the mass m and on the radiative correction parameter ?. Fermions are not considered in the present work. SU(2) ? SU(2) is the group used.

  9. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

    2014-09-16

    Eager send data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints that specify a client, a context, and a task, including receiving an eager send data communications instruction with transfer data disposed in a send buffer characterized by a read/write send buffer memory address in a read/write virtual address space of the origin endpoint; determining for the send buffer a read-only send buffer memory address in a read-only virtual address space, the read-only virtual address space shared by both the origin endpoint and the target endpoint, with all frames of physical memory mapped to pages of virtual memory in the read-only virtual address space; and communicating by the origin endpoint to the target endpoint an eager send message header that includes the read-only send buffer memory address.

  10. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Davis, Kristan D.; Faraj, Daniel A.

    2014-07-22

    Algorithm selection for data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including specifications of a client, a context, and a task, endpoints coupled for data communications through the PAMI, including associating in the PAMI data communications algorithms and ranges of message sizes so that each algorithm is associated with a separate range of message sizes; receiving in an origin endpoint of the PAMI a data communications instruction, the instruction specifying transmission of a data communications message from the origin endpoint to a target endpoint, the data communications message characterized by a message size; selecting, from among the associated algorithms and ranges, a data communications algorithm in dependence upon the message size; and transmitting, according to the selected data communications algorithm from the origin endpoint to the target endpoint, the data communications message.

  11. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

    2014-09-02

    Eager send data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints that specify a client, a context, and a task, including receiving an eager send data communications instruction with transfer data disposed in a send buffer characterized by a read/write send buffer memory address in a read/write virtual address space of the origin endpoint; determining for the send buffer a read-only send buffer memory address in a read-only virtual address space, the read-only virtual address space shared by both the origin endpoint and the target endpoint, with all frames of physical memory mapped to pages of virtual memory in the read-only virtual address space; and communicating by the origin endpoint to the target endpoint an eager send message header that includes the read-only send buffer memory address.

  12. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

    2014-11-18

    Data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, endpoints coupled for data communications through the PAMI and through data communications resources, including receiving in an origin endpoint of the PAMI a SEND instruction, the SEND instruction specifying a transmission of transfer data from the origin endpoint to a first target endpoint; transmitting from the origin endpoint to the first target endpoint a Request-To-Send (`RTS`) message advising the first target endpoint of the location and size of the transfer data; assigning by the first target endpoint to each of a plurality of target endpoints separate portions of the transfer data; and receiving by the plurality of target endpoints the transfer data.

  13. Data communications for a collective operation in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Faraj, Daniel A

    2013-07-16

    Algorithm selection for data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including specifications of a client, a context, and a task, endpoints coupled for data communications through the PAMI, including associating in the PAMI data communications algorithms and bit masks; receiving in an origin endpoint of the PAMI a collective instruction, the instruction specifying transmission of a data communications message from the origin endpoint to a target endpoint; constructing a bit mask for the received collective instruction; selecting, from among the associated algorithms and bit masks, a data communications algorithm in dependence upon the constructed bit mask; and executing the collective instruction, transmitting, according to the selected data communications algorithm from the origin endpoint to the target endpoint, the data communications message.

  14. Fencing direct memory access data transfers in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Blocksome, Michael A; Mamidala, Amith R

    2014-02-11

    Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to segments of shared random access memory through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and a segment of shared memory; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.

  15. Data communications in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Davis, Kristan D; Faraj, Daniel A

    2013-07-09

    Algorithm selection for data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including specifications of a client, a context, and a task, endpoints coupled for data communications through the PAMI, including associating in the PAMI data communications algorithms and ranges of message sizes so that each algorithm is associated with a separate range of message sizes; receiving in an origin endpoint of the PAMI a data communications instruction, the instruction specifying transmission of a data communications message from the origin endpoint to a target endpoint, the data communications message characterized by a message size; selecting, from among the associated algorithms and ranges, a data communications algorithm in dependence upon the message size; and transmitting, according to the selected data communications algorithm from the origin endpoint to the target endpoint, the data communications message.

  16. Fencing direct memory access data transfers in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Blocksome, Michael A.; Mamidala, Amith R.

    2013-09-03

    Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to segments of shared random access memory through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and a segment of shared memory; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.

  17. Stellar populations of massive elliptical galaxies in very rich clusters

    E-Print Network [OSTI]

    Carretero, C; Beckman, J E

    2006-01-01

    We present a detailed stellar population analysis of 27 massive elliptical galaxies within 4 very rich clusters at redshift z~0.2: A115, A655, A963 and A2111. Using the new, high-resolution stellar populations models developed in our group, we obtained accurate estimates of the mean luminosity-weighted ages and relative abundances of CN, Mg and Fe. We have found that [CN/H] and [Mg/H] are correlated with sigma while [Fe/H] and Log(age) are not. In addition, both abundance ratios [CN/Fe] and [Mg/Fe] increase with sigma. Furthermore, the [CN/H]-sigma and [CN/Fe]-sigma slopes are steeper for galaxies in very rich clusters than those in the less dense Virgo and Coma clusters. On the other hand, [Mg/H]-sigma and [Mg/Fe]-sigma slopes keep constant as functions of the environment. Our results are compatible with a scenario in which the stellar populations of massive elliptical galaxies, independently of their environment and mass, had formation timescales shorter than ~1 Gyr. This result implies that massive ellipti...

  18. Current parallel I/O limitations to scalable data analysis.

    SciTech Connect (OSTI)

    Mascarenhas, Ajith Arthur; Pebay, Philippe Pierre

    2011-07-01

    This report describes the limitations to parallel scalability which we have encountered when applying our otherwise optimally scalable parallel statistical analysis tool kit to large data sets distributed across the parallel file system of the current premier DOE computational facility. This report describes our study to evaluate the effect of parallel I/O on the overall scalability of a parallel data analysis pipeline using our scalable parallel statistics tool kit [PTBM11]. In this goal, we tested it using the Jaguar-pf DOE/ORNL peta-scale platform on a large combustion simulation data under a variety of process counts and domain decompositions scenarios. In this report we have recalled the foundations of the parallel statistical analysis tool kit which we have designed and implemented, with the specific double intent of reproducing typical data analysis workflows, and achieving optimal design for scalable parallel implementations. We have briefly reviewed those earlier results and publications which allow us to conclude that we have achieved both goals. However, in this report we have further established that, when used in conjuction with a state-of-the-art parallel I/O system, as can be found on the premier DOE peta-scale platform, the scaling properties of the overall analysis pipeline comprising parallel data access routines degrade rapidly. This finding is problematic and must be addressed if peta-scale data analysis is to be made scalable, or even possible. In order to attempt to address these parallel I/O limitations, we will investigate the use the Adaptable IO System (ADIOS) [LZL+10] to improve I/O performance, while maintaining flexibility for a variety of IO options, such MPI IO, POSIX IO. This system is developed at ORNL and other collaborating institutions, and is being tested extensively on Jaguar-pf. Simulation code being developed on these systems will also use ADIOS to output the data thereby making it easier for other systems, such as ours, to process that data.

  19. Eighth SIAM conference on parallel processing for scientific computing: Final program and abstracts

    SciTech Connect (OSTI)

    NONE

    1997-12-31

    This SIAM conference is the premier forum for developments in parallel numerical algorithms, a field that has seen very lively and fruitful developments over the past decade, and whose health is still robust. Themes for this conference were: combinatorial optimization; data-parallel languages; large-scale parallel applications; message-passing; molecular modeling; parallel I/O; parallel libraries; parallel software tools; parallel compilers; particle simulations; problem-solving environments; and sparse matrix computations.

  20. Endpoint-based parallel data processing with non-blocking collective instructions in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Cernohous, Bob R; Ratterman, Joseph D; Smith, Brian E

    2014-11-18

    Methods, apparatuses, and computer program products for endpoint-based parallel data processing with non-blocking collective instructions in a parallel active messaging interface (`PAMI`) of a parallel computer are provided. Embodiments include establishing by a parallel application a data communications geometry, the geometry specifying a set of endpoints that are used in collective operations of the PAMI, including associating with the geometry a list of collective algorithms valid for use with the endpoints of the geometry. Embodiments also include registering in each endpoint in the geometry a dispatch callback function for a collective operation and executing without blocking, through a single one of the endpoints in the geometry, an instruction for the collective operation.

  1. Computing Nash Equilibria for Scheduling on Restricted Parallel Links

    E-Print Network [OSTI]

    Mavronicolas, Marios

    Computing Nash Equilibria for Scheduling on Restricted Parallel Links Martin Gairing Thomas L of assigning n jobs to m parallel machines. In a pure Nash equilibrium, no user may im- prove its own main result, we introduce a polynomial time algorithm to compute from any given assignment a pure Nash

  2. Parallelization of DQMC Simulation for Strongly Correlated Electron Systems

    E-Print Network [OSTI]

    California at Davis, University of

    with novelty by presenting a hybrid granularity parallelization (HGP) scheme that combines algo- rithmic, the HGP scheme explores the parallelism on different levels and maps the underlying algorithms onto and load balancing are also considered in the proposed HGP scheme. We have implemented the DQMC simulation

  3. Abstract State Machines Capture Parallel Andreas Blass Yuri Gurevich y

    E-Print Network [OSTI]

    Blass, Andreas R.

    Abstract State Machines Capture Parallel Algorithms Andreas Blass #3; Yuri Gurevich y Technical Microsoft Way Redmond, WA 98052 Abstract We give an axiomatic description of parallel, synchronous algo state machine with a background that provides for multisets. #3; Partially supported by NSF grant DMS

  4. Partitioning strategies for parallel KIVA-4 engine simulations

    SciTech Connect (OSTI)

    Torres, D J [Los Alamos National Laboratory; Kong, S C [IOWA STATE UNIV

    2008-01-01

    Parallel KIVA-4 is described and simulated in four different engine geometries. The Message Passing-Interface (MPl) was used to parallelize KIVA-4. Par itioning strategies ar accesed in light of the fact that cells can become deactivated and activated during the course of an engine simulation which will affect the load balance between processors.

  5. Can Users Play an Effective Role in Parallel Tools Research?

    E-Print Network [OSTI]

    Pancake, Cherri M.

    Can Users Play an Effective Role in Parallel Tools Research? Cherri M. Pancake Department is a cost-effective way of improving both the quality and the acceptability of tool products. In this paper the foundation for parallel tool design. Integrating users changes the basic nature of the software process

  6. THE INHERENT QUEUING DELAY OF PARALLEL PACKET SWITCHES

    E-Print Network [OSTI]

    Attiya, Hagit

    THE INHERENT QUEUING DELAY OF PARALLEL PACKET SWITCHES (Extended Abstract) Hagit Attiya and David {hagit,hdavid}@cs.technion.ac.il Abstract The parallel packet switch (PPS) is extensively used as the core of con- temporary commercial switches. This paper investigates the inherent queuing delay

  7. The Inherent Queuing Delay of Parallel Packet Switches

    E-Print Network [OSTI]

    Hay, David

    The Inherent Queuing Delay of Parallel Packet Switches Hagit Attiya and David Hay Abstract--The parallel packet switch (PPS) extends the inverse multiplexing architecture and is widely used as the core of contemporary commercial switches. This paper investigates the inherent queuing delay introduced by the PPS

  8. Robust Resource Allocations in Parallel Computing Systems: Model and Heuristics

    E-Print Network [OSTI]

    Maciejewski, Anthony A. "Tony"

    Robust Resource Allocations in Parallel Computing Systems: Model and Heuristics Vladimir Shestak1 in parallel computer systems (including heterogeneous clusters) should be allocated to the computational was supported by the Colorado State University Center for Robustness in Computer Systems (funded by the Colorado

  9. Study of Stability Regions in Parallel Connected Boost Converters

    E-Print Network [OSTI]

    Tse, Chi K. "Michael"

    Study of Stability Regions in Parallel Connected Boost Converters Yuehui Huang and Chi K. Tse attractors of parallel connected boost switching converters under a master- slave current sharing scheme. We boost converters. Under the master- slave scheme, one of the converters is the master and the other

  10. Probabilistic Adaptive Load Balancing for Parallel Daniel M. Yellin #1

    E-Print Network [OSTI]

    Paton, Norman

    , Jerusalem, Israel 96951 1 dmy@us.ibm.com Departmento de Computaci´on, CINVESTAV-IPN Av. Inst. Pol. Nal. 2508 D.F, M´exico 07360 2 jbuenabad@cs.cinvestav.mx + School of Computer Science, University partitioned or pipelined parallelism. Partitioned parallelism has the potential to provide scaleable query

  11. System Support for Implicitly Parallel Programming Matthew I. Frank

    E-Print Network [OSTI]

    Frank, Matthew I.

    System Support for Implicitly Parallel Programming Matthew I. Frank Coordinated Science Laboratory Electrical and Computer Engineering University of Illinois at Urbana-Champaign Abstract Implicit sequential semantics, e.g., the C programming lan- guage. System tools convert the parallel algorithms

  12. Application of Parallel Imaging to Murine Magnetic Resonance Imaging 

    E-Print Network [OSTI]

    Chang, Chieh-Wei 1980-

    2012-09-21

    . This dissertation describes foundational level work to enable parallel imaging of mice on a 4.7 Tesla/40 cm bore research scanner. Reducing the size of the hardware setup associated with typical parallel imaging was an integral part of achieving the work, as animal...

  13. Parallel Picoliter RT-PCR Assays Using Microfluidics

    E-Print Network [OSTI]

    Quake, Stephen R.

    Parallel Picoliter RT-PCR Assays Using Microfluidics Joshua S. Marcus,, W. French Anderson The development of microfluidic tools for high-throughput nucleic acid analysis has become a burgeoning area of research in the post-genome era. Here, we have developed a microfluidic chip to perform 72 parallel 450-p

  14. Analyzing Parallelism and Domain Similarities in the MAREC Patent Corpus

    E-Print Network [OSTI]

    Riezler, Stefan

    Analyzing Parallelism and Domain Similarities in the MAREC Patent Corpus Katharina W}@cl.uni-heidelberg.de Abstract. Statistical machine translation of patents requires large a- mounts of sentence-parallel data. Translations of patent text often exist for parts of the patent document, namely title, abstract and claims

  15. On the Interplay of Parallelization, Program Performance, and Energy Consumption

    E-Print Network [OSTI]

    Scarano, Vittorio

    On the Interplay of Parallelization, Program Performance, and Energy Consumption Sangyeun Cho to either minimize the total energy consumption or minimize the energy-delay product. The impact of static through parallel execution of applications, suppressing the power and energy consumption remains an even

  16. A Taxonomy of Parallel Prefix Networks David Harris

    E-Print Network [OSTI]

    Harris, David Money

    A Taxonomy of Parallel Prefix Networks David Harris Harvey Mudd College / Sun Microsystems of logic levels, fanout, and wiring tracks. This paper presents a three-dimensional taxonomy that not only for wide adders. This paper develops a taxonomy of parallel prefix networks based on stages, fanout

  17. A Parallel Visualization Pipeline for Terascale Earthquake Simulations

    E-Print Network [OSTI]

    Ma, Kwan-Liu

    A Parallel Visualization Pipeline for Terascale Earthquake Simulations Hongfeng Yu Kwan-Liu Ma welling@psc.edu ABSTRACT This paper presents a parallel visualization pipeline imple- mented earth- quake and reduce its risk to the general population. The 0 0-7695-2153-3/04 $20.00 (c)2004 IEEE

  18. The Parallel BGL: A Generic Library for Distributed Graph Computations

    E-Print Network [OSTI]

    Lumsdaine, Andrew

    ] and written in a style similar to the C++ Standard Template Library (STL) [38, 46], 1 #12;data types providedThe Parallel BGL: A Generic Library for Distributed Graph Computations Douglas Gregor and Andrew,lums}@osl.iu.edu Abstract This paper presents the Parallel BGL, a generic C++ library for distributed graph computation

  19. A Parallel Jacobi Method for the Takagi Factorization Xiaohong Wang

    E-Print Network [OSTI]

    Qiao, Sanzheng

    A Parallel Jacobi Method for the Takagi Factorization Xiaohong Wang Department of Computing-symmetric matrix. We present a multthreading parallel Jacobi algorithm for computing the Takagi factorization Jacobi method, Multithreading. 1 Introduction A matrix A of order n is symmetric if A = A T . When

  20. An Overview of Parallel Ccomputing Marc Moreno Maza

    E-Print Network [OSTI]

    Moreno Maza, Marc

    (Canada) CS2101 #12;Plan 1 Hardware 2 Types of Parallelism 3 Concurrency Platforms: Three Examples Cilk CUDA MPI #12;Hardware Plan 1 Hardware 2 Types of Parallelism 3 Concurrency Platforms: Three Examples Cilk CUDA MPI #12;Hardware von Neumann Architecture In 1945, the Hungarian mathematician John von

  1. A Hierarchical and Parallel Method for Training Support Vector Machines

    E-Print Network [OSTI]

    Lu, Bao-Liang

    handled by many modules. After training, all the trained modules are integrated into a modular system [4A Hierarchical and Parallel Method for Training Support Vector Machines Yimin Wen1,2 and Baoliang sequential methods need long training time, and some of parallel methods lead to generalization accuracy

  2. Is sex categorization from faces really parallel to face recognition?

    E-Print Network [OSTI]

    Rossion, Bruno

    Is sex categorization from faces really parallel to face recognition? Bruno Rossion Department of face processing (Bruce & Young, 1986), sex processing on faces is a parallel function to individual face recognition. One consequence of the model is thus that sex categorization on faces

  3. Highly Available, Fault-Tolerant, Parallel Dataflows Mehul A. Shah

    E-Print Network [OSTI]

    Hellerstein, Joseph M.

    Highly Available, Fault-Tolerant, Parallel Dataflows Mehul A. Shah U.C. Berkeley mashah@cs.berkeley.edu Joseph M. Hellerstein U.C. Berkeley Intel Research, Berkeley jmh@cs.berkeley.edu Eric Brewer U.C. This delicate inte- gration allows us to tolerate failures of portions of a parallel dataflow without

  4. Automatic Parallelization of Hand Written Automotive Engine Control

    E-Print Network [OSTI]

    Kasahara, Hironori

    Automatic Parallelization of Hand Written Automotive Engine Control Codes Using OSCAR Compiler Dan approach to realize the next- generation automobiles integrated control system. However, automotive-core processors for a long time. This paper proposes to parallelize an automotive engine crankshaft control

  5. Visualization in a Parallel Processing Environment Robert Haimes \\Lambda

    E-Print Network [OSTI]

    Peraire, Jaime

    is becoming US industry's super­ computer. Computational simulations are being developed today that run super­computer class hardware (which includes parallel ma­ chines or a high­speed network of computational methodologies employing visualization and parallel processing for the extraction of information

  6. Broadcasting collective operation contributions throughout a parallel computer

    DOE Patents [OSTI]

    Faraj, Ahmad (Rochester, MN)

    2012-02-21

    Methods, systems, and products are disclosed for broadcasting collective operation contributions throughout a parallel computer. The parallel computer includes a plurality of compute nodes connected together through a data communications network. Each compute node has a plurality of processors for use in collective parallel operations on the parallel computer. Broadcasting collective operation contributions throughout a parallel computer according to embodiments of the present invention includes: transmitting, by each processor on each compute node, that processor's collective operation contribution to the other processors on that compute node using intra-node communications; and transmitting on a designated network link, by each processor on each compute node according to a serial processor transmission sequence, that processor's collective operation contribution to the other processors on the other compute nodes using inter-node communications.

  7. Characterizing and Mitigating Work Time Inflation in Task Parallel Programs

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Olivier, Stephen L.; de Supinski, Bronis R.; Schulz, Martin; Prins, Jan F.

    2013-01-01

    Task parallelism raises the level of abstraction in shared memory parallel programming to simplify the development of complex applications. However, task parallel applications can exhibit poor performance due to thread idleness, scheduling overheads, and work time inflation – additional time spent by threads in a multithreaded computation beyond the time required to perform the same work in a sequential computation. We identify the contributions of each factor to lost efficiency in various task parallel OpenMP applications and diagnose the causes of work time inflation in those applications. Increased data access latency can cause significant work time inflation in NUMAmore »systems. Our locality framework for task parallel OpenMP programs mitigates this cause of work time inflation. Our extensions to the Qthreads library demonstrate that locality-aware scheduling can improve performance up to 3X compared to the Intel OpenMP task scheduler. « less

  8. Transparent runtime parallelization of the R scripting language

    SciTech Connect (OSTI)

    Yoginath, Srikanth B [ORNL

    2011-01-01

    Scripting languages such as R and Matlab are widely used in scientific data processing. As the data volume and the complexity of analysis tasks both grow, sequential data processing using these tools often becomes the bottleneck in scientific workflows. We describe pR, a runtime framework for automatic and transparent parallelization of the popular R language used in statistical computing. Recognizing scripting languages interpreted nature and data analysis codes use pattern, we propose several novel techniques: (1) applying parallelizing compiler technology to runtime, whole-program dependence analysis of scripting languages, (2) incremental code analysis assisted with evaluation results, and (3) runtime parallelization of file accesses. Our framework does not require any modification to either the source code or the underlying R implementation. Experimental results demonstrate that pR can exploit both task and data parallelism transparently and overall has better performance as well as scalability compared to an existing parallel R package that requires code modification.

  9. Parallel architecture for real-time simulation. Master's thesis

    SciTech Connect (OSTI)

    Cockrell, C.D.

    1989-01-01

    This thesis is concerned with the development of a very fast and highly efficient parallel computer architecture for real-time simulation of continuous systems. Currently, several parallel processing systems exist that may be capable of executing a complex simulation in real-time. These systems are examined and the pros and cons of each system discussed. The thesis then introduced a custom-designed parallel architecture based upon The University of Alabama's OPERA architecture. Each component of this system is discussed and rationale presented for its selection. The problem selected, real-time simulation of the Space Shuttle Main Engine for the test and evaluation of the proposed architecture, is explored, identifying the areas where parallelism can be exploited and parallel processing applied. Results from the test and evaluation phase are presented and compared with the results of the same problem that has been processed on a uniprocessor system.

  10. Parallel visualization and analysis with paraview on a Cray XT4

    SciTech Connect (OSTI)

    Ahrens, James P [Los Alamos National Laboratory; Patchett, John M [Los Alamos National Laboratory; Pugmire, David L [ORNL; Ahern, Sean [ORNL

    2010-01-01

    Scientific data sets produced by modern supercomputers like ORNL's Cray XT 4, Jaguar, can be extremely large, making visualization and analysis more difficult as moving large resultant data to dedicated analysis systems can be prohibitively expensive. We share our continuing work of integrating a parallel visualization system, ParaView, on ORNL's Jaguar system and our efforts to enable extreme scale interactive data visualization and analysis. We will discuss porting challenges and present performance numbers. Jaguar is a Cray XT4 with 7,832 compute nodes each with 4 cores and 8GB of memory, located in Oak Ridge, Tennessee. Jaguar is currently ranked No.8 in the Top 500. Jaguar, and other machines like it, enable increasingly larger data sets. Whether scientists are producing extremely massive data or small data they still have a requirement for analysis. Analysis is often difficult for larger data and it is further complicated when the user is distant to the data. Data sets that are too large to ship and/or analyze on a single desktop require a parallel analysis tool and a high performance computer to run on. Running ParaView interactively on Jaguar is a positive improvement for both local and remote users. We have shown that it is feasible for our user at LANL to visualize his simulation data created on jaguar. Local users may face fewer obstacles and get improved performance, due to their higher bandwidth to Jaguar. For future work, we would like to see higher priority queues that enable interactive visualization. A more interactive user-friendly qsub that estimates time to allocation would be very useful. Hopefully, our work will lead to more users attempting interactive visualization on Jaguar, resulting in quicker turnaround times for visualization and analysis. As users migrate to using supercomputing platforms for visualization, we expect future research possibilities in this area.

  11. Stochastic Acceleration in Relativistic Parallel Shocks

    E-Print Network [OSTI]

    Joni J. P. Virtanen; Rami Vainio

    2004-11-08

    (abridged) We present results of test-particle simulations on both the first and the second order Fermi acceleration at relativistic parallel shock waves. We consider two scenarios for particle injection: (i) particles injected at the shock front, then accelerated at the shock by the first order mechanism and subsequently by the stochastic process in the downstream region; and (ii) particles injected uniformly throughout the downstream region to the stochastic process. We show that regardless of the injection scenario, depending on the magnetic field strength, plasma composition, and the employed turbulence model, the stochastic mechanism can have considerable effects on the particle spectrum on temporal and spatial scales too short to be resolved in extragalactic jets. Stochastic acceleration is shown to be able to produce spectra that are significantly flatter than the limiting case of particle energy spectral index -1 of the first order mechanism. Our study also reveals a possibility of re-acceleration of the stochastically accelerated spectrum at the shock, as particles at high energies become more and more mobile as their mean free path increases with energy. Our findings suggest that the role of the second order mechanism in the turbulent downstream of a relativistic shock with respect to the first order mechanism at the shock front has been underestimated in the past, and that the second order mechanism may have significant effects on the form of the particle spectra and its evolution.

  12. Astrophysics Research Projects:Astrophysics Research Projects: massive star winds, x-ray emission, theoretical models,massive star winds, x-ray emission, theoretical models,

    E-Print Network [OSTI]

    Cohen, David

    Astrophysics Research Projects:Astrophysics Research Projects: massive star winds, x-ray emission, theoretical models,massive star winds, x-ray emission, theoretical models, spectroscopy, laboratory plasma-drivenhave powerful radiation-driven stellar windsstellar winds.. etaeta CarinaCarina #12;TheThe ChandraChandra X

  13. Enhancing the Performance of a Multiplayer Game by Using a Parallelizing Compiler

    E-Print Network [OSTI]

    Kasahara, Hironori

    Enhancing the Performance of a Multiplayer Game by Using a Parallelizing Compiler Yasir I. M. Al performance enhancement in Video Games when using parallelizing compilers and the difficulties involved parallelizing compilers in extracting parallelism. Next, the program is compiled using a parallelizing compiler

  14. Development of Large Scale High Performance Applications with a Parallelizing Compiler

    E-Print Network [OSTI]

    Vlad, Gregorio

    Development of Large Scale High Performance Applications with a Parallelizing Compiler B. DI parallel computations, and lack of robustness of parallelizing HPF compilers in handling large sized codes directives, into explicitly parallel code, by means of parallelizing compilers. This method is not only

  15. THE MASSIVE SATELLITE POPULATION OF MILKY-WAY-SIZED GALAXIES

    SciTech Connect (OSTI)

    Rodriguez-Puebla, Aldo; Avila-Reese, Vladimir; Drory, Niv, E-mail: apuebla@astro.unam.mx [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A. P. 70-264, 04510 Mexico, DF (Mexico)

    2013-08-20

    Several occupational distributions for satellite galaxies more massive than m{sub *} Almost-Equal-To 4 Multiplication-Sign 10{sup 7} M{sub Sun} around Milky-Way (MW)-sized hosts are presented and used to predict the internal dynamics of these satellites as a function of m{sub *}. For the analysis, a large galaxy group mock catalog is constructed on the basis of (sub)halo-to-stellar mass relations fully constrained with currently available observations, namely the galaxy stellar mass function decomposed into centrals and satellites, and the two-point correlation functions at different masses. We find that 6.6% of MW-sized galaxies host two satellites in the mass range of the Small and Large Magellanic Clouds (SMC and LMC, respectively). The probabilities of the MW-sized galaxies having one satellite equal to or larger than the LMC, two satellites equal to or larger than the SMC, or three satellites equal to or larger than Sagittarius (Sgr) are Almost-Equal-To 0.26, 0.14, and 0.14, respectively. The cumulative satellite mass function of the MW, N{sub s} ({>=}m{sub *}) , down to the mass of the Fornax dwarf is within the 1{sigma} distribution of all the MW-sized galaxies. We find that MW-sized hosts with three satellites more massive than Sgr (as the MW) are among the most common cases. However, the most and second most massive satellites in these systems are smaller than the LMC and SMC by roughly 0.7 and 0.8 dex, respectively. We conclude that the distribution N{sub s} ({>=}m{sub *}) for MW-sized galaxies is quite broad, the particular case of the MW being of low frequency but not an outlier. The halo mass of MW-sized galaxies correlates only weakly with N{sub s} ({>=}m{sub *}). Then, it is not possible to accurately determine the MW halo mass by means of its N{sub s} ({>=}m{sub *}); from our catalog, we constrain a lower limit of 1.38 Multiplication-Sign 10{sup 12} M{sub Sun} at the 1{sigma} level. Our analysis strongly suggests that the abundance of massive subhalos should agree with the abundance of massive satellites in all MW-sized hosts, i.e., there is not a missing (massive) satellite problem for the {Lambda}CDM cosmology. However, we confirm that the maximum circular velocity, v{sub max}, of the subhalos of satellites smaller than m{sub *} {approx} 10{sup 8} M{sub Sun} is systematically larger than the v{sub max} inferred from current observational studies of the MW bright dwarf satellites; different from previous works, this conclusion is based on an analysis of the overall population of MW-sized galaxies. Some pieces of evidence suggest that the issue could refer only to satellite dwarfs but not to central dwarfs, then environmental processes associated with dwarfs inside host halos combined with supernova-driven core expansion should be on the basis of the lowering of v{sub max}.

  16. Ionized gas kinematics and massive star formation in NGC 1530

    E-Print Network [OSTI]

    A. Zurita; M. Relano; J. E. Beckman; J. H. Knapen

    2003-07-11

    We present emission line mapping of the strongly barred galaxy NGC 1530 obtained from Fabry-Perot interferometry in Halpha, at significantly enhanced angular resolution compared with published studies. The main point of the work is to examine in detail the non-circular components of the velocity field of the gas, presumably induced by the strongly non-axisymmetric gravitational potential of the bar. These reveal quasi-elliptical motions with speeds of order 100 km/s aligned with the bar. It also shows how these flows swing in towards and around the nucleus as they cross a circumnuclear resonance, from the dominant "x1 orbits" outside the resonance to "x2 orbits" within it. Comparing cross-sections of the residual velocity map along and across the bar with the Halpha intensity map indicates a systematic offset between regions of high non-circular velocity and massive star formation. To investigate further we produce velocity gradient maps along and across the bar. These illustrate very nicely the shear compression of the gas, revealed by the location of the dust lanes along loci of maximum velocity gradient perpendicular to the bar. They also show clearly how shear acts to inhibit massive star formation, whereas shocks act to enhance it. Although the inhibiting effect of gas shear flow on star formation has long been predicted, this is the clearest observational illustration so far of the effect. It is also the clearest evidence that dust picks out shock-induced inflow along bars. These observations should be of considerable interest to those modelling massive star formation in general.

  17. Stellar populations of massive elliptical galaxies in very rich clusters

    E-Print Network [OSTI]

    C. Carretero; A. Vazdekis; J. E. Beckman; .

    2006-12-05

    We present a detailed stellar population analysis of 27 massive elliptical galaxies within 4 very rich clusters at redshift z~0.2: A115, A655, A963 and A2111. Using the new, high-resolution stellar populations models developed in our group, we obtained accurate estimates of the mean luminosity-weighted ages and relative abundances of CN, Mg and Fe. We have found that [CN/H] and [Mg/H] are correlated with sigma while [Fe/H] and Log(age) are not. In addition, both abundance ratios [CN/Fe] and [Mg/Fe] increase with sigma. Furthermore, the [CN/H]-sigma and [CN/Fe]-sigma slopes are steeper for galaxies in very rich clusters than those in the less dense Virgo and Coma clusters. On the other hand, [Mg/H]-sigma and [Mg/Fe]-sigma slopes keep constant as functions of the environment. Our results are compatible with a scenario in which the stellar populations of massive elliptical galaxies, independently of their environment and mass, had formation timescales shorter than ~1 Gyr. This result implies that massive elliptical galaxies have evolved passively since, at least, as long ago as z~2. For a given galaxy mass the duration of star formation is shorter in those galaxies belonging to more dense environments; whereas the mass-metallicity relation appears to be also a function of the cluster properties: the denser the environment is, the steeper are the correlations. Finally, we show that the abundance ratios [CN/Fe] and [Mg/Fe] are the key "chemical clocks" to infer the star formation history timescales in ellipticals. In particular, [Mg/Fe] provides an upper limit for those formation timescales, while [CN/Fe] apperars to be the most suitable parameter to resolve them in elliptical galaxies with sigma<300 km/s.

  18. An integrated approach to improving the parallel applications development process

    SciTech Connect (OSTI)

    Rasmussen, Craig E [Los Alamos National Laboratory; Watson, Gregory R [IBM; Tibbitts, Beth R [IBM

    2009-01-01

    The development of parallel applications is becoming increasingly important to a broad range of industries. Traditionally, parallel programming was a niche area that was primarily exploited by scientists trying to model extremely complicated physical phenomenon. It is becoming increasingly clear, however, that continued hardware performance improvements through clock scaling and feature-size reduction are simply not going to be achievable for much longer. The hardware vendor's approach to addressing this issue is to employ parallelism through multi-processor and multi-core technologies. While there is little doubt that this approach produces scaling improvements, there are still many significant hurdles to be overcome before parallelism can be employed as a general replacement to more traditional programming techniques. The Parallel Tools Platform (PTP) Project was created in 2005 in an attempt to provide developers with new tools aimed at addressing some of the parallel development issues. Since then, the introduction of a new generation of peta-scale and multi-core systems has highlighted the need for such a platform. In this paper, we describe some of the challenges facing parallel application developers, present the current state of PTP, and provide a simple case study that demonstrates how PTP can be used to locate a potential deadlock situation in an MPI code.

  19. Translation invariant time-dependent massive gravity: Hamiltonian analysis

    SciTech Connect (OSTI)

    Mourad, Jihad; Steer, Danièle A.; Noui, Karim E-mail: karim.noui@lmpt.univ-tours.fr

    2014-09-01

    The canonical structure of the massive gravity in the first order moving frame formalism is studied. We work in the simplified context of translation invariant fields, with mass terms given by general non-derivative interactions, invariant under the diagonal Lorentz group, depending on the moving frame as well as a fixed reference frame. We prove that the only mass terms which give 5 propagating degrees of freedom are the dRGT mass terms, namely those which are linear in the lapse. We also complete the Hamiltonian analysis with the dynamical evolution of the system.

  20. Exotic massive hadrons and ultrahigh energy cosmic rays

    SciTech Connect (OSTI)

    Albuquerque, I.F. [Department of Astronomy and Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Astronomy and Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Farrar, G.R. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855 (United States)] [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855 (United States); Kolb, E.W. [NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)] [NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); [Department of Astronomy and Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

    1999-01-01

    We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that masses in excess of about 50 GeV are inconsistent with the highest energy event observed. We also estimate that with sufficient statistics a uhecron of mass as low as 10 GeV may be distinguished from a proton. {copyright} {ital 1998} {ital The American Physical Society}

  1. Repulsive gravity near naked singularities and point massive particles

    E-Print Network [OSTI]

    J. W. Maluf

    2014-05-05

    We investigate the existence of repulsive gravitational acceleration near naked singularities. The investigation is carried out by means of the acceleration tensor, which is a coordinate invariant object. We find that the gravitational acceleration is repulsive in the vicinity of the origin in the Reissner-Nordstr{\\o}m and in the Kerr space-times, and attractive at large distances in the expected Newtonian way. We further address the space-time of a point massive particle, which also exhibits repulsive effects near the origin.

  2. Cosmic expansion histories in massive bigravity with symmetric matter coupling

    SciTech Connect (OSTI)

    Enander, Jonas; Mörtsell, Edvard [Oskar Klein Center, Stockholm University, Albanova University Center, 106 91 Stockholm (Sweden); Solomon, Adam R. [DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Rd., Cambridge CB3 0WA (United Kingdom); Akrami, Yashar, E-mail: enander@fysik.su.se, E-mail: a.r.solomon@damtp.cam.ac.uk, E-mail: yashar.akrami@astro.uio.no, E-mail: edvard@fysik.su.se [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)

    2015-01-01

    We study the cosmic expansion history of massive bigravity with a viable matter coupling which treats both metrics on equal footing. We derive the Friedmann equation for the effective metric through which matter couples to the two metrics, and study its solutions. For certain parameter choices, the background cosmology is identical to that of ?CDM. More general parameters yield dynamical dark energy, which can still be in agreement with observations of the expansion history. We study specific parameter choices of interest, including minimal models, maximally-symmetric models, and a candidate partially-massless theory.

  3. Reappraising the concept of massive transfusion in trauma

    E-Print Network [OSTI]

    Stanworth, Simon J.; Morris, Timothy P.; Gaarder, Christine; Goslings, J. Carel; Maegele, Marc; Cohen, Mitchell J.; Koenig, Thomas C.; Davenport, Ross A.; Pittet, Jean-Francois; Johannson, Par I.; Allard, Shubha; Johnson, Tony; Brohi, Karim

    2010-12-30

    transfusion in trauma Simon J Stanworth1*, Timothy P Morris2, Christine Gaarder3, J Carel Goslings4, Marc Maegele5, Mitchell J Cohen6, Thomas C König7, Ross A Davenport7, Jean-Francois Pittet8, Pär I Johansson9, Shubha Allard10, Tony Johnson2,11, Karim Brohi7... in Haematology, Stainsby D, MacLennan S, Thomas D, Isaac J, Hamilton PJ: Guidelines on the management of massive blood loss. Br J Haematol 2006, 135:634-641. 3. Geeraedts LM Jr, Demiral H, Schaap NP, Kamphuisen PW, Pompe JC, Frölke JP: ’Blind’ transfusion...

  4. Massive dark photons in a Higgs portal model

    E-Print Network [OSTI]

    Dimiter Hadjimichef

    2016-01-03

    An extension of the Standard Model with a hidden sector which consists of gauge singlets (a Dirac fermion $\\chi$ and a scalar $S$) plus a vector boson $V_\\mu$ (dark massive photon) is studied. The singlet scalar interacts with the Standard Model sector through the triple and quartic scalar interactions, while the singlet fermion and vector boson field interact with the Standard Model only via the singlet scalar. The scalar field generates the vector boson's mass. Perspectives for future $e^{-}e^{+}$ colliders is considered.

  5. Massive dark photons in a Higgs portal model

    E-Print Network [OSTI]

    Hadjimichef, Dimiter

    2016-01-01

    An extension of the Standard Model with a hidden sector which consists of gauge singlets (a Dirac fermion $\\chi$ and a scalar $S$) plus a vector boson $V_\\mu$ (dark massive photon) is studied. The singlet scalar interacts with the Standard Model sector through the triple and quartic scalar interactions, while the singlet fermion and vector boson field interact with the Standard Model only via the singlet scalar. The scalar field generates the vector boson's mass. Perspectives for future $e^{-}e^{+}$ colliders is considered.

  6. Solitary Waves in Massive Nonlinear S^N-Sigma Models

    E-Print Network [OSTI]

    A. Alonso Izquierdo; M. Á. González León; M. de la Torre Mayado

    2010-02-09

    The solitary waves of massive (1+1)-dimensional nonlinear S^N-sigma models are unveiled. It is shown that the solitary waves in these systems are in one-to-one correspondence with the separatrix trajectories in the repulsive N-dimensional Neumann mechanical problem. There are topological (heteroclinic trajectories) and non-topological (homoclinic trajectories) kinks. The stability of some embedded sine-Gordon kinks is discussed by means of the direct estimation of the spectra of the second-order fluctuation operators around them, whereas the instability of other topological and non-topological kinks is established applying the Morse index theorem.

  7. Massive photons and Dirac monopoles: electric condensate and magnetic confinement

    E-Print Network [OSTI]

    M. S. Guimaraes; R. Rougemont; C. Wotzasek; C. A. D. Zarro

    2013-05-13

    We use the generalized Julia-Toulouse approach (GJTA) for condensation of topological currents (charges or defects) to argue that massive photons can coexist consistently with Dirac monopoles. The Proca theory is obtained here via GJTA as a low energy effective theory describing an electric condensate and the mass of the vector boson is responsible for generating a Meissner effect which confines the magnetic defects in monopole-antimonopole pairs connected by physical open magnetic vortices described by Dirac brane invariants, instead of Dirac strings.

  8. Holographic Polarons, the Metal-Insulator Transition and Massive Gravity

    E-Print Network [OSTI]

    Matteo Baggioli; Oriol Pujolas

    2014-11-19

    Massive gravity is holographically dual to `realistic' materials with momentum relaxation. The dual graviton potential encodes the phonon dynamics and it allows for a much broader diversity than considered so far. We construct a simple family of isotropic and homogeneous materials that exhibit an interaction-driven Metal-Insulator transition. The transition is triggered by the formation of polarons -- phonon-electron quasi-bound states that dominate the conductivities, shifting the spectral weight above a mass gap. We characterize the polaron gap, width and dispersion.

  9. A New Massive Type IIA Supergravity From Compactification

    E-Print Network [OSTI]

    P. S. Howe; N. D. Lambert; P. C. West

    1997-08-05

    We consider the most general form for eleven dimensional supersymmetry compatible with on-shell superfields. This allows for the introduction of a conformal Spin(1,10) connection. In eleven dimensional Minkowski space this modification is trivial and can be removed by a field redefinition, however, upon compactification on S^1 it is possible to introduce a non-trivial `Wilson line'. The resulting ten dimensional supergravity has massive 1-form and 3-form potentials and a cosmological constant. This theory does not possess a supersymmetric eightbrane soliton but it does admit a supersymmetric non-static cosmological solution.

  10. Petascale Parallelization of the Gyrokinetic Toroidal Code

    SciTech Connect (OSTI)

    Ethier, Stephane; Adams, Mark; Carter, Jonathan; Oliker, Leonid

    2010-05-01

    The Gyrokinetic Toroidal Code (GTC) is a global, three-dimensional particle-in-cell application developed to study microturbulence in tokamak fusion devices. The global capability of GTC is unique, allowing researchers to systematically analyze important dynamics such as turbulence spreading. In this work we examine a new radial domain decomposition approach to allow scalability onto the latest generation of petascale systems. Extensive performance evaluation is conducted on three high performance computing systems: the IBM BG/P, the Cray XT4, and an Intel Xeon Cluster. Overall results show that the radial decomposition approach dramatically increases scalability, while reducing the memory footprint - allowing for fusion device simulations at an unprecedented scale. After a decade where high-end computing (HEC) was dominated by the rapid pace of improvements to processor frequencies, the performance of next-generation supercomputers is increasingly differentiated by varying interconnect designs and levels of integration. Understanding the tradeoffs of these system designs is a key step towards making effective petascale computing a reality. In this work, we examine a new parallelization scheme for the Gyrokinetic Toroidal Code (GTC) [?] micro-turbulence fusion application. Extensive scalability results and analysis are presented on three HEC systems: the IBM BlueGene/P (BG/P) at Argonne National Laboratory, the Cray XT4 at Lawrence Berkeley National Laboratory, and an Intel Xeon cluster at Lawrence Livermore National Laboratory. Overall results indicate that the new radial decomposition approach successfully attains unprecedented scalability to 131,072 BG/P cores by overcoming the memory limitations of the previous approach. The new version is well suited to utilize emerging petascale resources to access new regimes of physical phenomena.

  11. Xyce Parallel Electronic Simulator : users' guide, version 4.1.

    SciTech Connect (OSTI)

    Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Keiter, Eric Richard; Pawlowski, Roger Patrick

    2009-02-01

    This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: (1) Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers. (2) Improved performance for all numerical kernels (e.g., time integrator, nonlinear and linear solvers) through state-of-the-art algorithms and novel techniques. (3) Device models which are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only). (4) Object-oriented code design and implementation using modern coding practices that ensure that the Xyce Parallel Electronic Simulator will be maintainable and extensible far into the future. Xyce is a parallel code in the most general sense of the phrase - a message passing parallel implementation - which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows. The development of Xyce provides a platform for computational research and development aimed specifically at the needs of the Laboratory. With Xyce, Sandia has an 'in-house' capability with which both new electrical (e.g., device model development) and algorithmic (e.g., faster time-integration methods, parallel solver algorithms) research and development can be performed. As a result, Xyce is a unique electrical simulation capability, designed to meet the unique needs of the laboratory.

  12. Xyce parallel electronic simulator : users' guide. Version 5.1.

    SciTech Connect (OSTI)

    Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Keiter, Eric Richard; Pawlowski, Roger Patrick

    2009-11-01

    This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: (1) Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers. (2) Improved performance for all numerical kernels (e.g., time integrator, nonlinear and linear solvers) through state-of-the-art algorithms and novel techniques. (3) Device models which are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only). (4) Object-oriented code design and implementation using modern coding practices that ensure that the Xyce Parallel Electronic Simulator will be maintainable and extensible far into the future. Xyce is a parallel code in the most general sense of the phrase - a message passing parallel implementation - which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows. The development of Xyce provides a platform for computational research and development aimed specifically at the needs of the Laboratory. With Xyce, Sandia has an 'in-house' capability with which both new electrical (e.g., device model development) and algorithmic (e.g., faster time-integration methods, parallel solver algorithms) research and development can be performed. As a result, Xyce is a unique electrical simulation capability, designed to meet the unique needs of the laboratory.

  13. Parallel Hall effect from 3D single-component metamaterials

    E-Print Network [OSTI]

    Kern, Christian; Wegener, Martin

    2015-01-01

    We propose a class of three-dimensional metamaterial architectures composed of a single doped semiconductor (e.g., n-Si) in air or vacuum that lead to unusual effective behavior of the classical Hall effect. Using an anisotropic structure, we numerically demonstrate a Hall voltage that is parallel---rather than orthogonal---to the external static magnetic-field vector ("parallel Hall effect"). The sign of this parallel Hall voltage can be determined by a structure parameter. Together with the previously demonstrated positive or negative orthogonal Hall voltage, we demonstrate four different sign combinations

  14. TECA: A Parallel Toolkit for Extreme Climate Analysis

    SciTech Connect (OSTI)

    Prabhat, Mr; Ruebel, Oliver; Byna, Surendra; Wu, Kesheng; Li, Fuyu; Wehner, Michael; Bethel, E. Wes

    2012-03-12

    We present TECA, a parallel toolkit for detecting extreme events in large climate datasets. Modern climate datasets expose parallelism across a number of dimensions: spatial locations, timesteps and ensemble members. We design TECA to exploit these modes of parallelism and demonstrate a prototype implementation for detecting and tracking three classes of extreme events: tropical cyclones, extra-tropical cyclones and atmospheric rivers. We process a modern TB-sized CAM5 simulation dataset with TECA, and demonstrate good runtime performance for the three case studies.

  15. Massive Stars in the W33 Giant Molecular Complex

    E-Print Network [OSTI]

    Messineo, Maria; Figer, Donald F; Kudritzki, Rolf-Peter; Najarro, Francisco; Rich, R Michael; Menten, Karl M; Ivanov, Valentin D; Valenti, Elena; Trombley, Christine; Chen, C -H Rosie; Davies, Ben

    2015-01-01

    Rich in HII regions, giant molecular clouds are natural laboratories to study massive stars and sequential star formation. The Galactic star forming complex W33 is located at l=~12.8deg and at a distance of 2.4 kpc, has a size of ~10 pc and a total mass of (~0.8 - ~8.0) X 10^5 Msun. The integrated radio and IR luminosity of W33 - when combined with the direct detection of methanol masers, the protostellar object W33A, and protocluster embedded within the radio source W33 main - mark the region out as a site of vigorous ongoing star formation. In order to assess the long term star formation history, we performed an infrared spectroscopic search for massive stars, detecting for the first time fourteen early-type stars, including one WN6 star and four O4-7 stars. The distribution of spectral types suggests that this population formed during the last ~2-4 Myr, while the absence of red supergiants precludes extensive star formation at ages 6-30 Myr. This activity appears distributed throughout the region and does ...

  16. Do you know the extinction in your young massive cluster?

    E-Print Network [OSTI]

    De Marchi, Guido; Sabbi, Elena

    2015-01-01

    Up to ages of ~100 Myr, massive clusters are still swamped in large amounts of gas and dust, with considerable and uneven levels of extinction. At the same time, large grains (ices?) produced by type II supernovae profoundly alter the interstellar medium (ISM), thus resulting in extinction properties very different from those of the diffuse ISM. To obtain physically meaningful parameters of stars, from basic luminosities and effective temperatures to masses and ages, we must understand and measure the local extinction law. This problem affects all the massive young clusters discussed in his volume. We have developed a powerful method to unambiguously determine the extinction law in an uniform way across a cluster field, using multi-band photometry of red giant stars belonging to the red clump (RC). In the Large Magellanic Cloud, with about 20 RC stars per arcmin^2, we can easily derive a solid and self-consistent absolute extinction curve over the entire wavelength range of the photometry. Here, we present th...

  17. Massive disk outflows mediated by extreme magnetic fields

    E-Print Network [OSTI]

    Shiber, Sagiv; Soker, Noam

    2015-01-01

    We argue that magnetic fields amplified within a very high accretion-rate disk around main sequence stars can lead to the formation of massive bipolar outflows that can remove most of the disk's mass and energy. This efficient directional removal of energy and mass allows the high accretion-rate disk to be built. We construct thick disks where the magnetic fields are amplified by an Alpha-Omega dynamo in the disk, bringing the fluctuating components of the magnetic field to be much stronger than the large-scale component. By examining the possible activity of the magnetic fields we conclude that main sequence stars can accrete mass at very high rates, up to 0.01Mo/yr for solar type stars, and up to 1Mo/yr for very massive stars. Such energetic outflows can account for the powering of some eruptive objects, such as merging main sequence stars, major eruptions of luminous blue variables, such as the Great Eruption of Eta Carinae, and other intermediate luminosity optical transients (ILOTs; Red Novae; Red Transi...

  18. Endpoint-based parallel data processing with non-blocking collective instructions in a parallel active messaging interface of a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J; Blocksome, Michael A; Cernohous, Bob R; Ratterman, Joseph D; Smith, Brian E

    2014-11-11

    Endpoint-based parallel data processing with non-blocking collective instructions in a PAMI of a parallel computer is disclosed. The PAMI is composed of data communications endpoints, each including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task. The compute nodes are coupled for data communications through the PAMI. The parallel application establishes a data communications geometry specifying a set of endpoints that are used in collective operations of the PAMI by associating with the geometry a list of collective algorithms valid for use with the endpoints of the geometry; registering in each endpoint in the geometry a dispatch callback function for a collective operation; and executing without blocking, through a single one of the endpoints in the geometry, an instruction for the collective operation.

  19. Effective Low-Energy Gravitational Potential for Slow Fermions Coupled to Linearised Massive Gravity

    E-Print Network [OSTI]

    Ivanov, A N; Wellenzohn, M

    2015-01-01

    We analyse the Dirac equation for slow fermions coupled to linearised massive gravity above the Minkowski background and derive the effective low-energy gravitational potential. The obtained results can be used in terrestrial laboratories for the detection of gravitational waves and fluxes of massive gravitons emitted by cosmological objects. We also calculate the neutron spin precession within linearised massive gravity, which in principle can be measured by neutron interferometers.

  20. Earthquake Ground Motion Modeling on Parallel Computers Hesheng Bao

    E-Print Network [OSTI]

    California at Berkeley, University of

    numerical methods for applying seismic forces, incorporating absorbing boundaries, and solving unstructured PDE solvers, parallelizing compilers, seismic wave propagation, strong ground motion. 1 be designed to resist earthquakes and existing structures be retrofitted as necessary. Assessing the free

  1. Parallel Performance of Some Two-Level ASPIN Algorithms

    E-Print Network [OSTI]

    Cai, Xiao-Chuan

    Parallel Performance of Some Two-Level ASPIN Algorithms Leszek Marcinkowski1 and Xiao-Chuan Cai2 1 Marcinkowski and Xiao-Chuan Cai preconditioned inexact Newton methods (ASPIN) were recently proposed in Cai

  2. Control system design for a parallel hybrid electric vehicle 

    E-Print Network [OSTI]

    Buntin, David Leighton

    1994-01-01

    This thesis addresses the design of control systems for a parallel hybrid electric drive train which is an alternative to conventional passenger vehicles. The principle components of the drive train are a small internal combustion engine...

  3. Distributed Point Objects: A new concept for parallel nite elements

    E-Print Network [OSTI]

    Wieners, Christian

    , S. Diebels, W. Ehlers: Parallel 3-d simulations for porous media models in soil mechanics, Comput, porous media simulation, soil mechanics Preprint submitted to Elsevier Science 28 February 2003 #12; 1

  4. Reducing Concurrency Bottlenecks in Parallel I/O Workloads

    SciTech Connect (OSTI)

    Manzanares, Adam C. [Los Alamos National Laboratory; Bent, John M. [Los Alamos National Laboratory; Wingate, Meghan [Los Alamos National Laboratory

    2011-01-01

    To enable high performance parallel checkpointing we introduced the Parallel Log Structured File System (PLFS). PLFS is middleware interposed on the file system stack to transform concurrent writing of one application file into many non-concurrently written component files. The promising effectiveness of PLFS makes it important to examine its performance for workloads other than checkpoint capture, notably the different ways that state snapshots may be later read, to make the case for using PLFS in the Exascale I/O stack. Reading a PLFS file involved reading each of its component files. In this paper we identify performance limitations on broader workloads in an early version of PLFS, specifically the need to build and distribute an index for the overall file, and the pressure on the underlying parallel file system's metadata server, and show how PLFS's decomposed components architecture can be exploited to alleviate bottlenecks in the underlying parallel file system.

  5. Some applications of pipelining techniques in parallel scientific computing 

    E-Print Network [OSTI]

    Deng, Yuanhua

    1996-01-01

    columnwise partitioning schemes. For chasing algorithms, in addition to the pipelining, we apply block-cyclic partitioning, group message-passing techniques to enhance the performance of the pipelined parallel algorithms. The numerical results for the use...

  6. Scioto: A Framework for Global-ViewTask Parallelism

    SciTech Connect (OSTI)

    Dinan, James S.; Krishnamoorthy, Sriram; Larkins, D. B.; Nieplocha, Jaroslaw; Sadayappan, Ponnuswamy

    2008-09-09

    We introduce Scioto, Shared Collections of Task Objects, a framework for supporting task-parallelism in one-sided and global-view parallel programming models. Scioto provides lightweight, locality aware dynamic load balancing and interoperates with existing parallel models including MPI, SHMEM, CAF, and Global Arrays. Through task parallelism, the Scioto framework provides a solution for overcoming load imbalance and heterogeneity as well as dynamic mapping of computation onto emerging multicore architectures. In this paper, we present the design and implementation of the Scioto framework and demonstrate its effectiveness on the Unbalanced Tree Search (UTS) benchmark and two quantum chemistry codes: the closed shell Self-Consistent Field (SCF) method and a sparse tensor contraction kernel extracted from a coupled cluster computation. We explore the efficiency and scalability of Scioto through these sample applications and demonstrate that is offers low overhead, achieves good performance on heterogeneous and multicore clusters, and scales to hundreds of processors.

  7. A parallel hypothesis method of autonomous underwater vehicle navigation

    E-Print Network [OSTI]

    LaPointe, Cara Elizabeth Grupe

    2009-01-01

    This research presents a parallel hypothesis method for autonomous underwater vehicle navigation that enables a vehicle to expand the operating envelope of existing long baseline acoustic navigation systems by incorporating ...

  8. Scheduling on the MasPar SIMD parallel computer 

    E-Print Network [OSTI]

    Perkins, Keith Douglas

    1995-01-01

    This thesis studies the feasibility of a task scheduler for a parallel operating system. After analyzing several task scheduling algorithms, the highest level first algorithm was chosen. This algorithm has been empirically found to build schedules...

  9. Design and evaluation of the Hamal parallel computer

    E-Print Network [OSTI]

    Grossman, J. P., 1973-

    2003-01-01

    Parallel shared-memory machines with hundreds or thousands of processor-memory nodes have been built; in the future we will see machines with millions or even billions of nodes. Associated with such large systems is a new ...

  10. Design and Evaluation of the Hamal Parallel Computer

    E-Print Network [OSTI]

    Grossman, J.P.

    2002-12-05

    Parallel shared-memory machines with hundreds or thousands of processor-memory nodes have been built; in the future we will see machines with millions or even billions of nodes. Associated with such large systems is a new ...

  11. Introduction of static load balancing in incremental parallel programming

    E-Print Network [OSTI]

    Goodman, J.

    Goodman,J. O'Donnell,J.T. Proceedings of Euro-Par 2001 Parallel Processing, Lecture Notes in Computer Science, pp. 535-539, vol. 2150 pp 535-539 Springer

  12. A network based model for heterogeneous parallel computation 

    E-Print Network [OSTI]

    Sathye, Adwait B.

    1993-01-01

    The computational requirements of science and engineering demand computational resources orders of magnitude of the current day sequential machines. Most of the research effort has been concentrated upon the creation of parallel algorithms...

  13. Speeding up Parallel Graph Coloring Assefaw H. Gebremedhin1,

    E-Print Network [OSTI]

    Manne, Fredrik

    Speeding up Parallel Graph Coloring Assefaw H. Gebremedhin1, , Fredrik Manne2 , and Tom Woods2 1. Gebremedhin, Fredrik Manne, and Tom Woods However, in practice greedy sequential coloring heuristics have been

  14. A Comprehensive Look at High Performance Parallel I/O

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of calculations per second-generating a tsunami of data along the way. In this era of "big data," high performance parallel IO-the way disk drives efficiently read and write...

  15. Array-Based Hierarchical Mesh Generation in Parallel | Argonne...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Array-Based Hierarchical Mesh Generation in Parallel Event Sponsor: Mathematics and Computing Science Seminar Start Date: Aug 20 2015 - 1:00am BuildingRoom: Building 240Room 4301...

  16. Natural convection flows in parallel connected vertical channels with boiling

    E-Print Network [OSTI]

    Eselgroth, Peter Ward

    1967-01-01

    The steady-state flow configuration in an array of parallel heated channels is examined with the objective of predicting the behavior of a reactor during a loss of flow accident. A method of combining the results of single ...

  17. Optimized control studies of a parallel hybrid electric vehicle 

    E-Print Network [OSTI]

    Bougler, Benedicte Bernadette

    1995-01-01

    This thesis addresses the development of a control scheme to maximize automobile fuel economy and battery state-of-charge (SOC) while meeting exhaust emission standards for parallel hybrid electric vehicles, which are an alternative to conventional...

  18. Parallel Processing Letters fc World Scientific Publishing Company

    E-Print Network [OSTI]

    Mavronicolas, Marios

    Parallel Processing Letters fc World Scientific Publishing Company THE PRICE OF ANARCHY of Computer Science, Electrical Engineering and Mathematics, University of Paderborn, D-33102 Paderborn, Germany § Department of Computer Science, University of Cyprus, Nicosia CY-1678, Cyprus Received (received

  19. Parallel adaptive numerical schemes for hyperbolic systems of ...

    E-Print Network [OSTI]

    1910-50-80

    We describe a parallel implementation of the algorithm on the ... methods that use piecewise linear functions as approximations to solutions of evolution equations: ..... execution of a system disk management routine for a fraction of a second.

  20. Automatic Thread-Level Parallelization in the Chombo AMR Library

    E-Print Network [OSTI]

    Christen, Matthias

    2012-01-01

    Automatic Thread-Level Parallelization in the Chombo AMRused target language for an automatic migration of the largemacros a perfect target for automatic ?ne-grained loop-level

  1. Design algorithms for parallel transmission in magnetic resonance imaging

    E-Print Network [OSTI]

    Setsompop, Kawin

    2008-01-01

    The focus of this dissertation is on the algorithm design, implementation, and validation of parallel transmission technology in Magnetic Resonance Imaging (MRI). Novel algorithms are proposed which yield excellent excitation ...

  2. Towards Energy Aware Scheduling for Precedence Constrained Parallel

    E-Print Network [OSTI]

    Towards Energy Aware Scheduling for Precedence Constrained Parallel Tasks: Jong Youl Cho Community Grids Lab, Indian University #12;Outlook · Background;Energy model #12;Cluster model #12;Job model DAG model: T= (J, E) #12;Job

  3. Provably good race detection that runs in parallel

    E-Print Network [OSTI]

    Fineman, Jeremy T

    2005-01-01

    A multithreaded parallel program that is intended to be deterministic may exhibit nondeterminism clue to bugs called determinacy races. A key capability of race detectors is to determine whether one thread executes logically ...

  4. Parallel Lossless Image Compression Using Huffman and Arithmetic Coding

    E-Print Network [OSTI]

    Howard, Paul G.; Vitter, Jeffrey Scott

    1996-01-01

    We show that high-resolution images can be encoded and decoded e ciently in parallel. We present an algorithm based on the hierarchical MLP method, used either with Hu man coding or with a new variant of arithmetic coding ...

  5. Embracing diversity : improving performance for parallel storage systems built with heterogeneous disks

    E-Print Network [OSTI]

    Bruno, Gregory DuVall

    2008-01-01

    Figure I.2: Parallel Storage System Architecture FigureHeterogeneous Parallel Storage Systems . . . . . B. Modeldisks on a multimedia storage system with random data

  6. Combining magnetic and seismic studies to constrain processes in massive stars

    E-Print Network [OSTI]

    Neiner, C; Coste, B; Briquet, M; Mathis, S

    2013-01-01

    The presence of pulsations influences the local parameters at the surface of massive stars and thus it modifies the Zeeman magnetic signatures. Therefore it makes the characterisation of a magnetic field in pulsating stars more difficult and the characterisation of pulsations is thus required for the study of magnetic massive stars. Conversely, the presence of a magnetic field can inhibit differential rotation and mixing in massive stars and thus provides important constraints for seismic modelling based on pulsation studies. As a consequence, it is necessary to combine spectropolarimetric and seismic studies for all massive classical pulsators. Below we show examples of such combined studies and the interplay between physical processes.

  7. Using true concurrency to model execution of parallel programs

    SciTech Connect (OSTI)

    Ben-Asher, Y.; Farchi, E.

    1994-08-01

    Parallel execution of a program R (intuitively regarded as a partial order) is usually modeled by sequentially executing one of the total orders (interleavings) into which it can be embedded. Our work deviates from this serialization principle by using true concurrency to model parallel execution. True concurrency is represented via completions of R to semi total orders, called time diagrams. These orders are characterized via a set of conditions (denoted by Ct), yielding orders of time diagrams which preserve some degree of the intended parallelism in R. Another way to express semi total orders is to use re-writing or derivation rules (denoted by Cx) which for any program R generates a set of semi-total orders. This paper includes a classification of parallel execution into three classes according to three different types of Ct conditions. For each class a suitable Cx is found and a proof of equivalence between the set of all time diagrams satisfying Ct and the set of all terminal Cx derivations of R is devised. This equivalence between time diagram conditions and derivation rules is used to define a novel notion of correctness for parallel programs. This notion is demonstrated by showing that a specific asynchronous program enforces synchronous execution, which always halts, showing that true concurrency can be useful in the context of parallel program verification.

  8. Sort-First, Distributed Memory Parallel Visualization and Rendering

    SciTech Connect (OSTI)

    Bethel, E. Wes; Humphreys, Greg; Paul, Brian; Brederson, J. Dean

    2003-07-15

    While commodity computing and graphics hardware has increased in capacity and dropped in cost, it is still quite difficult to make effective use of such systems for general-purpose parallel visualization and graphics. We describe the results of a recent project that provides a software infrastructure suitable for general-purpose use by parallel visualization and graphics applications. Our work combines and extends two technologies: Chromium, a stream-oriented framework that implements the OpenGL programming interface; and OpenRM Scene Graph, a pipelined-parallel scene graph interface for graphics data management. Using this combination, we implement a sort-first, distributed memory, parallel volume rendering application. We describe the performance characteristics in terms of bandwidth requirements and highlight key algorithmic considerations needed to implement the sort-first system. We characterize system performance using a distributed memory parallel volume rendering application, a nd present performance gains realized by using scene specific knowledge to accelerate rendering through reduced network bandwidth. The contribution of this work is an exploration of general-purpose, sort-first architecture performance characteristics as applied to distributed memory, commodity hardware, along with a description of the algorithmic support needed to realize parallel, sort-first implementations.

  9. LIMB-DARKENED RADIATION-DRIVEN WINDS FROM MASSIVE STARS

    SciTech Connect (OSTI)

    Cure, M.; Cidale, L.

    2012-10-01

    We calculated the influence of the limb-darkened finite-disk correction factor in the theory of radiation-driven winds from massive stars. We solved the one-dimensional m-CAK hydrodynamical equation of rotating radiation-driven winds for all three known solutions, i.e., fast, {Omega}-slow, and {delta}-slow. We found that for the fast solution, the mass-loss rate is increased by a factor of {approx}10%, while the terminal velocity is reduced about 10%, when compared with the solution using a finite-disk correction factor from a uniformly bright star. For the other two slow solutions, the changes are almost negligible. Although we found that the limb darkening has no effects on the wind-momentum-luminosity relationship, it would affect the calculation of synthetic line profiles and the derivation of accurate wind parameters.

  10. Phase transition of holographic entanglement entropy in massive gravity

    E-Print Network [OSTI]

    Zeng, Xiao-Xiong; Li, Li-Fang

    2015-01-01

    The phase structure of holographic entanglement entropy is studied in massive gravity for the quantum systems with finite and infinite volumes, which in the bulk is dual to calculate the minimal surface area for a black hole and black brane respectively. In the entanglement entropy$-$temperature plane, we find for both the black hole and black brane there is a Van der Waals-like phase transition as the case in thermal entropy$-$temperature plane. That is, there is a first order phase transition for the small charge and a second order phase transition at the critical charge. For the first order phase transition, the equal area law is checked and for the second order phase transition, the critical exponent of the heat capacity is obtained. All the results show that the phase structure of holographic entanglement entropy is the same as that of thermal entropy regardless of the volume of the spacetime on the boundary.

  11. Flavor Mixing and CP Violation of Massive Neutrinos

    E-Print Network [OSTI]

    Zhi-zhong Xing

    2004-11-26

    We present an overview of recent progress in the phenomenological study of neutrino masses, lepton flavor mixing and CP violation. We concentrate on the model-independent properties of massive neutrinos, both in vacuum and in matter. Current experimental constraints on the neutrino mass spectrum and the lepton flavor mixing parameters are summarized. The Dirac- and Majorana-like phases of CP violation, which are associated respectively with the long-baseline neutrino oscillations and the neutrinoless double beta decay, are discussed in detail. The seesaw mechanism, the leptogenesis scenario and the strategies to construct lepton mass matrices are briefly described. The features of flavor mixing between one sterile neutrino and three active neutrinos are also explored.

  12. Nonlinear stability of cosmological solutions in massive gravity

    SciTech Connect (OSTI)

    Felice, Antonio De [ThEP's CRL, NEP, The Institute for Fundamental Study, Naresuan University, Phitsanulok 65000 (Thailand); Gümrükçüo?lu, A. Emir; Lin, Chunshan; Mukohyama, Shinji, E-mail: antoniod@nu.ac.th, E-mail: emir.gumrukcuoglu@ipmu.jp, E-mail: chunshan.lin@ipmu.jp, E-mail: shinji.mukohyama@ipmu.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2013-05-01

    We investigate nonlinear stability of two classes of cosmological solutions in massive gravity: isotropic Friedmann-Lemaître-Robertson-Walker (FLRW) solutions and anisotropic FLRW solutions. For this purpose we construct the linear cosmological perturbation theory around axisymmetric Bianchi type-I backgrounds. We then expand the background around the two classes of solutions, which are fixed points of the background evolution equation, and analyze linear perturbations on top of it. This provides a consistent truncation of nonlinear perturbations around these fixed point solutions and allows us to analyze nonlinear stability in a simple way. In particular, it is shown that isotropic FLRW solutions exhibit nonlinear ghost instability. On the other hand, anisotropic FLRW solutions are shown to be ghost-free for a range of parameters and initial conditions.

  13. Holographic Dual to Conical Defects: I. Moving Massive Particle

    E-Print Network [OSTI]

    D. S. Ageev; I. Ya. Aref'eva; M. D. Tikhanovskaya

    2015-12-10

    We study correlation functions of scalar operators on the boundary of the AdS3 space deformed by moving massive particles in the context of the AdS/CFT duality. To calculate two-point correlation functions we use the geodesic approximation and the renormalized image method. We compare results of the renormalized image method with direct calculations using tracing of winding geodesics around the cone singularities, and show on examples that they are equivalent. We demonstrate that in the geodesic approximation the correlators exhibit a zone structure. This structure essentially depends on the mass and velocity of the particle. The heavy mass particle destroys the original causal structure of the AdS3 boundary, that leads to a rich zone structure.

  14. Nanowire growth by an electron beam induced massive phase transformation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sood, Shantanu [State Univ., of New York, Stony Brook, NY (United States); Kisslinger, Kim [Brookhaven National Lab. (BNL), Upton, NY (United States); Gouma, Perena [State Univ., of New York, Stony Brook, NY (United States)

    2014-12-01

    Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stable growth mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.

  15. Pair Instability Supernovae of Very Massive Population III Stars

    E-Print Network [OSTI]

    Chen, Ke-Jung; Woosley, Stan; Almgren, Ann; Whalen, Daniel

    2014-01-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 Msun die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core collapse, to capture any dynamical instabilities that may be seeded by collapse and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning ari...

  16. Observing the onset of outflow collimation in a massive protostar

    E-Print Network [OSTI]

    Carrasco-González, C; Cantó, J; Curiel, S; Surcis, G; Vlemmings, W H T; van Langevelde, H J; Goddi, C; Anglada, G; Kim, S -W; Kim, J -S; Gómez, J F

    2015-01-01

    The current paradigm of star formation through accretion disks, and magnetohydrodynamically driven gas ejections, predicts the development of collimated outflows, rather than expansion without any preferential direction. We present radio continuum observations of the massive protostar W75N(B)-VLA 2, showing that it is a thermal, collimated ionized wind and that it has evolved in 18 years from a compact source into an elongated one. This is consistent with the evolution of the associated expanding water-vapor maser shell, which changed from a nearly circular morphology, tracing an almost isotropic outflow, to an elliptical one outlining collimated motions. We model this behavior in terms of an episodic, short-lived, originally isotropic, ionized wind whose morphology evolves as it moves within a toroidal density stratification.

  17. Galileons coupled to massive gravity: general analysis and cosmological solutions

    SciTech Connect (OSTI)

    Goon, Garrett; Trodden, Mark; Gümrükçüo?lu, A. Emir; Hinterbichler, Kurt; Mukohyama, Shinji E-mail: Emir.Gumrukcuoglu@nottingham.ac.uk E-mail: shinji.mukohyama@ipmu.jp

    2014-08-01

    We further develop the framework for coupling galileons and Dirac-Born-Infeld (DBI) scalar fields to a massive graviton while retaining both the non-linear symmetries of the scalars and ghost-freedom of the theory. The general construction is recast in terms of vielbeins which simplifies calculations and allows for compact expressions. Expressions for the general form of the action are derived, with special emphasis on those models which descend from maximally symmetric spaces. We demonstrate the existence of maximally symmetric solutions to the fully non-linear theory and analyze their spectrum of quadratic fluctuations. Finally, we consider self-accelerating cosmological solutions and study their perturbations, showing that the vector and scalar modes have vanishing kinetic terms.

  18. Nanowire growth by an electron beam induced massive phase transformation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sood, Shantanu; Kisslinger, Kim; Gouma, Perena

    2014-11-15

    Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stablemore »growth mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.« less

  19. Nanowire growth by an electron beam induced massive phase transformation

    SciTech Connect (OSTI)

    Sood, Shantanu; Kisslinger, Kim; Gouma, Perena

    2014-11-15

    Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stable growth mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.

  20. X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

    SciTech Connect (OSTI)

    Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie; Owocki, Stan; Cohen, David; Ud-Doula, Asif; Wade, Gregg A.

    2014-11-01

    Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ?60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens for the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres.