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Title: Ensemble Sampling vs. Time Sampling in Molecular Dynamics Simulations of Thermal Conductivity

Abstract

In this report we compare time sampling and ensemble averaging as two different methods available for phase space sampling. For the comparison, we calculate thermal conductivities of solid argon and silicon structures, using equilibrium molecular dynamics. We introduce two different schemes for the ensemble averaging approach, and show that both can reduce the total simulation time as compared to time averaging. It is also found that velocity rescaling is an efficient mechanism for phase space exploration. Although our methodology is tested using classical molecular dynamics, the ensemble generation approaches may find their greatest utility in computationally expensive simulations such as first principles molecular dynamics. For such simulations, where each time step is costly, time sampling can require long simulation times because each time step must be evaluated sequentially and therefore phase space averaging is achieved through sequential operations. On the other hand, with ensemble averaging, phase space sampling can be achieved through parallel operations, since each ensemble is independent. For this reason, particularly when using massively parallel architectures, ensemble sampling can result in much shorter simulation times and exhibits similar overall computational effort.

Authors:
 [1];  [2];  [1]
  1. Georgia Inst. of Technology, Atlanta, GA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1185896
Alternate Identifier(s):
OSTI ID: 1286997
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 04; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Gordiz, Kiarash, Singh, David J., and Henry, Asegun. Ensemble Sampling vs. Time Sampling in Molecular Dynamics Simulations of Thermal Conductivity. United States: N. p., 2015. Web. doi:10.1063/1.4906957.
Gordiz, Kiarash, Singh, David J., & Henry, Asegun. Ensemble Sampling vs. Time Sampling in Molecular Dynamics Simulations of Thermal Conductivity. United States. doi:10.1063/1.4906957.
Gordiz, Kiarash, Singh, David J., and Henry, Asegun. Thu . "Ensemble Sampling vs. Time Sampling in Molecular Dynamics Simulations of Thermal Conductivity". United States. doi:10.1063/1.4906957. https://www.osti.gov/servlets/purl/1185896.
@article{osti_1185896,
title = {Ensemble Sampling vs. Time Sampling in Molecular Dynamics Simulations of Thermal Conductivity},
author = {Gordiz, Kiarash and Singh, David J. and Henry, Asegun},
abstractNote = {In this report we compare time sampling and ensemble averaging as two different methods available for phase space sampling. For the comparison, we calculate thermal conductivities of solid argon and silicon structures, using equilibrium molecular dynamics. We introduce two different schemes for the ensemble averaging approach, and show that both can reduce the total simulation time as compared to time averaging. It is also found that velocity rescaling is an efficient mechanism for phase space exploration. Although our methodology is tested using classical molecular dynamics, the ensemble generation approaches may find their greatest utility in computationally expensive simulations such as first principles molecular dynamics. For such simulations, where each time step is costly, time sampling can require long simulation times because each time step must be evaluated sequentially and therefore phase space averaging is achieved through sequential operations. On the other hand, with ensemble averaging, phase space sampling can be achieved through parallel operations, since each ensemble is independent. For this reason, particularly when using massively parallel architectures, ensemble sampling can result in much shorter simulation times and exhibits similar overall computational effort.},
doi = {10.1063/1.4906957},
journal = {Journal of Applied Physics},
number = 04,
volume = 117,
place = {United States},
year = {Thu Jan 29 00:00:00 EST 2015},
month = {Thu Jan 29 00:00:00 EST 2015}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 10 works
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