A ghost cell expansion method for reducing communications in solving PDE problems
In solving Partial Differential Equations, such as the Barotropic equations in ocean models, on Distributed Memory Computers, finite difference methods are commonly used. Most often, processor subdomain boundaries must be updated at each time step. This boundary update process involves many messages of small sizes, therefore large communication overhead. Here we propose a new approach which expands the ghost cell layers and thus updates boundaries much less frequently ---reducing total message volume and grouping small messages into bigger ones. Together with a technique for eliminating diagonal communications, the method speedup communication substantially, up to 170%. We explain the method and implementation in details, provide systematic timing results and performance analysis on Cray T3E and IBM SP.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of Biological and Environmental Research (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 783770
- Report Number(s):
- LBNL-47929; R&D Project: K11501; TRN: AH200128%%204
- Resource Relation:
- Conference: Supercomputing 2001 (SC2001), Denver, CO (US), 11/10/2001--11/16/2001; Other Information: PBD: 1 May 2001
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
DATA TRANSMISSION
SUPERCOMPUTERS
FINITE DIFFERENCE METHOD
IMPLEMENTATION
PARTIAL DIFFERENTIAL EQUATIONS
PERFORMANCE
OCEANIC CIRCULATION
GENERAL CIRCULATION MODELS
HIGH PERFORMANCE COMPUTING PARTICIAL DIFFERENTIAL EQUATION