A new material particle dynamical domain decomposition method MPD3 has been developed. The method is suitable for a large scale parallel molecular dynamic simulation on a heterogeneous computing net. Performance of the MPD3 algorithm is tested in various computing environments, such as PC clusters, super computer clusters, and Grid. It is shown that the MPD3 algorithm is highly adaptivefor both computer clusters and Grid computing environments, even ifotherprograms are running on the same computer environment.
1] We developed a real-time numerical simulator for the solar wind --space --magnetosphere -ionosphere coupling system, adopting the three-dimensional (3-D) magnetohydrodynamic (MHD) simulation code developed by Tanaka. By using the real-time solar wind data, which is available from the ACE spacecraft every minute, as the upstream boundary conditions for density, temperature, flow speed, and interplanetary magnetic field, our MHD simulation system can numerically reproduce the global response of the magnetosphere and ionosphere at the same time as in the real world. We achieved realtime 3-D simulations of the solar wind --magnetosphere --ionosphere coupling system with a 44 Â 56 Â 60 mesh size by adapting high-performance FORTRAN language with eight CPUs on a supercomputer system located at the National Institute of Information and Communications Technology (NICT). Simulated plasma temperature and density in geostationary orbit were also plotted as an index to predict satellite charging. In addition, we present real-time virtual AE indices obtained from simulation results that directly compare with geomagnetic field activities as well as real-time plasma temperature and density in geostationary orbit. Our real-time MHD simulator now runs routinely on NICT's supercomputer system. We will present a detailed configuration of the real-time simulator system in this paper. Some examples are presented from system output to show how solar wind variations result in geomagnetic disturbances.Citation: Den, M., et al. (2006), Real-time Earth magnetosphere simulator with three-dimensional magnetohydrodynamic code, Space Weather, 4, S06004,
We succeeded in getting 14.9 TFLOPS performance when running a plasma simulation code IMPACT-3D parallelized with High Performance Fortran on 512 nodes of the Earth Simulator. The theoretical peak performance of the 512 nodes is 32 TFLOPS, which means 45% of the peak performance was obtained with HPF. IMPACT-3D is an implosion analysis code using TVD scheme, which performs three-dimensional compressible and inviscid Eulerian fluid computation with the explicit 5-point stencil scheme for spatial differentiation and the fractional time step for time integration. The mesh size is 2048x2048x4096, and the third dimension was distributed for the parallelization. The HPF system used in the evaluation is HPF/ES, developed for the Earth Simulator by enhancing NEC HPF/SX V2 mainly in communication scalability. Shift communications were manually tuned to get best performance by using HPF/JA extensions, which was designed to give the users more control over sophisticated parallelization and communication optimizations.
SUMMARYThis paper presents a set of extensions on High Performance Fortran (HPF) to make it more usable for parallelizing real-world production codes. HPF has been effective for programs that a compiler can automatically optimize efficiently. However, once the compiler cannot, there have been no ways for the users to explicitly parallelize or optimize their programs. In order to resolve the situation, we have developed a set of HPF extensions (HPF/JA) to give the users more control over sophisticated parallelization and communication optimizations. They include parallelization of loops with complicated reductions, asynchronous communication, user-controllable shadow, and communication pattern reuse for irregular remote data accesses. Preliminary experiments have proved that the extensions are effective at increasing HPF's usability.
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