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Togashi, Tomoaki*; Shimizu, Noritaka*; Utsuno, Yutaka; Abe, Takashi*; Otsuka, Takaharu*
Procedia Computer Science, 29, p.1711 - 1721, 2014/06
Times Cited Count：1 Percentile：29.91(Computer Science, Theory & Methods)Computing Hamiltonian matrix elements between non-orthogonal Slater determinants is often needed for nuclear-structure calculations, and it is the most time-consuming part in many cases. In this paper, we demonstrate that utilizing GPGPU is an efficient way to perform this calculation. In our earlier study, we showed that the calculation of the Hamiltonian matrix elements between non-orthogonal Slater determinants is transformed into the multiplication of matrices. This method is useful for the GPGPU calculation because of less memory access compared to the usual method. We implement the GPGPU computation in the Monte Carlo shell-model code and measure the elapsed time. The resulting performance is over 0.6 TFLOPS for the GPU that has 1.13 TFLOPS peak performance. This method is particularly effective for large-scale calculations because higher efficiency is obtained for the calculation of larger model spaces.
Kushida, Noriyuki; Fujibayashi, Kenichi; Takemiya, Hiroshi
Procedia Computer Science, 4, p.898 - 907, 2011/00
Times Cited Count：0 Percentile：0(Computer Science, Theory & Methods)A high speed eigenvalue solver that is an essential part of a plasma stability analysis system for fusion reactors on a Cell cluster system is described. For the purpose of continuous operation of fusion reactors, we must evaluate the state of plasma within the characteristic confinement time of the plasma density and temperature in fusion reactors. In order to resolve the problem, we introduced a Cell cluster system and developed a novel eigenvalue solver, which usually consumes most of the plasma evaluation time, to achieve high performance of the system. As a result, we succeeded in obtaining our target performance: we were able to solve a block tri-diagonal Hermitian matrix containing 1024 diagonal blocks, where the size of each block was 128
128, within a second. Therefore, we have found a suitable candidate for achieving a satisfactory monitoring system.
Yabana, Kazuhiro*; Shinohara, Yasushi*; Otobe, Tomohito; Iwata, Junichi*; Bertsch, G. F.*
Procedia Computer Science, 4, p.852 - 859, 2011/00
Times Cited Count：2 Percentile：60.79(Computer Science, Theory & Methods)We report a first-principle computational method to describe many-electron dynamics in crystalline solid. The method is based on the time-dependent density functional theory, solving time-dependent Kohn-Sham equation in real-time and real-space. The calculation is efficiently parallelized by distributing computations of different 
-point among processors. To illustrate usefulness of the method and efficiency of the parallel computation, we show calculations of electron dynamics in bulk Si induced by intense and ultrafast laser pulse.
