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Idomura, Yasuhiro; Onodera, Naoyuki; Yamada, Susumu; Yamashita, Susumu; Ina, Takuya*; Imamura, Toshiyuki*
Supa Kompyuteingu Nyusu, 22(5), p.18 - 29, 2020/09
A communication avoiding multigrid preconditioned conjugate gradient method (CAMGCG) is applied to the pressure Poisson equation in a multiphase CFD code JUPITER, and its computational performance and convergence property are compared against the conventional Krylov methods. The CAMGCG solver has robust convergence properties regardless of the problem size, and shows both communication reduction and convergence improvement, leading to higher performance gain than CA Krylov solvers, which achieve only the former. The CAMGCG solver is applied to extreme scale multiphase CFD simulations with 90 billion DOFs, and its performance is compared against the preconditioned CG solver. In this benchmark, the number of iterations is reduced to 
, and 
speedup is achieved with keeping excellent strong scaling up to 8,000 nodes on the Oakforest-PACS.
Shinohara, Kazunori; Okuda, Hiroshi*; Nakajima, Norihiro; Ida, Masato
Nihon Kikai Gakkai Dai-18-Kai Keisan Rikigaku Koenkai Koen Rombunshu, p.561 - 562, 2005/11
To obtain optimal designed shape effectively, the 3D shape optimization system of adjoint variable method is developed. The adjoint valiable method is based on the Lagrange multiplier method (a conditional variational principle), and consists of the state equation, the adjoint equation and the sensitivity equation. The equations for decreasing the fluid drag of surface under a constant volume condition are formulated. To solve the equations effectively, the compressed-matrix storage mode and the data passing system are implemented by using HPCMW. By using the 3D shape optimization system, the surface force of shape can be reduced about 24%.
Muramatsu, Kazuhiro; Otani, Takayuki; Kitabata, Hideyuki; Matsumoto, Hideki*; Takei, Toshifumi*; Doi, Shun*
Proceedings of 4th International Conference on Supercomputing in Nuclear Applications (SNA 2000) (CD-ROM), 10 Pages, 2000/09
no abstracts in English
Muramatsu, Kazuhiro; Matsumoto, Hideki*; Takei, Toshifumi*; Doi, Shun*
Joho Shori Gakkai Dai-58-Kai (Heisei-11-Nen Zenki) Zenkoku Taikai Kouen Ronbunshu, p.1_405 - 1_406, 1999/00
no abstracts in English
Muramatsu, Kazuhiro; Kitabata, Hideyuki*; Matsumoto, Hideki*; Takei, Toshifumi*; Doi, Shun*
Dai-8-Kai NEC, HPC Kenkyukai Rombunshu, p.45 - 51, 1998/00
no abstracts in English
Doi, Shun*; Matsumoto, Hideki*; Takei, Toshifumi*; Aikawa, Hiroshi
Keisan Kogaku Koenkai Rombunshu, 2(1), p.109 - 112, 1997/05
no abstracts in English
; Onishi, Ryoichi*; ; Guo, Z.*
Keisan Kogaku Koenkai Rombunshu, 2(1), p.121 - 124, 1997/05
no abstracts in English
; Nakamura, Hideo; ; ; Maekawa, Hiroshi
Eighth Int. Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-8), 3, p.1276 - 1283, 1997/00
no abstracts in English
Muramatsu, Kazuhiro; Takei, Toshifumi*; Matsumoto, H.*; Doi, Shun*
Joho Shori Gakkai Kenkyu Hokoku, 96(50), p.27 - 32, 1996/05
no abstracts in English
; ; ; ; Yokokawa, Mitsuo;
JAERI-Data/Code 94-021, 119 Pages, 1995/01
JAERI-Data-Code-94-021.pdf:3.08MB
no abstracts in English
Kunugi, Tomoaki; Yokokawa, Mitsuo;
JAERI-M 88-119, 80 Pages, 1988/07
no abstracts in English
;
JAERI-M 82-124, 41 Pages, 1982/09
no abstracts in English
Onodera, Naoyuki; Idomura, Yasuhiro; Ali, Y.*; Yamashita, Susumu; Ina, Takuya*; Imamura, Toshiyuki*
no journal, ,
Transient heat flow analysis of nuclear reactors is very important from the view point of efficient design and safety. We have developed the stencil-based CFD code JUPITER for simulating three-dimensional multiphase flows. We extended the JUPITER with GPU-accelerated Poisson solvers based on the P-CG and P-CBCG methods. All main kernels were implemented using CUDA, and the GPU kernel function is well tuned to achieve high performance on the latest Volta-core GPUs. The developed solvers showed good strong scaling up to 2,048 GPUs/CPUs on the Summit (NVIDIA TESLA V100), the ABCI (NVIDIA TESLA V100), the Oakforest-PACS (Intel Knights Landing). Finally, the performance gain from the Oakforest-PACS ranges from 1.2 
1.6x on the Summit and 1.4 1.7x on the ABCI, respectively.
Idomura, Yasuhiro
no journal, ,
Thanks to new technologies such as KNL and MCDRAM, Oakforest-PACS (OfP) achieved significantly high computing power and memory bandwidths against the conventional multi-core platforms, and played an important role as a prototype of exascale supercomputers. We developed extreme scale nuclear CFD simulations on OfP, where an important issue was to resolve communication bottlenecks revealed by accelerated computation. This issue was resolved by developing communication-avoiding (CA) matrix solvers based on CA Krylov subspace methods and CA multigrid methods, and high performance CFD simulations were enabled by using the full system size on OfP. In this talk, we review CA matrix solvers developed for the five dimensional plasma simulation code GT5D and the three dimensional multi-phase multi-component thermal-hydraulic code JUPITER.
Ono, Ayako
no journal, ,
The research committee for mechanistic evaluation of critical heat flux for nuclear reactors reviewed many studies and extracted issues to be considered to establish the evaluation method of critical heat flux based on the mechanism. In this presentation, the outcomes of the activities of the research committee and the future perspective of CHF study will be reported.