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Onodera, Naoyuki; Idomura, Yasuhiro; Kawamura, Takuma; Uesawa, Shinichiro; Yamashita, Susumu; Yoshida, Hiroyuki
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 6 Pages, 2019/05
A dry method is one of practical methods for decommissioning the TEPCO's Fukushima Daiichi Nuclear Power Station. Japan Atomic Energy Agency (JAEA) has been evaluating the air cooling performance by using the JUPITER code. However, the JUPITER code requires a large computational cost to capture debris' structures. To accelerate such CFD analyses, we use the CityLBM code, which is based on the lattice Boltzmann method (LBM) and is highly optimized for GPUs. The CityLBM code is validated against free convective heat transfer experiments at JAEA, and the similar accuracy as the JUPITER code is confirmed regarding the prediction capability of heat transfer and the resulting temperature distributions. It is also shown that the elapse time of a CityLBM simulation on GPUs is reduced to 1/6 compared with that of the corresponding JUPITER simulation on CPUs with the same number of GPUs and CPUs. The results show that the LBM is promising for accelerating thermal convective simulations.
Maeyama, Shinya*; Watanabe, Tomohiko*; Idomura, Yasuhiro; Nakata, Motoki*; Nunami, Masanori*
Computer Physics Communications, 235, p.9 - 15, 2019/02
Times Cited Count：5 Percentile：46.27(Computer Science, Interdisciplinary Applications)We have implemented the Sugama collision operator in the gyrokinetic Vlasov simulation code, GKV, with an implicit time-integration scheme. The new method is versatile and independent of the details of the linearized collision operator, by means of an operator splitting, an implicit time integrator, and an iterative Krylov subspace solver. Numerical tests demonstrate stable computation over the time step size restricted by the collision term. An efficient implementation for parallel computation on distributed memory systems is realized by using the data transpose communication, which makes the iterative solver free from inter-node communications during iteration. Consequently, the present approach achieves enhancement of computational efficiency and reduction of computational time to solution simultaneously, and significantly accelerates the total performance of the application.
Yoshida, Hiroyuki; Ose, Yasuo*; Kureta, Masatoshi*; Nagayoshi, Takuji*; Takase, Kazuyuki; Akimoto, Hajime
Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(2), p.106 - 114, 2005/06
no abstracts in English
Shinohara, Kazunori; Okuda, Hiroshi*; Ito, Satoshi*; Nakajima, Norihiro; Ida, Masato
Keisan Kogaku Koenkai Rombunshu, 10(2), p.629 - 632, 2005/05
To obtain optimal designed shape effectively, a parallel computing method of determining Armijo's line-search step size of the adjoint variable method is proposed. 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 shaped surface under a constant volume condition are formulated. To solve the equations effectively by the steepest descent method, the parallel algorithm that finds the Armijo's line-search step size is implemented by using ITBL (the grid system of Japan's shared super computers attached to the network). Using this parallel method, the calculation cost can be reduced.
Yamada, Susumu; Imamura, Toshiyuki*; Machida, Masahiko; Arakawa, Chuichi*
Nihon Keisan Kogakkai Rombunshu, 7, p.243 - 252, 2005/05
no abstracts in English
Nakajima, Norihiro; Ono, Nobuaki*; Suzuki, Yoshio*; Kureta, Masatoshi*
Denki Gakkai Rombunshi, C, 124(10), p.2197 - 2198, 2004/10
Our research interest is to implement volume rendering on CAVE system at enough frame rate. It can be implemented on CAVE easily using texture mapping but there are some defects; for example frame rate declines when the view point is close to the data and images projected to the screens become big. Thus we try to find another way to implement it on CAVE. Considering that Onyx300 is a parallel computer and there are some algorisms of volume rendering which improve the frame rate, we make the program that draws stereo images through two of the algorisms and by parallel computing, and displays only two images on CAVE. And we confirm that this program works well and draws stereo images at sufficient frame rates.
Yamada, Susumu; Machida, Masahiko; Imamura, Toshiyuki*
Joho Shori Gakkai Rombunshi; Komputeingu Shisutemu (Internet), 45(SIG6(ACS6)), p.161 - 170, 2004/05
no abstracts in English
(
=1-4) by all-electron Dirac-Hartree-Fock calculationsMochizuki, Yuji*; Tatewaki, Hiroshi*
Journal of Chemical Physics, 118(20), p.9201 - 9207, 2003/05
Times Cited Count：6 Percentile：18.14(Chemistry, Physical)no abstracts in English
Shimizu, Futoshi; Kadoyoshi, Tomoko; Kaburaki, Hideo; Yamagishi, Nobuhiro*; Hasegawa, Yukihiro*; Higuchi, Kenji
Keisan Kogaku Koenkai Rombunshu, 8(2), p.801 - 804, 2003/05
no abstracts in English
Shimizu, Futoshi; Kaburaki, Hideo
Ansanburu, (22), p.23 - 29, 2003/04
no abstracts in English
Idomura, Yasuhiro; Adachi, Masaaki*; Gorai, Kazuo; Suzuki, Yoshio; Wang, X.*
Purazuma, Kaku Yugo Gakkai-Shi, 79(2), p.172 - 187, 2003/02
Under the Numerical EXperiment of Tokamak (NEXT) research project, various fluid, particle, and hybrid codes have been developed. These codes require a computational environment which consists of high performance processors, high speed storage system, and high speed parallelized visualization system. In this paper, the performance of the JAERI Origin3800 system is examined from a point of view of these requests. In the performance tests, it is shown that the representative particle and fluid codes operate with 
% of processing efficiency up to 512 processors. A storage area network (SAN) provides high speed parallel data transfer. A parallel visualization system enables order of magnitude faster visualization of a large scale simulation data compared with the previous graphic workstations. Accordingly, an extremely advanced simulation environment is realized on the JAERI Origin3800 system. Recently, development of a storage grid is underway in order to improve a computational environment of remote users. The storage grid is constructed by a combination of SAN and a wavelength division multiplexer (WDM). The preliminary tests show that compared with the existing data transfer methods, it enables dramatically high speed data transfer 
Gbps over a wide area network.
Shimizu, Futoshi; Kimizuka, Hajime*; Kaburaki, Hideo; Arakawa, Chuichi*
Keisan Kogaku Koenkai Rombunshu, 7(1), p.163 - 166, 2002/05
no abstracts in English
Shimizu, Futoshi; Kimizuka, Hajime*; Kaburaki, Hideo; Arakawa, Chuichi*
Nihon Keisan Kogakkai Rombunshu, 4, p.225 - 230, 2002/04
no abstracts in English
Ishida, Hisashi
Proceedings of the International Conference on Bioinformatics 2002 (CD-ROM), 6 Pages, 2002/02
no abstracts in English
Watanabe, Tadashi; Kono, Koji*; Ohashi, H.*
Application of High-Performance Computing in Engineering VII, p.115 - 124, 2002/00
no abstracts in English
Hosokawa, Masanari*; Takizuka, Tomonori
JAERI-Data/Code 2001-026, 19 Pages, 2001/10
JAERI-Data-Code-2001-026.pdf:1.66MB
no abstracts in English
Yamada, Susumu; Shimizu, Futoshi; Imai, Ryuta*; Kimizuka, Hajime*; Kaji, Yoshiyuki; Kaburaki, Hideo
Keisan Kogaku Koenkai Rombunshu, 6(1), p.233 - 236, 2001/05
no abstracts in English
Hagiwara, Ichiro*; Li, W.*; Nakata, Susumu*; Yamada, Susumu
Keisan Kogaku Koenkai Rombunshu, 61(1), p.205 - 208, 2001/05
no abstracts in English
Muramatsu, Kazuhiro; Imamura, Toshiyuki; Kitabata, Hideyuki; Kaneko, Isamu; Takemiya, Hiroshi*; Hasegawa, Yukihiro*; Yamagishi, Nobuhiro*; Hirayama, Toshio
Keisan Kogaku Koenkai Rombunshu, 6(1), p.241 - 244, 2001/05
no abstracts in English
Nuclear Code Evaluation Special Committee of Nuclear Code Research Committee
JAERI-Conf 2000-018, 342 Pages, 2001/01
JAERI-Conf-2000-018.pdf:19.4MB
no abstracts in English
