The Large Scale Parallel Simulation Performed on the K computer was Awarded the ACM Gordon Bell Prize

A research group of University of Tsukuba, RIKEN, and Tokyo Institute of Technology announced that the ACM Gordon Bell Prize (*1) was awarded to that group.

The award was for the large scale parallel simulation using the "K computer" (*2) at SC12, the International Conference for High Performance Computing, Networking, Storage and Analysis held in Salt Lake City, on November 15 (US Pacific Standard Time). The group performed extremely large simulations with an unprecedentedly high level of efficiency. The group performed extremely large simulations with an unprecedentedly high level of efficiency.

The target of the award-winning simulation, presented at SC12, was the gravitational evolution of dark matter (*3) in the early Universe. The number of dark matter particles simulated was two trillions, which is the world's largest dark matter simulation at present. The execution performance (*4) was 5.67 Pflops on the 98% resources of the K computer system.

This year, the Gordon Bell Prize was awarded singly to the Tsukuba group. A USA group achieved a 14 Pflops execution performance on Sequoia of LLNL for a similar dark matter simulation. Although the peak performance of Sequoia is twice that of K computer, the calculation speed achieved by the Tsukuba group is 2.4 times faster than that by the USA group. This is because the numerical algorithm of the Tsukuba group is more advanced than that of the USA group.

The research group has been studying continually the fine structures of dark matter. By combining this software with the SPH (smoothed particle hydrodynamics) algorithm for compressive fluids, the group is addressing early scientific achievements such as star formation and galaxy formation simulated on the K computer.

Glossary and notes

1. ACM Gordon Bell prize

The ACM Gordon Bell Prize, sponsored by the Association of Computing Machinery, is awarded to promote advancements in parallel computing technology, and is presented every November at the International Conference for High Performance Computing, Networking, Storage and Analysis (SC, Supercomputing Conference) to the papers that show the most outstanding results in hardware and application development.

2. K computer

The K computer, jointly developed by RIKEN and Fujitsu, is part of the High-Performance Computing Infrastructure (HPCI) initiative led by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT). This newly developed supercomputer commenced full operation at the end of September 2012. The "K computer" is the registered trademark of RIKEN. "K" comes from the Japanese Kanji letter "Kei" which means ten peta or 10 to the 16th power. In its original sense, "Kei" expresses a large gateway, and it is hoped that the system will be a new gateway to computational science.

3. Dark matter

It is the matter to interact via the gravity only. The nature of dark matter particle is still unknown. The initial primordial density fluctuations of dark matter grow via the gravity and form dark matter structures with various sizes everywhere. Then, the baryonic matter condenses in the gravitational potential of these dark matter structures, and forms first stars and galaxies. This is the cold dark matter theory, which is widely accepted as the standard theory of the formation and evolution of the Universe.

4. Execution performance

In contrast to theoretical performance, this is the computational performance obtained in running a given program, and acts as a practical measure of a computer’s performance.

5. Massively parallel code

An application program that can run efficiently on a massively parallel computer.

Paper awarded the Gordon Bell Prize

Tomoaki Ishiyama, Keigo Nitadori, and Junichiro Makino, 2012, "4.45 Pflops astrophysical N-body simulation on K computer: the gravitational trillion-body problem", in Proceedings of the International Conference on High Performance Computing, Networking, Storage and Analysis (SC '12), IEEE Computer Society Press, Los Alamitos, CA, USA, Article 5