MD simulation of hundred-billion-metal-atom cascade collision on Sunway Taihulight

GS Chu and Y Li and RC Zhao and S Ren and W Yang and XF He and CJ Hu and J Wang, COMPUTER PHYSICS COMMUNICATIONS, 269, 108128 (2021).

DOI: 10.1016/j.cpc.2021.108128

Radiation damage to the steel material of reactor pressure vessels is a major threat to the nuclear reactor safety. It is caused by the metal atom cascade collision, initialized when the atoms are struck by a high- energy neutron. The paper presents MISA-MD, a new implementation of molecular dynamics, to simulate such cascade collision with EAM potential. MISA-MD realizes (1) a hash-based data structure to efficiently store an atom and find its neighbors, and (2) several acceleration and optimization strategies based on SW26010 processor of Sunway Taihulight supercomputer, including an efficient potential table storage and interpolation method, a coloring method to avoid write conflicts, and double-buffer and data reuse strategies. The experimental results demonstrated that MISA-MD has good accuracy and scalability, and obtains a parallel efficiency of over 79% in an 655-billion-atom system. Compared with a state-of -the-art MD program LAMMPS, MISA-MD requires less memory usage and achieves better computational performance. Program summary Program Title: MISA-MD CPC Library link to program files: https://doi .org/10.17632/x2bmx6whcd.1 Code Ocean capsule: https://doi.org/10.24433/CO.4041607.v1 Licensing provisions: BSD 3-clause Programming language: C and C++ Nature of problem: Molecular dynamics (MD) is a significant method to simulate the cascade collision progress of the key material in nuclear reactors. However, there are many difficulties for existing MD programs to perform large scale cascade collision simulations. Thus, it is especially essential to develop a new MD software to extend cascade collision simulations to larger spatial scale and longer temporal scale. Solution method: To achieve accuracy and effective MD cascade collision simulation, the EAM potential is selected to calculate interactional force between atoms in the simulation system. To extend MD simulation to larger scale, we proposed a hash-based data structure/algorithm to efficiently store an atom and find its neighbors, and several acceleration and optimization strategies based on SW26010 processor of Sunway Taihulight supercomputer. (C) 2021 Elsevier B.V. All rights reserved.

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