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UID:submissions.supercomputing.org_SC25_sess177_pap676@linklings.com
SUMMARY:The First Star-by-Star $N$-body/Hydrodynamics Simulation of Our Ga
 laxy Coupling with a Surrogate Model
DESCRIPTION:Keiya Hirashima (RIKEN Center for Interdisciplinary Theoretica
 l and Mathematical Sciences); Michiko Fujii (The University of Tokyo); Tak
 ayuki Saitoh (Kobe University, Japan); Naoto Harada (The University of Tok
 yo); Kentaro Nomura (Preferred Networks Inc.); Kohji Yoshikawa (Tsukuba Un
 iversity); Yutaka Hirai (Koeki University); Tetsuro Asano (Universitat de 
 Barcelona); Kana Moriwaki (The University of Tokyo); Masaki Iwasawa (Matsu
 e College); Takashi Okamoto (Hokkaido University, Japan); and Junichiro Ma
 kino (Kobe University, Japan; Preferred Networks Inc.)\n\nA major goal of 
 computational astrophysics is to simulate the Milky Way galaxy with suffic
 ient resolution, down to individual stars. However, the scaling fails due 
 to some small-scale, short-timescale phenomena, such as supernova explosio
 ns. We have developed a novel integration scheme of $N$-body/hydrodynamics
  simulations working with machine learning. This approach bypasses the sho
 rt timesteps caused by supernova explosions using a surrogate model, there
 by improving scalability. With this method, we reached 300 billion particl
 es using 148,900 nodes, equivalent to 7,147,200 CPU cores, breaking throug
 h the billion-particle barrier currently faced by state-of-the-art simulat
 ions. This resolution allows us to perform the first star-by-star galaxy s
 imulation, which resolves individual stars in the Milky Way galaxy. The pe
 rformance scales over $10^4$ CPU cores, an upper limit in the current stat
 e-of-the-art simulations using both A64FX and X86-64 processors and NVIDIA
  CUDA GPUs.\n\nTag: Applications, Gordon Bell Climate Finalist\n\nRecordin
 g: Livestreamed, Recorded\n\nRegistration Category: Technical Program Reg 
 Pass\n\nSession Chair: Shelby Lockhart (Advanced Micro Devices, Inc. (AMD)
 )\n\n
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