24.77 Pflops on a Gravitational Tree-Code to Simulate the Milky Way Galaxy with 18600 GPUs

TL;DR

This paper reports a groundbreaking large-scale simulation of the Milky Way galaxy using 51 billion particles on supercomputers, achieving over 24 petaflops in performance and providing detailed insights into galactic evolution.

Contribution

It introduces a highly scalable gravitational tree-code that simulates galaxy evolution with unprecedented particle count and performance on supercomputers.

Findings

Simulated Milky Way evolution for 6 billion years with 51 billion particles.

Achieved 24.77 Pflops sustained performance on 18600 GPUs.

Demonstrated high scalability and efficiency on supercomputing platforms.

Abstract

We have simulated, for the first time, the long term evolution of the Milky Way Galaxy using 51 billion particles on the Swiss Piz Daint supercomputer with our $N$-body gravitational tree-code Bonsai. Herein, we describe the scientific motivation and numerical algorithms. The Milky Way model was simulated for 6 billion years, during which the bar structure and spiral arms were fully formed. This improves upon previous simulations by using 1000 times more particles, and provides a wealth of new data that can be directly compared with observations. We also report the scalability on both the Swiss Piz Daint and the US ORNL Titan. On Piz Daint the parallel efficiency of Bonsai was above 95%. The highest performance was achieved with a 242 billion particle Milky Way model using 18600 GPUs on Titan, thereby reaching a sustained GPU and application performance of 33.49 Pflops and 24.77 Pflops respectively.