Acceleration of Boltzmann Equation for Core-Collapse Supernova Simulations on PEZY-SC Processors

Abstract

Performing large scale numerical simulations is essential to understand the explosion mechanism of core-collapse supernovae. It is mandatory to solve a multi-physics system described by coupled equations of hydrodynamics and neutrino-radiation transfer in multi-dimensions. Since the neutrino transfer is in principle governed by the Boltzmann equation in six-dimensional coordinates, numerical simulations require large computational resources. In this work, we focus on the acceleration of the Boltzmann equation by exploiting the PEZY-SC processors. The PEZY-SC processor possesses many-core MIMD cores on each chip, and works as an accelerator device similarly to GPUs. We examine two simulation codes for the neutrino transport in the supernova simulations. One is a radiation-hydrodynamics code under the spherical symmetry. The second is a 6D Boltzmann equation solver applied to two-dimensional space. We examine the bottlenecks of these codes and offload them to the PEZY-SC devices. The performance is measured on the Suiren Blue and Suiren2 systems at KEK.