Accelerating quantum many-body configuration interaction with directives

TL;DR

This paper discusses optimizing the Many-Fermion Dynamics-nuclear (MFDn) code for nuclear structure calculations by leveraging GPU accelerators using OpenACC, addressing key implementation challenges and comparing GPU programming models.

Contribution

It introduces a GPU implementation of MFDn using OpenACC, highlighting challenges and comparing OpenMP and OpenACC support on different GPU architectures.

Findings

OpenACC enables GPU acceleration of MFDn.

Challenges in GPU implementation include data management and parallelization.

OpenMP and OpenACC support varies across AMD and NVIDIA GPUs.

Abstract

Many-Fermion Dynamics-nuclear, or MFDn, is a configuration interaction (CI) code for nuclear structure calculations. It is a platform-independent Fortran 90 code using a hybrid MPI+X programming model. For CPU platforms the application has a robust and optimized OpenMP implementation for shared memory parallelism. As part of the NESAP application readiness program for NERSC's latest Perlmutter system, MFDn has been updated to take advantage of accelerators. The current mainline GPU port is based on OpenACC. In this work we describe some of the key challenges of creating an efficient GPU implementation. Additionally, we compare the support of OpenMP and OpenACC on AMD and NVIDIA GPUs.