Scalable GW software for quasiparticle properties using OpenAtom

TL;DR

This paper introduces a highly parallelized GW software built on OpenAtom, enabling efficient large-scale electronic excitation calculations with improved scalability on supercomputers.

Contribution

Development of a massively-parallel GW software within OpenAtom that optimizes computational efficiency for large systems.

Findings

Significantly improved parallel scaling on supercomputers

Efficient implementation of GW calculations for large systems

Demonstrated performance on Mira and Blue Waters supercomputers

Abstract

The GW method, which can describe accurately electronic excitations, is one of the most widely used ab initio electronic structure technique and allows the physics of both molecular and condensed phase materials to be studied. However, the applications of the GW method to large systems require supercomputers and highly parallelized software to overcome the high computational complexity of the method scaling as $O(N^4)$. Here, we develop efficient massively-parallel GW software for the plane-wave basis set by revisiting the standard GW formulae in order to discern the optimal approaches for each phase of the GW calculation for massively parallel computation. These best numerical practices are implemented into the OpenAtom software which is written on top of charm++ parallel framework. We then evaluate the performance of our new software using range of system sizes. Our GW software shows significantly improved parallel scaling compared to publically available GW software on the Mira and Blue Waters supercomputers, two of largest most powerful platforms in the world.