PWDFT-SW: Extending the Limit of Plane-Wave DFT Calculations to 16K Atoms on the New Sunway Supercomputer

TL;DR

This paper introduces a highly optimized parallel implementation of plane wave DFT tailored for the Sunway supercomputer, significantly reducing computational costs and enabling large-scale simulations of thousands of atoms.

Contribution

The authors develop a novel, system-specific parallel implementation of PWDFT that extends the scale of feasible simulations on Sunway supercomputers.

Findings

Achieved a 64.8x speedup for 4096 silicon atoms

Enabled DFT calculations for systems with up to 16,384 carbon atoms

Reduced both computational costs and memory usage significantly

Abstract

First-principles density functional theory (DFT) with plane wave (PW) basis set is the most widely used method in quantum mechanical material simulations due to its advantages in accuracy and universality. However, a perceived drawback of PW-based DFT calculations is their substantial computational cost and memory usage, which currently limits their ability to simulate large-scale complex systems containing thousands of atoms. This situation is exacerbated in the new Sunway supercomputer, where each process is limited to a mere 16 GB of memory. Herein, we present a novel parallel implementation of plane wave density functional theory on the new Sunway supercomputer (PWDFT-SW). PWDFT-SW fully extracts the benefits of Sunway supercomputer by extensively refactoring and calibrating our algorithms to align with the system characteristics of the Sunway system. Through extensive numerical experiments, we demonstrate that our methods can substantially decrease both computational costs and memory usage. Our optimizations translate to a speedup of 64.8x for a physical system containing 4,096 silicon atoms, enabling us to push the limit of PW-based DFT calculations to large-scale systems containing 16,384 carbon atoms.