Deflation acceleration of lattice QCD simulations

TL;DR

This paper demonstrates that propagating domain-decomposed deflation subspaces along HMC trajectories significantly accelerates lattice QCD simulations near the chiral limit, reducing computational time and improving scaling.

Contribution

It introduces a method to propagate deflation subspaces during HMC, enhancing efficiency in lattice QCD simulations close to the chiral limit.

Findings

Reduced computational time for lattice QCD simulations.

Improved scaling behavior with respect to quark mass.

Effective propagation of deflation subspaces along HMC trajectories.

Abstract

Close to the chiral limit, many calculations in numerical lattice QCD can potentially be accelerated using low-mode deflation techniques. In this paper it is shown that the recently introduced domain-decomposed deflation subspaces can be propagated along the field trajectories generated by the Hybrid Monte Carlo (HMC) algorithm with a modest effort. The quark forces that drive the simulation may then be computed using a deflation-accelerated solver for the lattice Dirac equation. As a consequence, the computer time required for the simulations is significantly reduced and an improved scaling behaviour of the simulation algorithm with respect to the quark mass is achieved.