GPU-based conjugate gradient solver for lattice QCD with domain-wall fermions

Abstract

We present a GPU-based conjugate gradient (CG) solver for lattice QCD with domain-wall fermions (DWF). It is well-known that CG is the most time-consuming part in the Hybrid Monte Carlo simulation of unquenched lattice QCD, which becomes even more computational demanding for lattice QCD with exact chiral symmetry. We have implemented the CG for the general 5-dimensional DWF operator on NVIDIAR CUDATM architecture with mixed-precision, using the defect correction as well as the reliable updates algorithms. We optimize our computation by even-odd preconditioning and several innovative techniques for our CUDA kernels. For NVIDIA GeForceR GTX 285/480, our CG solver attains 180/233 Gflops (sustained).