Technical Report WM - CS - 2010 - 03 College of William & Mary Department of Computer Science WM - CS - 2010 - 03 Implementing the Dslash Operator in OpenCL

The Dslash operator is used in Lattice Quantum Chromodymamics (LQCD) applications to implement a Wilson-Dirac sparse matrix-vector product. Typically the Dslash operation has been implemented as a parallel program. Today’s Graphics Processing Units (GPU) are designed to do highly parallel numerical calculations for 3D graphics rendering. This design works well with scientific applications such as LQCD’s implementation of the Dslash operator. The Scientific Computing group at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) has implemented the Dslash operator for execution on GPUs using NVIDIA’s Compute Unified Device Architecture (CUDA). CUDA applications, however, will only run on NVIDIA hardware. OpenCL (Open Computing Language) is a new open standard for developing parallel programs across CPUs, GPUs and other processors. This paper describes the implementation of the Dslash operator using OpenCL (Open Computing Language), its performance on NVIDIA GPUs compared with CUDA, and its performance on other hardware platforms. General Terms Performance, Languages.