OpenACC programs of the Swendsen–Wang multi-cluster spin flip algorithm

Abstract

We present sample OpenACC programs of the Swendsen–Wang multi-cluster spin flip algorithm. OpenACC is a directive-based programming model for accelerators without requiring modification to the underlying CPU code itself. In this paper, we deal with the classical spin models as with the sample CUDA programs (Komura and Okabe, 2014), that is, two-dimensional (2D) Ising model, three-dimensional (3D) Ising model, 2D Potts model, 3D Potts model, 2D XY model and 3D XY model. We explain the details of sample OpenACC programs and compare the performance of the present OpenACC implementations with that of the CUDA implementations for the 2D and 3D Ising models and the 2D and 3D XY models. Program summaryProgram title: SWspin_OpenACCCatalogue identifier: AEXU_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEXU_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 2898No. of bytes in distributed program, including test data, etc.: 9729Distribution format: tar.gzProgramming language: C, OpenACC.Computer: Any computer with an OpenACC-enabled accelerator (tested on NVIDIA GPU).Operating system: No limits (tested on Linux).RAM: About 1MiB for the parameters used in the sample programs.Classification: 23.Nature of problem: Monte Carlo simulation of classical spin systems. Ising model, q-state Potts model, and the classical XY model are treated for both two-dimensional and three-dimensional lattices.Solution method: Swendsen–Wang multi-cluster spin flip Monte Carlo method. The OpenACC implementation for the cluster-labeling is based on the work by Kalentev et al. [J. Parallel Distrib. Comput. 71 (2011) 615–620].Restrictions: The system size is limited depending on the memory of an accelerator.Running time: A few minutes per each program for the parameters used in the sample program.