tmLQCD: A program suite to simulate Wilson twisted mass lattice QCD

We discuss a program suite for simulating Quantum Chromodynamics on a 4-dimensional space–time lattice. The basic Hybrid Monte Carlo algorithm is introduced and a number of algorithmic improvements are explained. We then discuss the implementations of these concepts as well as our parallelisation strategy in the actual simulation code. Finally, we provide a user guide to compile and run the program.Program summaryProgram title: tmLQCDCatalogue identifier: AEEH_v1_0Program summary URL::http://cpc.cs.qub.ac.uk/summaries/AEEH_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GNU General Public Licence (GPL)No. of lines in distributed program, including test data, etc.: 122 768No. of bytes in distributed program, including test data, etc.: 931 042Distribution format: tar.gzProgramming language: C and MPIComputer: anyOperating system: any with a standard C compilerHas the code been vectorised or parallelised?: Yes. One or optionally any even number of processors may be used. Tested with up to 32 768 processorsRAM: no typical values availableClassification: 11.5External routines: LAPACK [1] and LIME [2] libraryNature of problem: Quantum ChromodynamicsSolution method: Markov Chain Monte Carlo using the Hybrid Monte Carlo algorithm with mass preconditioning and multiple time scales [3]. Iterative solver for large systems of linear equations.Restrictions: Restricted to an even number of (not necessarily mass degenerate) quark flavours in the Wilson or Wilson twisted mass formulation of lattice QCD.Running time: Depending on the problem size, the architecture and the input parameters from a few minutes to weeks.References:[1]http://www.netlib.org/lapack/.[2]USQCD, http://usqcd.jlab.org/usqcd-docs/c-lime/.[3]C. Urbach, K. Jansen, A. Shindler, U. Wenger, Comput. Phys. Commun. 174 (2006) 87, hep-lat/0506011.