QCDimMPI: MPI code for QCD with an improved action

QCDimMPI[I] is a simulation code for pure SU(3) gauge theory with an improv ed action consisting of 1 x 1 and 2 x 1 plaquettes. It uses Fortran77 and t he Message Passing Interface Standard, MPI[2]. QCDimMPI is an extended vers ion of QCDMPI. It is portable, allows simulations in any number of dimensio ns, on any number of processors, and with arbitrary dimensional partitionin g. It requires a rather small working area, and yields excellent performanc e on single processor computers and a wide variety of parallel computers wh ich support MPI. The program provides information on link update time and c ommunications time. In this paper, an outline of QCDimMPI is given, and ben chmark results on several parallel computers are reported.