PAIR INTERACTION LATTICE GAS ON GENERAL PURPOSE COMPUTERS: FORTRAN OR C?

We report on performance tests of pair interaction lattice gas automata in two and three dimensions coded in FORTRAN and C. The programs have been run on ALLIANT/FX-80, ALLIANT/FX-2800, CONVEX C2, CRAY-YMP, NEC/SX3, and SUN/IPC. The maximum update rates are 200 million site updates per second on the NEC/SX3 (FORTRAN), 117 (2D version) and 29 (3D version) on the CRAY-YMP (C). As a byproduct we give results for the performance of integer arithmetic and bit operations. Usually the C-programs were somewhat faster than the FORTRAN-programs except on the NEC/SX3 where the C-compiler was not able to vectorize the main loops.