A 3-LEVEL PARALLELIZATION OF SPATIAL DIRECT NUMERICAL-SIMULATION

The parallelization of a NASA Navier-Stokes simulation code is careful ly and systematically investigated. Based on numerical, dependence and partition analysis, three different levels of parallelization have be en proposed and implemented. The low-level parallelization is at the k ernel level. A previously developed parallel tridiagonal solver is use d for concurrent processing. The middle-level parallelization solves t he multiple right-hand-sides of the tridiagonal systems concurrently. The high-level parallelization is at the level of time step iterations . A PVM implementation of the parallelization has been accomplished. D ifferent communication patterns and different PVM communication calls have been examined for best performance. The parallelized code has bee n tested on two parallel platforms, a cluster of workstations availabl e at Louisiana State University and the IBM SP2 parallel computer avai lable at Cornell Supercomputing Center. Experimental results confirm o ur analytical findings: the three-level parallelization is feasible an d effective. A linear speedup is measured. In addition to parallelizat ion, through profiling and performance analysis, the original sequenti al code is optimized as well. (C) 1998 Published by Elsevier Science L imited. All rights reserved.