The performance of ITPACK on vector computers for solving large sparse linear systems arising in sample oil reseervoir simulation problems

Results are presented of the performance of two different versions of the ITPACK software package on large sparse linear systems arising in the solution of sample oil reservoir simulation problems using three different large vector computers (Cyber 205, Cray X-MP48 and Amdahl VP1200). The main focus of this paper is on the necessary changes in the package that were made for efficiency when going from a memory-to-memory computer to a register-to-register computer. We feel that these are typical changes that must be considered when moving software of this type between vector computers. The execution times presented should not be considered to be representative of the overall performance of these computers.