Semicoarsening multigrid on distributed memory machines

This paper presents the results of a scalability study for a three-dimensio nal semi-coarsening multigrid solver on a distributed memory computer. In p articular, we are interested in the scalability of the solver how the solut ion time varies as both problem size and number of processors are increased . For an iterative linear solver, scalability involves both algorithmic iss ues and implementation issues. We examine the scalability of the solver the oretically by constructing a simple parallel model and experimentally by re sults obtained on an IBM SP. The results are compared with those obtained f or other solvers on the same computer.