High Performance Parallel Multigrid Algorithms
                            for Unstructured Grids

                             Paul O. Frederickson
                          Math Cube Associates, Inc.
                       PO Box 66, Los Alamos, NM 87544


We describe a high performance parallel multigrid algorithm for a rather
general class of unstructured grid problems in two and three dimensions.  The
algorithm PUMG is related in structure to the parallel multigrid algorithm
PSMG introduced by McBryan and Frederickson, for they both obtain a higher
convergence rate through the use of multiple coarse grids.  Another reason for
the high convergence rate of PUMG is its smoother, an approximate inverse
developed by Baumgardner and Frederickson.