Comparison of 2nd and 4th Order Discretizations
                        for Multigrid Poisson Solvers

                Murli M. Gupta, Jules Kouatchou and Jun Zhang 

                          Department of Mathematics 
                      The George Washington University 
                          Washington, DC 20052, USA

We combine a compact high-order difference approximation with multigrid
V-cycle algorithm to solve the two dimensional Poisson equation with Dirichlet
boundary conditions.  This scheme, along with several different orderings of
grid space and projection operators, is compared with the five-point formula
to show the dramatic improvement in computed accuracy, on serial and vector
machines.

Please send your comments to: zhang@math.gwu.edu