206	1998	Bertil Gustafsson and Lina Hemmingsson	lina@tdb.uu.se	A fast domain decomposition high order Poisson solver

                      Abstract

In this paper we present a fast high order Poisson solver for
implementation on parallel computers. The method uses deferred
correction, such that high order accuracy is obtained by solving a
sequence of systems with a narrow stencil on the left hand side. These
systems are solved by a domain decomposition method. The method is
direct in the sense that for any given order of accuracy, the number
of arithmetic operations is fixed. Numerical experiments show that
these high order solvers easily outperform standard second order
ones. The very fast algorithm in combination with the coarser grid
allowed for by the high order method, also makes it quite possible to
compete with adaptive methods and irregular grids for problems with
solutions containing widely different scales.