Based on numerical experiments with a cell-centred multigrid Poisson solver in one and two dimensions, we propose to use Alternating Coarse-Line Zebra ordering as a robust parallel smoother for the 2D case. The algorithm is presented based on a heuristic discussion, and the convergence rates obtained with different smoothers are compared. Local mode analysis is used to estimate the smoothing factor and two-level convergence for the method.

Math. Reviews 1991 Subject Classification: 65N22, 65N55, 65Y05