An improved sweeping domain decomposition preconditioner for the Helmholtz equation

TL;DR

This paper presents an enhanced domain decomposition preconditioner for the Helmholtz equation that improves parallelization and efficiency, significantly reducing computation time and memory requirements for large-scale problems.

Contribution

The authors introduce an improved transmission method using perfectly matched layers and incorporate simultaneous sweeps and a two-grid iteration, advancing the state-of-the-art in Helmholtz problem solvers.

Findings

Substantial decrease in computation time.

Reduced memory usage.

Comparable performance to fastest existing methods.

Abstract

In this paper we generalize and improve a recently developed domain decomposition preconditioner for the iterative solution of discretized Helmholtz equations. We introduce an improved method for transmission at the internal boundaries using perfectly matched layers. Simultaneous forward and backward sweeps are introduced, thereby improving the possibilities for parallellization. Finally, the method is combined with an outer two-grid iteration. The method is studied theoretically and with numerical examples. It is shown that the modifications lead to substantial decreases in computation time and memory use, so that computation times become comparable to that of the fastests methods currently in the literature for problems with up to 10^8 degrees of freedom.