Shifted HSS solvers for the indefinite Helmholtz equation

Fuente: arXiv
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Autori principali: Cotter, Colin J, Knook, Kars, Hope-Collins, Joshua
Natura: Preprint
Pubblicazione: 2025
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author Cotter, Colin J
Knook, Kars
Hope-Collins, Joshua
author_facet Cotter, Colin J
Knook, Kars
Hope-Collins, Joshua
contents We provide an iterative solution approach for the indefinite Helmholtz equation discretised using finite elements, based upon a Hermitian Skew-Hermitian Splitting (HSS) iteration applied to the shifted operator, and prove that the iteration is k- and mesh-robust when O(k) HSS iterations are performed. The HSS iterations involve solving a shifted operator that is suitable for approximation by multigrid using standard smoothers and transfer operators, and hence we can use O(N) parallel processors in a high performance computing implementation, where N is the total number of degrees of freedom. We argue that the algorithm converges in O(k) wallclock time when within the range of scalability of the multigrid. We provide numerical results in both 2D and 3D verifying our proofs and demonstrating this claim, establishing a method that can make use of large scale high performance computing systems.
format Preprint
id arxiv_https___arxiv_org_abs_2506_18694
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Shifted HSS solvers for the indefinite Helmholtz equation
Cotter, Colin J
Knook, Kars
Hope-Collins, Joshua
Numerical Analysis
We provide an iterative solution approach for the indefinite Helmholtz equation discretised using finite elements, based upon a Hermitian Skew-Hermitian Splitting (HSS) iteration applied to the shifted operator, and prove that the iteration is k- and mesh-robust when O(k) HSS iterations are performed. The HSS iterations involve solving a shifted operator that is suitable for approximation by multigrid using standard smoothers and transfer operators, and hence we can use O(N) parallel processors in a high performance computing implementation, where N is the total number of degrees of freedom. We argue that the algorithm converges in O(k) wallclock time when within the range of scalability of the multigrid. We provide numerical results in both 2D and 3D verifying our proofs and demonstrating this claim, establishing a method that can make use of large scale high performance computing systems.
title Shifted HSS solvers for the indefinite Helmholtz equation
topic Numerical Analysis
url https://arxiv.org/abs/2506.18694