Abstract
We propose an iterative solution method for the three-dimensional high-frequency Helmholtz equation that exploits a contour integral formulation of spectral projectors. In this framework, the solution in certain invariant subspaces is approximated by solving complex-shifted linear systems, resulting in faster GMRES iterations due to the restricted spectrum. The shifted systems are solved by exploiting a polynomial fixed-point iteration, which is a robust scheme even if the magnitude of the shift is small. Numerical tests in three dimensions indicate that O(n1/3) matrix-vector products are needed to solve a high-frequency problem with a matrix size n with high accuracy. The method has a small storage requirement, can be applied to both dense and sparse linear systems, and is highly parallelizable.
Original language | English (US) |
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Pages (from-to) | 58-82 |
Number of pages | 25 |
Journal | SIAM Journal on Matrix Analysis and Applications |
Volume | 41 |
Issue number | 1 |
DOIs | |
State | Published - 2020 |
Externally published | Yes |
Bibliographical note
Funding Information:∗Received by the editors November 21, 2018; accepted for publication (in revised form) by L. Giraud November 4, 2019; published electronically January 9, 2020. https://doi.org/10.1137/18M1228128 Funding: The work of the second and third authors was supported by National Science Foundation grant DMS-1521573 and the Minnesota Supercomputing Institute. The work of the fourth author was supported by the Simons Foundation under the MATH + X program, National Science Foundation grant DMS-1559587, the corporate members of the Geo-Mathematical Group at Rice University, and Total. †Department of Computational and Applied Mathematics, Rice University, Houston, TX 77005 ([email protected], [email protected]). ‡Department of Mathematics, Emory University, Atlanta, GA 30322 ([email protected]). §Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455 ([email protected]).
Publisher Copyright:
© 2020 Society for Industrial and Applied Mathematics
Keywords
- Cauchy integral
- Helmholtz preconditioner
- Polynomial iteration
- Shifted Laplacian