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Main Authors: Goodwill, Tristan, Greengard, Leslie, Hoskins, Jeremy, Rachh, Manas, Wang, Yuguan
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.05458
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author Goodwill, Tristan
Greengard, Leslie
Hoskins, Jeremy
Rachh, Manas
Wang, Yuguan
author_facet Goodwill, Tristan
Greengard, Leslie
Hoskins, Jeremy
Rachh, Manas
Wang, Yuguan
contents In this work we present a variant of the fast multipole method (FMM) for efficiently evaluating standard layer potentials on geometries with complex coordinates in two and three dimensions. The complex scaled boundary integral method for the efficient solution of scattering problems on unbounded domains results in complex point locations upon discretization. Classical real-coordinate FMMs are no longer applicable, hindering the use of this approach for large-scale problems. Here we develop the complex-coordinate FMM based on the analytic continuation of certain special function identities used in the construction of the classical FMM. To achieve the same linear time complexity as the classical FMM, we construct a hierarchical tree based solely on the real parts of the complex point locations, and derive convergence rates for truncated expansions when the imaginary parts of the locations are a Lipschitz function of the corresponding real parts. We demonstrate the efficiency of our approach through several numerical examples and illustrate its application for solving large-scale time-harmonic water wave problems and Helmholtz transmission problems.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05458
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fast Multipole Method with Complex Coordinates
Goodwill, Tristan
Greengard, Leslie
Hoskins, Jeremy
Rachh, Manas
Wang, Yuguan
Numerical Analysis
In this work we present a variant of the fast multipole method (FMM) for efficiently evaluating standard layer potentials on geometries with complex coordinates in two and three dimensions. The complex scaled boundary integral method for the efficient solution of scattering problems on unbounded domains results in complex point locations upon discretization. Classical real-coordinate FMMs are no longer applicable, hindering the use of this approach for large-scale problems. Here we develop the complex-coordinate FMM based on the analytic continuation of certain special function identities used in the construction of the classical FMM. To achieve the same linear time complexity as the classical FMM, we construct a hierarchical tree based solely on the real parts of the complex point locations, and derive convergence rates for truncated expansions when the imaginary parts of the locations are a Lipschitz function of the corresponding real parts. We demonstrate the efficiency of our approach through several numerical examples and illustrate its application for solving large-scale time-harmonic water wave problems and Helmholtz transmission problems.
title Fast Multipole Method with Complex Coordinates
topic Numerical Analysis
url https://arxiv.org/abs/2509.05458