Can coercive formulations lead to fast and accurate solution of the Helmholtz equation?

JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS

卷:352

Article

Diwan, Ganesh C.¹  Moiola, Andrea²  Spence, Euan A.³ 

[1] UCL, Dept Med Phys & Biomed Engn, London WC1E 6BT, England

[2] Univ Pavia, Dept Math, I-27100 Pavia, Italy

[3] Univ Bath, Dept Math Sci, Bath BA2 7AY, Avon, England

关键词: Helmholtz equation;    Finite element method;    Coercive variational formulation;    Pollution effect;    Wavenumber-explicit analysis;    GMRES;   

DOI  :  10.1016/j.cam.2018.11.035

来源: Elsevier

【 摘 要 】

A new, coercive formulation of the Helmholtz equation was introduced in Moiola and Spence (2014). In this paper we investigate h-version Galerkin discretisations of this formulation, and the iterative solution of the resulting linear systems. We find that the coercive formulation behaves similarly to the standard formulation in terms of the pollution effect (i.e. to maintain accuracy as k -> infinity, h must decrease with k at the same rate as for the standard formulation). We prove k-explicit bounds on the number of GMRES iterations required to solve the linear system of the new formulation when it is preconditioned with a prescribed symmetric positive-definite matrix. Even though the number of iterations grows with k, these are the first such rigorous bounds on the number of GMRES iterations for a preconditioned formulation of the Helmholtz equation, where the preconditioner is a symmetric positive-definite matrix. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

Free