Springer International Publishing AG, 2017. — 247 p. — (Geosystems Mathematics) — ISBN: 9783319288314.This edited volume offers a state of the art overview of fast and robust solvers for the Helmholtz equation. The book consists of three parts: new developments and analysis in Helmholtz solvers, practical methods and implementations of Helmholtz solvers, and industrial applications. The Helmholtz equation appears in a wide range of science and engineering disciplines in which wave propagation is modeled. Examples are: seismic inversion, ultrasone medical imaging, sonar detection of submarines, waves in harbours and many more. The partial differential equation looks simple but is hard to solve. In order to approximate the solution of the problem numerical methods are needed. First a discretization is done. Various methods can be used: (high order) Finite Difference Method, Finite Element Method, Discontinuous Galerkin Method and Boundary Element Method. The resulting linear system is large, where the size of the problem increases with increasing frequency. Due to higher frequencies the seismic images need to be more detailed and, therefore, lead to numerical problems of a larger scale. To solve these three dimensional problems fast and robust, iterative solvers are required. However for standard iterative methods the number of iterations to solve the system becomes too large. For these reason a number of new methods are developed to overcome this hurdle. The book is meant for researchers both from academia and industry and graduate students. A prerequisite is knowledge on partial differential equations and numerical linear algebra. Table of contents Recent Results on Domain Decomposition Preconditioning for the High-Frequency Helmholtz Equation Using Absorption High Order Transparent Boundary Conditions for the Helmholtz Equation On the Optimality of Shifted Laplacian in a Class of Polynomial Preconditioners for the Helmholtz Equation How to Choose the Shift in the Shifted Laplace Preconditioner for the Helmholtz Equation Combined with Deflation The Multilevel Krylov-Multigrid Method for the Helmholtz Equation Preconditioned by the Shifted Laplacian A Geometric Multigrid Preconditioner for the Solution of the Helmholtz Equation in Three-Dimensional Heterogeneous Media on Massively Parallel Computers Some Computational Aspects of the Time and Frequency Domain Formulations of Seismic Waveform Inversion Optimized Schwarz Domain Decomposition Methods for Scalar and Vector Helmholtz Equations Computationally Efficient Boundary Element Methods for High-Frequency Helmholtz Problems in Unbounded Domains
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