Print Email Facebook Twitter An efficient two-level preconditioner for multi-frequency wave propagation problems Title An efficient two-level preconditioner for multi-frequency wave propagation problems Author Baumann, M.M. (TU Delft Numerical Analysis) van Gijzen, M.B. (TU Delft Numerical Analysis) Date 2019 Abstract We consider wave propagation problems that are modeled in the frequency-domain, and that need to be solved simultaneously for multiple frequencies within a fixed range. For this, a single shift-and-invert preconditioner at a so-called seed frequency is applied. The choice of the seed is crucial for the performance of preconditioned multi-shift GMRES and is closely related to the parameter choice for the Complex Shifted Laplace preconditioner. Based on a classical GMRES convergence bound, we present an analytic formula for the optimal seed parameter that purely depends on the original frequency range. The new insight is exploited in a two-level preconditioning strategy: A shifted Neumann preconditioner with minimized spectral radius is additionally applied to multi-shift GMRES. Moreover, we present a reformulation of the multi-shift problem to a matrix equation solved with, for instance, global GMRES. Here, our analysis allows for rotation of the spectrum of the linear operator. Numerical experiments for the time-harmonic visco-elastic wave equation demonstrate the performance of the new preconditioners. Subject Frequency-domain formulationMulti-shift GMRESPreconditioner designShift-and-invert preconditionerVisco-elastic wave equation To reference this document use: http://resolver.tudelft.nl/uuid:4e28fbc1-0102-42bc-9866-1ce7bdf71335 DOI https://doi.org/10.1016/j.apnum.2018.08.020 Embargo date 2021-11-02 ISSN 0168-9274 Source Applied Numerical Mathematics, 135, 316-332 Bibliographical note Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Part of collection Institutional Repository Document type journal article Rights © 2019 M.M. Baumann, M.B. van Gijzen Files PDF 1_s2.0_S016892741830196X_main.pdf 1.48 MB Close viewer /islandora/object/uuid:4e28fbc1-0102-42bc-9866-1ce7bdf71335/datastream/OBJ/view