Stability and preconditioning for a hybrid approximation on the sphere

This paper proposes a new preconditioning scheme for a linear system with a saddle-point structure arising from a hybrid approximation scheme on the sphere, an approximation scheme that combines (local) spherical radial basis functions and (global) spherical polynomials. In principle the resulting l...

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Main Authors: Le Gia, QT, Sloan, IH, Wathen, AJ
Format: Journal article
Language:English
Published: Springer 2011
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author Le Gia, QT
Sloan, IH
Wathen, AJ
author_facet Le Gia, QT
Sloan, IH
Wathen, AJ
author_sort Le Gia, QT
collection OXFORD
description This paper proposes a new preconditioning scheme for a linear system with a saddle-point structure arising from a hybrid approximation scheme on the sphere, an approximation scheme that combines (local) spherical radial basis functions and (global) spherical polynomials. In principle the resulting linear system can be preconditioned by the block-diagonal preconditioner of Murphy, Golub and Wathen. Making use of a recently derived inf-sup condition and the Brezzi stability and convergence theorem for this approximation scheme, we show that in this context the Schur complement in the above preconditioner is spectrally equivalent to a certain non-constant diagonal matrix. Numerical experiments with a non-uniform distribution of data points support the theoretically proved quality of the new preconditioner. © 2011 Springer-Verlag.
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spelling oxford-uuid:8376bb26-6c01-4605-9d3c-7fa201b24fb42022-05-13T14:19:36ZStability and preconditioning for a hybrid approximation on the sphereJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8376bb26-6c01-4605-9d3c-7fa201b24fb4EnglishSymplectic Elements at OxfordSpringer2011Le Gia, QTSloan, IHWathen, AJThis paper proposes a new preconditioning scheme for a linear system with a saddle-point structure arising from a hybrid approximation scheme on the sphere, an approximation scheme that combines (local) spherical radial basis functions and (global) spherical polynomials. In principle the resulting linear system can be preconditioned by the block-diagonal preconditioner of Murphy, Golub and Wathen. Making use of a recently derived inf-sup condition and the Brezzi stability and convergence theorem for this approximation scheme, we show that in this context the Schur complement in the above preconditioner is spectrally equivalent to a certain non-constant diagonal matrix. Numerical experiments with a non-uniform distribution of data points support the theoretically proved quality of the new preconditioner. © 2011 Springer-Verlag.
spellingShingle Le Gia, QT
Sloan, IH
Wathen, AJ
Stability and preconditioning for a hybrid approximation on the sphere
title Stability and preconditioning for a hybrid approximation on the sphere
title_full Stability and preconditioning for a hybrid approximation on the sphere
title_fullStr Stability and preconditioning for a hybrid approximation on the sphere
title_full_unstemmed Stability and preconditioning for a hybrid approximation on the sphere
title_short Stability and preconditioning for a hybrid approximation on the sphere
title_sort stability and preconditioning for a hybrid approximation on the sphere
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