Approximation on disjoint intervals and its applicability to matrix preconditioning

Maurice Hasson, Juan M. Restrepo

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

A polynomial preconditioner to an invertible matrix is constructed from the (near) best uniform polynomial approximation to the function 1/x on the eigenvalues of the matrix. The preconditioner is developed using symmetric matrices whose eigenvalues are located in the union of two (disjoint) intervals. The full spectrum of the matrix need not be known in order for the strategy to be applicable. All that is essential is an estimate on the bounds of the larger of the two clusters of eigenvalues. The algorithm, based on the strategy, is shown to be numerically stable with respect to the size of the matrix. In fact it yields, at low cost, an approximation to the inverse of the matrix to within a specified tolerance.

Original languageEnglish
Pages (from-to)757-769
Number of pages13
JournalComplex Variables and Elliptic Equations
Volume52
Issue number9
DOIs
StatePublished - 2007
Externally publishedYes

Funding

The authors wish to express their appreciation to James Hyman and Rob Indik for very fruitful discussions. JMR is supported by a DOE ‘Early Career’ grant DE-FG02-02ER25533. JMR also thanks T7 at Los Alamos, where much of this work was performed. MH was supported by a NSF/VIGRE fellowship.

FundersFunder number
VIGRE
National Science Foundation
U.S. Department of EnergyDE-FG02-02ER25533

    Keywords

    • 41A05
    • 41A25
    • 41A28
    • 65F10
    • 65F15
    • AMS Subject Classifications
    • Matrix preconditioning
    • Normal matrices
    • Polynomial approximation

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