Convergence of Restarted Krylov Subspace Methods for Stieltjes Functions of Matrices
Convergence of Restarted Krylov Subspace Methods for Stieltjes Functions of Matrices
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DOI:
10.1137/140973463
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发表时间:
2014-12
期刊:
影响因子:
--
通讯作者:
A. Frommer;S. Güttel;M. Schweitzer
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文献类型:
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作者:
A. Frommer;S. Güttel;M. Schweitzer
To approximate $f(A){b}$---the action of a matrix function on a vector---by a Krylov subspace method, restarts may become mandatory due to storage requirements for the Arnoldi basis or due to the growing computational complexity of evaluating $f$ on a Hessenberg matrix of growing size. A number of restarting methods have been proposed in the literature in recent years and there has been substantial algorithmic advancement concerning their stability and computational efficiency. However, the question under which circumstances convergence of these methods can be guaranteed has remained largely unanswered. In this paper we consider the class of Stieltjes functions and a related class, which contain important functions like the (inverse) square root and the matrix logarithm. For these classes of functions we present new theoretical results which prove convergence for Hermitian positive definite matrices $A$ and arbitrary restart lengths. We also propose a modification of the Arnoldi approximation which guaran...