A Low-Memory Lanczos Method with Rational Krylov Compression for Matrix Functions: A low-memory Lanczos method with rational Krylov compression for matrix functions

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Názov: A Low-Memory Lanczos Method with Rational Krylov Compression for Matrix Functions: A low-memory Lanczos method with rational Krylov compression for matrix functions
Autori: Angelo A. Casulli, Igor Simunec
Zdroj: SIAM Journal on Scientific Computing. 47:A1358-A1382
Publication Status: Preprint
Informácie o vydavateľovi: Society for Industrial & Applied Mathematics (SIAM), 2025.
Rok vydania: 2025
Predmety: Numerical computation of matrix exponential and similar matrix functions, Computational methods for sparse matrices, matrix function, 65F60, 65F50, Mathematics - Numerical Analysis, rational Krylov, low memory
Popis: In this work we introduce a memory-efficient method for computing the action of a Hermitian matrix function on a vector. Our method consists of a rational Lanczos algorithm combined with a basis compression procedure based on rational Krylov subspaces that only involve small matrices. The cost of the compression procedure is negligible with respect to the cost of the Lanczos algorithm. This enables us to avoid storing the whole Krylov basis, leading to substantial reductions in memory requirements. This method is particularly effective when the rational Lanczos algorithm needs a significant number of iterations to converge and each iteration involves a low computational effort. This scenario often occurs when polynomial Lanczos, as well as extended and shift-and-invert Lanczos are employed. Theoretical results prove that, for a wide variety of functions, the proposed algorithm differs from rational Lanczos by an error term that is usually negligible. The algorithm is compared with other low-memory Krylov methods from the literature on a variety of test problems, showing competitive performance.
Comment: 26 pages, 3 figures, 4 tables
Druh dokumentu: Article
Popis súboru: application/xml
Jazyk: English
ISSN: 1095-7197
1064-8275
DOI: 10.1137/24m1644699
Prístupová URL adresa: http://arxiv.org/abs/2403.04390
Prístupové číslo: edsair.doi.dedup.....2fbdf4840ea9ea0ce313b66a694da2b0
Databáza: OpenAIRE
Popis
Abstrakt:In this work we introduce a memory-efficient method for computing the action of a Hermitian matrix function on a vector. Our method consists of a rational Lanczos algorithm combined with a basis compression procedure based on rational Krylov subspaces that only involve small matrices. The cost of the compression procedure is negligible with respect to the cost of the Lanczos algorithm. This enables us to avoid storing the whole Krylov basis, leading to substantial reductions in memory requirements. This method is particularly effective when the rational Lanczos algorithm needs a significant number of iterations to converge and each iteration involves a low computational effort. This scenario often occurs when polynomial Lanczos, as well as extended and shift-and-invert Lanczos are employed. Theoretical results prove that, for a wide variety of functions, the proposed algorithm differs from rational Lanczos by an error term that is usually negligible. The algorithm is compared with other low-memory Krylov methods from the literature on a variety of test problems, showing competitive performance.<br />Comment: 26 pages, 3 figures, 4 tables
ISSN:10957197
10648275
DOI:10.1137/24m1644699