Blocking structures, approximation, and preconditioning

Fuente: arXiv
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Autores principales: Barakitis, Nikos, Donatelli, Marco, Ferri, Samuele, Loi, Valerio, Serra-Capizzano, Stefano, Sormani, Rosita Luisa
Formato: Preprint
Publicado: 2025
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author Barakitis, Nikos
Donatelli, Marco
Ferri, Samuele
Loi, Valerio
Serra-Capizzano, Stefano
Sormani, Rosita Luisa
author_facet Barakitis, Nikos
Donatelli, Marco
Ferri, Samuele
Loi, Valerio
Serra-Capizzano, Stefano
Sormani, Rosita Luisa
contents We consider block-structured matrices $A_n$, where the blocks are of (block) unilevel Toeplitz type with $s\times t$ matrix-valued generating functions. Under mild assumptions on the size of the (rectangular) blocks, the asymptotic distribution of the singular values of {the} associated matrix-sequences is identified and, when the related singular value symbol is Hermitian, it coincides with the spectral symbol. Building on the theoretical derivations, we approximate the matrices with simplified block structures that show two important features: a) the related simplified matrix-sequence has the same distributions as $\{A_{n}\}_{n}$; b) a generic linear system involving the simplified structures can be solved in $O(n\log n)$ arithmetic operations. The two key properties a) and b) suggest a natural way for preconditioning a linear system with coefficient matrix $A_n$. Under mild assumptions, the singular value analysis and the spectral analysis of the preconditioned matrix-sequences is provided, together with a wide set of numerical experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2501_14874
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Blocking structures, approximation, and preconditioning
Barakitis, Nikos
Donatelli, Marco
Ferri, Samuele
Loi, Valerio
Serra-Capizzano, Stefano
Sormani, Rosita Luisa
Numerical Analysis
65F08, 15A18, 15B05
We consider block-structured matrices $A_n$, where the blocks are of (block) unilevel Toeplitz type with $s\times t$ matrix-valued generating functions. Under mild assumptions on the size of the (rectangular) blocks, the asymptotic distribution of the singular values of {the} associated matrix-sequences is identified and, when the related singular value symbol is Hermitian, it coincides with the spectral symbol. Building on the theoretical derivations, we approximate the matrices with simplified block structures that show two important features: a) the related simplified matrix-sequence has the same distributions as $\{A_{n}\}_{n}$; b) a generic linear system involving the simplified structures can be solved in $O(n\log n)$ arithmetic operations. The two key properties a) and b) suggest a natural way for preconditioning a linear system with coefficient matrix $A_n$. Under mild assumptions, the singular value analysis and the spectral analysis of the preconditioned matrix-sequences is provided, together with a wide set of numerical experiments.
title Blocking structures, approximation, and preconditioning
topic Numerical Analysis
65F08, 15A18, 15B05
url https://arxiv.org/abs/2501.14874