Singular vector spaces for computing the structured distance to singularity

Fuente: arXiv
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Auteur principal: Nyman, Lauri
Format: Preprint
Publié: 2026
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author Nyman, Lauri
author_facet Nyman, Lauri
contents Finding the distance to singularity for a matrix is a ubiquitous problem in numerical linear algebra, and is elegantly solved by the Eckart-Young-Mirsky theorem. Its structured variant naturally emerges when one considers structured matrices, and wants to preserve their structure. Recent work has shown that this problem is particularly important for a class of matrix nearness problems that either entirely or partly reduce to a structured distance to singularity problem. In this work, we propose a new framework for addressing this problem, based on the concept of singular vector spaces, that is, linear subsets of the set of singular matrices. We analyze singular vector spaces in the context of this problem, prove new results, and detail how a specific subfamily of singular vector spaces can be incorporated into a practical algorithm. The resulting algorithm is based on globally minimizing a certain objective function alternatingly in its arguments. Numerical experiments demonstrate that this new algorithm is remarkably faster than the state-of-the-art, while the quality of the output remains comparable. This makes it possible to solve problems of much larger size than what was previously possible.
format Preprint
id arxiv_https___arxiv_org_abs_2603_01233
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Singular vector spaces for computing the structured distance to singularity
Nyman, Lauri
Numerical Analysis
15A99, 65F22, 65F99, 65K99
Finding the distance to singularity for a matrix is a ubiquitous problem in numerical linear algebra, and is elegantly solved by the Eckart-Young-Mirsky theorem. Its structured variant naturally emerges when one considers structured matrices, and wants to preserve their structure. Recent work has shown that this problem is particularly important for a class of matrix nearness problems that either entirely or partly reduce to a structured distance to singularity problem. In this work, we propose a new framework for addressing this problem, based on the concept of singular vector spaces, that is, linear subsets of the set of singular matrices. We analyze singular vector spaces in the context of this problem, prove new results, and detail how a specific subfamily of singular vector spaces can be incorporated into a practical algorithm. The resulting algorithm is based on globally minimizing a certain objective function alternatingly in its arguments. Numerical experiments demonstrate that this new algorithm is remarkably faster than the state-of-the-art, while the quality of the output remains comparable. This makes it possible to solve problems of much larger size than what was previously possible.
title Singular vector spaces for computing the structured distance to singularity
topic Numerical Analysis
15A99, 65F22, 65F99, 65K99
url https://arxiv.org/abs/2603.01233