An Arnoldi-based approach to polynomial and rational least squares problems

Fuente: arXiv
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Autores principales: Faghih, Amin, Van Barel, Marc, Van Buggenhout, Niel, Vandebril, Raf
Formato: Preprint
Publicado: 2024
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author Faghih, Amin
Van Barel, Marc
Van Buggenhout, Niel
Vandebril, Raf
author_facet Faghih, Amin
Van Barel, Marc
Van Buggenhout, Niel
Vandebril, Raf
contents In this research, we solve polynomial, Sobolev polynomial, rational, and Sobolev rational least squares problems. Although the increase in the approximation degree allows us to fit the data better in attacking least squares problems, the ill-conditioning of the coefficient matrix fuels the dramatic decrease in the accuracy of the approximation at higher degrees. To overcome this drawback, we first show that the column space of the coefficient matrix is equivalent to a Krylov subspace. Then the connection between orthogonal polynomials or rational functions and orthogonal bases for Krylov subspaces in order to exploit Krylov subspace methods like Arnoldi orthogonalization is established. Furthermore, some examples are provided to illustrate the theory and the performance of the proposed approach.
format Preprint
id arxiv_https___arxiv_org_abs_2407_05945
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An Arnoldi-based approach to polynomial and rational least squares problems
Faghih, Amin
Van Barel, Marc
Van Buggenhout, Niel
Vandebril, Raf
Numerical Analysis
In this research, we solve polynomial, Sobolev polynomial, rational, and Sobolev rational least squares problems. Although the increase in the approximation degree allows us to fit the data better in attacking least squares problems, the ill-conditioning of the coefficient matrix fuels the dramatic decrease in the accuracy of the approximation at higher degrees. To overcome this drawback, we first show that the column space of the coefficient matrix is equivalent to a Krylov subspace. Then the connection between orthogonal polynomials or rational functions and orthogonal bases for Krylov subspaces in order to exploit Krylov subspace methods like Arnoldi orthogonalization is established. Furthermore, some examples are provided to illustrate the theory and the performance of the proposed approach.
title An Arnoldi-based approach to polynomial and rational least squares problems
topic Numerical Analysis
url https://arxiv.org/abs/2407.05945