A mixed interpolation-regression method for numerical integration on the unit circle using zeros of para-orthogonal polynomials

Fuente: arXiv
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Main Authors: Cruz-Barroso, Ruymán, Fernández, Lidia, Marcellán, Francisco
Format: Preprint
Published: 2026
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author Cruz-Barroso, Ruymán
Fernández, Lidia
Marcellán, Francisco
author_facet Cruz-Barroso, Ruymán
Fernández, Lidia
Marcellán, Francisco
contents A new alternative numerical procedure to the Szegő quadrature formulas for the estimation of integrals with respect to a positive Borel measure $μ$ supported on the unit circle is presented. As in many practical situations, we assume that the values of the integrand $F$ are only known at a finite number of points, which we will assume to be uniformly distributed on the unit circle (although this does not actually constitute a restriction). Our technique consists of obtaining an approximating Laurent polynomial $L$ to $F$ by interpolation in the Hermite sense in a collection of these points that mimic the zeros of a para-orthogonal polynomial with respect to $μ$, and to use the values of $F$ at the remaining nodes to improve the accuracy of the approximation by a process of simultaneous complex regression. Some numerical examples are carried out.
format Preprint
id arxiv_https___arxiv_org_abs_2601_18721
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A mixed interpolation-regression method for numerical integration on the unit circle using zeros of para-orthogonal polynomials
Cruz-Barroso, Ruymán
Fernández, Lidia
Marcellán, Francisco
Numerical Analysis
33C45, 42C05, 65D32, 41A55, 62J05
A new alternative numerical procedure to the Szegő quadrature formulas for the estimation of integrals with respect to a positive Borel measure $μ$ supported on the unit circle is presented. As in many practical situations, we assume that the values of the integrand $F$ are only known at a finite number of points, which we will assume to be uniformly distributed on the unit circle (although this does not actually constitute a restriction). Our technique consists of obtaining an approximating Laurent polynomial $L$ to $F$ by interpolation in the Hermite sense in a collection of these points that mimic the zeros of a para-orthogonal polynomial with respect to $μ$, and to use the values of $F$ at the remaining nodes to improve the accuracy of the approximation by a process of simultaneous complex regression. Some numerical examples are carried out.
title A mixed interpolation-regression method for numerical integration on the unit circle using zeros of para-orthogonal polynomials
topic Numerical Analysis
33C45, 42C05, 65D32, 41A55, 62J05
url https://arxiv.org/abs/2601.18721