Parameter choice strategies for regularized least squares approximation of noisy continuous functions on the unit circle

Fuente: arXiv
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Autores principales: An, Congpei, Cai, Mou
Formato: Preprint
Publicado: 2024
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author An, Congpei
Cai, Mou
author_facet An, Congpei
Cai, Mou
contents This paper explores the incorporation of Tikhonov regularization into the least squares approximation scheme using trigonometric polynomials on the unit circle. This approach encompasses interpolation and hyperinterpolation as specific cases. With the aid of the de la Vallée-Poussin approximation, we derive a uniform error bound and a concrete $L_2$ error bound. These error estimates demonstrate the effectiveness of Tikhonov regularization in the denoising process. A new regularity condition for the selection of regularization parameters is proposed. We investigate three strategies for choosing regularization parameters: Morozov's discrepancy principle, the L-curve, and generalized cross-validation, by explicitly combining these error bounds of the approximating trigonometric polynomial. We show that Morozov's discrepancy principle satisfies the proposed regularity condition, while the other two methods do not. Finally, numerical examples are provided to illustrate how the aforementioned methodologies, when applied with well-chosen parameters, can significantly improve the quality of approximation.
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id arxiv_https___arxiv_org_abs_2403_19927
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Parameter choice strategies for regularized least squares approximation of noisy continuous functions on the unit circle
An, Congpei
Cai, Mou
Numerical Analysis
This paper explores the incorporation of Tikhonov regularization into the least squares approximation scheme using trigonometric polynomials on the unit circle. This approach encompasses interpolation and hyperinterpolation as specific cases. With the aid of the de la Vallée-Poussin approximation, we derive a uniform error bound and a concrete $L_2$ error bound. These error estimates demonstrate the effectiveness of Tikhonov regularization in the denoising process. A new regularity condition for the selection of regularization parameters is proposed. We investigate three strategies for choosing regularization parameters: Morozov's discrepancy principle, the L-curve, and generalized cross-validation, by explicitly combining these error bounds of the approximating trigonometric polynomial. We show that Morozov's discrepancy principle satisfies the proposed regularity condition, while the other two methods do not. Finally, numerical examples are provided to illustrate how the aforementioned methodologies, when applied with well-chosen parameters, can significantly improve the quality of approximation.
title Parameter choice strategies for regularized least squares approximation of noisy continuous functions on the unit circle
topic Numerical Analysis
url https://arxiv.org/abs/2403.19927