Summing divergent matrix series

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Wang, Rongbiao, Lee, JungHo, Lim, Lek-Heng
Natura: Preprint
Pubblicazione: 2024
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866913603589767168
author Wang, Rongbiao
Lee, JungHo
Lim, Lek-Heng
author_facet Wang, Rongbiao
Lee, JungHo
Lim, Lek-Heng
contents We extend several celebrated methods in classical analysis for summing series of complex numbers to series of complex matrices. These include the summation methods of Abel, Borel, Cesáro, Euler, Lambert, Nörlund, and Mittag-Leffler, which are frequently used to sum scalar series that are divergent in the conventional sense. One feature of our matrix extensions is that they are fully noncommutative generalizations of their scalar counterparts -- not only is the scalar series replaced by a matrix series, positive weights are replaced by positive definite matrix weights, order on $\mathbb{R}$ replaced by Loewner order, exponential function replaced by matrix exponential function, etc. We will establish the regularity of our matrix summation methods, i.e., when applied to a matrix series convergent in the conventional sense, we obtain the same value for the sum. Our second goal is to provide numerical algorithms that work in conjunction with these summation methods. We discuss how the block and mixed-block summation algorithms, the Kahan compensated summation algorithm, may be applied to matrix sums with similar roundoff error bounds. These summation methods and algorithms apply not only to power or Taylor series of matrices but to any general matrix series including matrix Fourier and Dirichlet series. We will demonstrate the utility of these summation methods: establishing a Fejér's theorem and alleviating the Gibbs phenomenon for matrix Fourier series; extending the domains of matrix functions and accurately evaluating them; enhancing the matrix Padé approximation and Schur--Parlett algorithms; and more.
format Preprint
id arxiv_https___arxiv_org_abs_2405_19713
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Summing divergent matrix series
Wang, Rongbiao
Lee, JungHo
Lim, Lek-Heng
Numerical Analysis
Classical Analysis and ODEs
15A16, 40D05, 40G10, 47A56, 65B10, 65F60
We extend several celebrated methods in classical analysis for summing series of complex numbers to series of complex matrices. These include the summation methods of Abel, Borel, Cesáro, Euler, Lambert, Nörlund, and Mittag-Leffler, which are frequently used to sum scalar series that are divergent in the conventional sense. One feature of our matrix extensions is that they are fully noncommutative generalizations of their scalar counterparts -- not only is the scalar series replaced by a matrix series, positive weights are replaced by positive definite matrix weights, order on $\mathbb{R}$ replaced by Loewner order, exponential function replaced by matrix exponential function, etc. We will establish the regularity of our matrix summation methods, i.e., when applied to a matrix series convergent in the conventional sense, we obtain the same value for the sum. Our second goal is to provide numerical algorithms that work in conjunction with these summation methods. We discuss how the block and mixed-block summation algorithms, the Kahan compensated summation algorithm, may be applied to matrix sums with similar roundoff error bounds. These summation methods and algorithms apply not only to power or Taylor series of matrices but to any general matrix series including matrix Fourier and Dirichlet series. We will demonstrate the utility of these summation methods: establishing a Fejér's theorem and alleviating the Gibbs phenomenon for matrix Fourier series; extending the domains of matrix functions and accurately evaluating them; enhancing the matrix Padé approximation and Schur--Parlett algorithms; and more.
title Summing divergent matrix series
topic Numerical Analysis
Classical Analysis and ODEs
15A16, 40D05, 40G10, 47A56, 65B10, 65F60
url https://arxiv.org/abs/2405.19713