Jordan–Schur Algorithms for Computing the Matrix Exponential

In this paper, two new versions of the Schur algorithm for computing the matrix exponential of an n×n complex matrix A are presented. Instead of the Schur form, these algorithms use the Jordan–Schur form of A. The Jordan–Schur form is found by less computation and it is determined more reliable than...

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Main Author: Petko H. Petkov
Format: Article
Language:English
Published: Hindawi Limited 2023-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/2023/4908185
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author Petko H. Petkov
author_facet Petko H. Petkov
author_sort Petko H. Petkov
collection DOAJ
description In this paper, two new versions of the Schur algorithm for computing the matrix exponential of an n×n complex matrix A are presented. Instead of the Schur form, these algorithms use the Jordan–Schur form of A. The Jordan–Schur form is found by less computation and it is determined more reliable than the reduction to Jordan form since it is obtained using only unitary similarity transformations. In contrast to the known methods, the diagonal blocks of the matrix exponential are obtained by using finite Taylor series. This improves the accuracy and avoids the decisions made about the termination of the series expansion. The off-diagonal blocks of the exponential are determined by modifications of the Schur–Parlett or Schur–Fréchet method, which takes advantage of the Jordan–Schur form of the matrix. The numerical features of the new algorithms are discussed, revealing their advantages and disadvantages in comparison with the other methods for computing the matrix exponential. Computational experiments show that using the new algorithms, the matrix exponential is determined in certain cases with higher accuracy than some widely used methods, however, at the price of an increase in the computational cost which is of order n4. It is shown that the Jordan–Schur algorithms for computing the matrix exponential are appropriate for matrices with multiple eigenvalues and are especially efficient in cases of large Weyr characteristics.
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spelling doaj.art-cd1687f5c0714565b9b1e1ca8de147a12023-03-16T00:00:43ZengHindawi LimitedInternational Journal of Mathematics and Mathematical Sciences1687-04252023-01-01202310.1155/2023/4908185Jordan–Schur Algorithms for Computing the Matrix ExponentialPetko H. Petkov0Department of Engineering SciencesIn this paper, two new versions of the Schur algorithm for computing the matrix exponential of an n×n complex matrix A are presented. Instead of the Schur form, these algorithms use the Jordan–Schur form of A. The Jordan–Schur form is found by less computation and it is determined more reliable than the reduction to Jordan form since it is obtained using only unitary similarity transformations. In contrast to the known methods, the diagonal blocks of the matrix exponential are obtained by using finite Taylor series. This improves the accuracy and avoids the decisions made about the termination of the series expansion. The off-diagonal blocks of the exponential are determined by modifications of the Schur–Parlett or Schur–Fréchet method, which takes advantage of the Jordan–Schur form of the matrix. The numerical features of the new algorithms are discussed, revealing their advantages and disadvantages in comparison with the other methods for computing the matrix exponential. Computational experiments show that using the new algorithms, the matrix exponential is determined in certain cases with higher accuracy than some widely used methods, however, at the price of an increase in the computational cost which is of order n4. It is shown that the Jordan–Schur algorithms for computing the matrix exponential are appropriate for matrices with multiple eigenvalues and are especially efficient in cases of large Weyr characteristics.http://dx.doi.org/10.1155/2023/4908185
spellingShingle Petko H. Petkov
Jordan–Schur Algorithms for Computing the Matrix Exponential
International Journal of Mathematics and Mathematical Sciences
title Jordan–Schur Algorithms for Computing the Matrix Exponential
title_full Jordan–Schur Algorithms for Computing the Matrix Exponential
title_fullStr Jordan–Schur Algorithms for Computing the Matrix Exponential
title_full_unstemmed Jordan–Schur Algorithms for Computing the Matrix Exponential
title_short Jordan–Schur Algorithms for Computing the Matrix Exponential
title_sort jordan schur algorithms for computing the matrix exponential
url http://dx.doi.org/10.1155/2023/4908185
work_keys_str_mv AT petkohpetkov jordanschuralgorithmsforcomputingthematrixexponential