## 2015.27: Taylor's Theorem for Matrix Functions with Applications to Condition Number Estimation

2015.27:
Edvin Deadman and Samuel Relton
(2016)
*Taylor's Theorem for Matrix Functions with Applications to Condition Number Estimation.*
Linear Algebra and its Applications, 504 (2015.27).
pp. 354-371.
ISSN 0024-3795

*This is the latest version of this eprint.*

Full text available as:

PDF (Final Published Article) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader 536 Kb |

DOI: 10.1016/j.laa.2016.04.010

## Abstract

We derive an explicit formula for the remainder term of a Taylor polynomial of a matrix function. This formula generalizes a known result for the remainder of the Taylor polynomial for an analytic function of a complex scalar. We investigate some consequences of this result, which culminate in new upper bounds for the level-1 and level-2 condition numbers of a matrix function in terms of the pseudospectrum of the matrix. Numerical experiments show that, although the bounds can be pessimistic, they can be computed much faster than the standard methods. This makes the upper bounds ideal for a quick estimation of the condition number whilst a more accurate (and expensive) method can be used if further accuracy is required. They are also easily applicable to more complicated matrix functions for which no specialized condition number estimators are currently available.

Item Type: | Article |
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Uncontrolled Keywords: | matrix functions, Taylor series, remainder, condition number, pseudospectrum, Frechet derivative, Kronecker form |

Subjects: | MSC 2000 > 15 Linear and multilinear algebra; matrix theory MSC 2000 > 65 Numerical analysis |

MIMS number: | 2015.27 |

Deposited By: | Dr Samuel Relton |

Deposited On: | 31 May 2016 |

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- Taylor's Theorem for Matrix Functions with Applications to Condition Number Estimation (deposited 31 May 2016)
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