Deadman, Edvin and Relton, Samuel (2015) Taylor's Theorem for Matrix Functions with Applications to Condition Number Estimation. [MIMS Preprint]
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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 level1 and level2 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:  MIMS Preprint 

Uncontrolled Keywords:  matrix functions, Taylor series, remainder, condition number, pseudospectrum, Frechet derivative, Kronecker form 
Subjects:  MSC 2010, the AMS's Mathematics Subject Classification > 15 Linear and multilinear algebra; matrix theory MSC 2010, the AMS's Mathematics Subject Classification > 65 Numerical analysis 
Depositing User:  Dr Samuel Relton 
Date Deposited:  09 Oct 2015 
Last Modified:  08 Nov 2017 18:18 
URI:  https://eprints.maths.manchester.ac.uk/id/eprint/2397 
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Taylor's Theorem for Matrix Functions with Applications to Condition Number Estimation. (deposited 28 Apr 2015)
 Taylor's Theorem for Matrix Functions with Applications to Condition Number Estimation. (deposited 09 Oct 2015) [Currently Displayed]
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