Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain Convergence

In all polynomial zerofinding algorithms, a good convergence requires a very good initial approximation of the exact roots. The objective of the work is to study the conditions for determining the initial approximations for an iterative matrix zerofinding method. The investigation is based on the Ne...

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Main Authors: Saeid Saidanlu, Nor’aini Aris, Ali Abd Rahman
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:Journal of Applied Mathematics
Online Access:http://dx.doi.org/10.1155/2012/167927
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author Saeid Saidanlu
Nor’aini Aris
Ali Abd Rahman
author_facet Saeid Saidanlu
Nor’aini Aris
Ali Abd Rahman
author_sort Saeid Saidanlu
collection DOAJ
description In all polynomial zerofinding algorithms, a good convergence requires a very good initial approximation of the exact roots. The objective of the work is to study the conditions for determining the initial approximations for an iterative matrix zerofinding method. The investigation is based on the Newbery's matrix construction which is similar to Fiedler's construction associated with a characteristic polynomial. To ensure that convergence to both the real and complex roots of polynomials can be attained, three methods are employed. It is found that the initial values for the Fiedler's companion matrix which is supplied by the Schmeisser's method give a better approximation to the solution in comparison to when working on these values using the Schmeisser's construction towards finding the solutions. In addition, empirical results suggest that a good convergence can still be attained when an initial approximation for the polynomial root is selected away from its real value while other approximations should be sufficiently close to their real values. Tables and figures on the errors that resulted from the implementation of the method are also given.
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institution Kabale University
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spelling doaj-art-27527a13ce834b8f9444260ad278dde22025-02-03T01:11:34ZengWileyJournal of Applied Mathematics1110-757X1687-00422012-01-01201210.1155/2012/167927167927Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain ConvergenceSaeid Saidanlu0Nor’aini Aris1Ali Abd Rahman2Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia 81310, Skudai, Johor, MalaysiaDepartment of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia 81310, Skudai, Johor, MalaysiaDepartment of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia 81310, Skudai, Johor, MalaysiaIn all polynomial zerofinding algorithms, a good convergence requires a very good initial approximation of the exact roots. The objective of the work is to study the conditions for determining the initial approximations for an iterative matrix zerofinding method. The investigation is based on the Newbery's matrix construction which is similar to Fiedler's construction associated with a characteristic polynomial. To ensure that convergence to both the real and complex roots of polynomials can be attained, three methods are employed. It is found that the initial values for the Fiedler's companion matrix which is supplied by the Schmeisser's method give a better approximation to the solution in comparison to when working on these values using the Schmeisser's construction towards finding the solutions. In addition, empirical results suggest that a good convergence can still be attained when an initial approximation for the polynomial root is selected away from its real value while other approximations should be sufficiently close to their real values. Tables and figures on the errors that resulted from the implementation of the method are also given.http://dx.doi.org/10.1155/2012/167927
spellingShingle Saeid Saidanlu
Nor’aini Aris
Ali Abd Rahman
Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain Convergence
Journal of Applied Mathematics
title Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain Convergence
title_full Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain Convergence
title_fullStr Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain Convergence
title_full_unstemmed Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain Convergence
title_short Choosing Improved Initial Values for Polynomial Zerofinding in Extended Newbery Method to Obtain Convergence
title_sort choosing improved initial values for polynomial zerofinding in extended newbery method to obtain convergence
url http://dx.doi.org/10.1155/2012/167927
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AT aliabdrahman choosingimprovedinitialvaluesforpolynomialzerofindinginextendednewberymethodtoobtainconvergence