Computing the common zeros of two bivariate functions via Bezout resultants

The common zeros of two bivariate functions can be computed by finding the common zeros of their polynomial interpolants expressed in a tensor Chebyshev basis. From here we develop a bivariate rootfinding algorithm based on the hidden variable resultant method and Bezout matrices with polynomial ent...

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Main Authors: Nakatsukasa, Y, Noferini, V, Townsend, A
Format: Report
Published: Unspecified 2013
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author Nakatsukasa, Y
Noferini, V
Townsend, A
author_facet Nakatsukasa, Y
Noferini, V
Townsend, A
author_sort Nakatsukasa, Y
collection OXFORD
description The common zeros of two bivariate functions can be computed by finding the common zeros of their polynomial interpolants expressed in a tensor Chebyshev basis. From here we develop a bivariate rootfinding algorithm based on the hidden variable resultant method and Bezout matrices with polynomial entries. Using techniques including domain subdivision, Bezoutian regularization and local refinement we are able to reliably and accurately compute the simple common zeros of two smooth functions with polynomial interpolants of very high degree ($\ge$ 1000). We analyze the resultant method and its conditioning by noting that the Bezout matrices are matrix polynomials. Our robust algorithm is implemented in the roots command in Chebfun2, a software package written in object-oriented MATLAB for computing with bivariate functions.
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spelling oxford-uuid:5b6f5fad-c3e6-4485-866b-ec13c29603532022-03-26T17:22:02ZComputing the common zeros of two bivariate functions via Bezout resultants Reporthttp://purl.org/coar/resource_type/c_93fcuuid:5b6f5fad-c3e6-4485-866b-ec13c2960353Mathematical Institute - ePrintsUnspecified2013Nakatsukasa, YNoferini, VTownsend, AThe common zeros of two bivariate functions can be computed by finding the common zeros of their polynomial interpolants expressed in a tensor Chebyshev basis. From here we develop a bivariate rootfinding algorithm based on the hidden variable resultant method and Bezout matrices with polynomial entries. Using techniques including domain subdivision, Bezoutian regularization and local refinement we are able to reliably and accurately compute the simple common zeros of two smooth functions with polynomial interpolants of very high degree ($\ge$ 1000). We analyze the resultant method and its conditioning by noting that the Bezout matrices are matrix polynomials. Our robust algorithm is implemented in the roots command in Chebfun2, a software package written in object-oriented MATLAB for computing with bivariate functions.
spellingShingle Nakatsukasa, Y
Noferini, V
Townsend, A
Computing the common zeros of two bivariate functions via Bezout resultants
title Computing the common zeros of two bivariate functions via Bezout resultants
title_full Computing the common zeros of two bivariate functions via Bezout resultants
title_fullStr Computing the common zeros of two bivariate functions via Bezout resultants
title_full_unstemmed Computing the common zeros of two bivariate functions via Bezout resultants
title_short Computing the common zeros of two bivariate functions via Bezout resultants
title_sort computing the common zeros of two bivariate functions via bezout resultants
work_keys_str_mv AT nakatsukasay computingthecommonzerosoftwobivariatefunctionsviabezoutresultants
AT noferiniv computingthecommonzerosoftwobivariatefunctionsviabezoutresultants
AT townsenda computingthecommonzerosoftwobivariatefunctionsviabezoutresultants