On the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equations

In recent work on the area of approximation methods for the solution of nonlinear differential equations, it has been suggested that the so-called generalized Taylor series approach is equivalent to the homotopy analysis method (HAM). In the present paper, we demonstrate that such a view is only val...

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Main Author: van Gorder, R
Format: Journal article
Published: Springer US 2016
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author van Gorder, R
author_facet van Gorder, R
author_sort van Gorder, R
collection OXFORD
description In recent work on the area of approximation methods for the solution of nonlinear differential equations, it has been suggested that the so-called generalized Taylor series approach is equivalent to the homotopy analysis method (HAM). In the present paper, we demonstrate that such a view is only valid in very special cases, and in general, the HAM is far more robust. In particular, the equivalence is only valid when the solution is represented as a power series in the independent variable. As has been shown many times, alternative basis functions can greatly improve the error properties of homotopy solutions, and when the base functions are not polynomials or power functions, we no longer have that the generalized Taylor series approach is equivalent to the HAM. In particular, the HAM can be used to obtain solutions which are global (defined on the whole domain) rather than local (defined on some restriction of the domain). The HAM can also be used to obtain non-analytic solutions, which by their nature can not be expressed through the generalized Taylor series approach. We demonstrate these properties of the HAM by consideration of an example where the generalizes Taylor series must always have a finite radius of convergence (and hence limited applicability), while the homotopy solution is valid over the entire infinite domain. We then give a second example for which the exact solution is not analytic, and hence, it will not agree with the generalized Taylor series over the domain. Doing so, we show that the generalized Taylor series approach is not as robust as the HAM, and hence, the HAM is more general. Such results have important implications for how iterative solutions are calculated when approximating solutions to nonlinear differential equations.
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spelling oxford-uuid:d31aab08-516c-4fcb-84f3-9e00de20f1f02022-03-27T08:08:59ZOn the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equationsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d31aab08-516c-4fcb-84f3-9e00de20f1f0Symplectic Elements at OxfordSpringer US2016van Gorder, RIn recent work on the area of approximation methods for the solution of nonlinear differential equations, it has been suggested that the so-called generalized Taylor series approach is equivalent to the homotopy analysis method (HAM). In the present paper, we demonstrate that such a view is only valid in very special cases, and in general, the HAM is far more robust. In particular, the equivalence is only valid when the solution is represented as a power series in the independent variable. As has been shown many times, alternative basis functions can greatly improve the error properties of homotopy solutions, and when the base functions are not polynomials or power functions, we no longer have that the generalized Taylor series approach is equivalent to the HAM. In particular, the HAM can be used to obtain solutions which are global (defined on the whole domain) rather than local (defined on some restriction of the domain). The HAM can also be used to obtain non-analytic solutions, which by their nature can not be expressed through the generalized Taylor series approach. We demonstrate these properties of the HAM by consideration of an example where the generalizes Taylor series must always have a finite radius of convergence (and hence limited applicability), while the homotopy solution is valid over the entire infinite domain. We then give a second example for which the exact solution is not analytic, and hence, it will not agree with the generalized Taylor series over the domain. Doing so, we show that the generalized Taylor series approach is not as robust as the HAM, and hence, the HAM is more general. Such results have important implications for how iterative solutions are calculated when approximating solutions to nonlinear differential equations.
spellingShingle van Gorder, R
On the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equations
title On the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equations
title_full On the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equations
title_fullStr On the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equations
title_full_unstemmed On the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equations
title_short On the utility of the homotopy analysis method for non-analytic and global solutions to nonlinear differential equations
title_sort on the utility of the homotopy analysis method for non analytic and global solutions to nonlinear differential equations
work_keys_str_mv AT vangorderr ontheutilityofthehomotopyanalysismethodfornonanalyticandglobalsolutionstononlineardifferentialequations