<p>This paper presents a unified operator-based framework for deriving and analyzing generalized Householder methods of index <i>p</i> for solving systems of nonlinear equations. Starting from the Newton correction and employing multivariate Taylor expansions, we introduce compact linear operators <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\mathcal {L}_m\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="script">L</mi> <mi>m</mi> </msub> </math></EquationSource> </InlineEquation> that naturally encode the contribution of higher-order Fréchet derivatives along the Newton direction. This formulation leads to a single unified scheme <Equation ID="Equ19"> <EquationSource Format="TEX">\( \left( I - \sum _{m=1}^{p-1} \frac{(-1)^m}{(m+1)!} \mathcal {L}_m \right) \delta = u(x), \)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mfenced close=")" open="("> <mi>I</mi> <mo>-</mo> <munderover> <mo>∑</mo> <mrow> <mi>m</mi> <mo>=</mo> <mn>1</mn> </mrow> <mrow> <mi>p</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mfrac> <msup> <mrow> <mo stretchy="false">(</mo> <mo>-</mo> <mn>1</mn> <mo stretchy="false">)</mo> </mrow> <mi>m</mi> </msup> <mrow> <mo stretchy="false">(</mo> <mi>m</mi> <mo>+</mo> <mn>1</mn> <mo stretchy="false">)</mo> <mo>!</mo> </mrow> </mfrac> <msub> <mi mathvariant="script">L</mi> <mi>m</mi> </msub> </mfenced> <mi>δ</mi> <mo>=</mo> <mi>u</mi> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo stretchy="false">)</mo> </mrow> <mo>,</mo> </mrow> </math></EquationSource> </Equation>where truncation at different values of <i>p</i> systematically recovers Newton’s method (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(p=1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>p</mi> <mo>=</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>), Halley’s method (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(p=2\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>p</mi> <mo>=</mo> <mn>2</mn> </mrow> </math></EquationSource> </InlineEquation>), and higher-order Householder methods. The proposed approach avoids cumbersome tensor notations while clearly demonstrating the error cancellation mechanism responsible for achieving convergence order <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(p+1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>p</mi> <mo>+</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>. The framework is applied to the numerical solution of nonlinear boundary value problems. Numerical experiments confirm that while Newton’s method exhibits a larger basin of attraction, the higher-order Householder methods provide significantly faster asymptotic convergence once the iterate is sufficiently close to the solution. Overall, the operator-theoretic formulation unifies the Householder family, clarifies their theoretical foundation, and offers practical guidance for implementing high-order solvers for nonlinear systems and discretized PDEs.</p>

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Generalized Householder methods of index p for nonlinear systems: derivation, convergence analysis, and applications

  • Varsha Yadav,
  • Anand Shukla,
  • Krishna Kumar,
  • Akhilesh Kumar Singh

摘要

This paper presents a unified operator-based framework for deriving and analyzing generalized Householder methods of index p for solving systems of nonlinear equations. Starting from the Newton correction and employing multivariate Taylor expansions, we introduce compact linear operators \(\mathcal {L}_m\) L m that naturally encode the contribution of higher-order Fréchet derivatives along the Newton direction. This formulation leads to a single unified scheme \( \left( I - \sum _{m=1}^{p-1} \frac{(-1)^m}{(m+1)!} \mathcal {L}_m \right) \delta = u(x), \) I - m = 1 p - 1 ( - 1 ) m ( m + 1 ) ! L m δ = u ( x ) , where truncation at different values of p systematically recovers Newton’s method ( \(p=1\) p = 1 ), Halley’s method ( \(p=2\) p = 2 ), and higher-order Householder methods. The proposed approach avoids cumbersome tensor notations while clearly demonstrating the error cancellation mechanism responsible for achieving convergence order \(p+1\) p + 1 . The framework is applied to the numerical solution of nonlinear boundary value problems. Numerical experiments confirm that while Newton’s method exhibits a larger basin of attraction, the higher-order Householder methods provide significantly faster asymptotic convergence once the iterate is sufficiently close to the solution. Overall, the operator-theoretic formulation unifies the Householder family, clarifies their theoretical foundation, and offers practical guidance for implementing high-order solvers for nonlinear systems and discretized PDEs.