The Isogeometric Fast Fourier-based Diagonalization method

Fuente: arXiv
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Main Authors: Montardini, Monica, Takacs, Stefan, Tani, Mattia
Format: Preprint
Published: 2025
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author Montardini, Monica
Takacs, Stefan
Tani, Mattia
author_facet Montardini, Monica
Takacs, Stefan
Tani, Mattia
contents The construction of robust solvers for linear systems obtained from the discretization of partial differential equations using Isogeometric Analysis is challenging since the condition number of the system matrix not only grows with the reciprocal square of the grid size (for second order problems), but also exponentially with the spline degree. The Fast Diagonalization method allows the construction of a preconditioner that is robust both in grid size and spline degree. Although this method is efficient in practice, its computational complexity is superlinear in the number of degrees of freedom. In this work, we construct a variant of the Fast Diagonalization method that can exploit the Fast Fourier Transformation. Note that, because of boundary effects, a Fourier Transformation cannot diagonalize the overall problem. We circumvent this issue using a stable splitting of the spline space. The resulting preconditioner is still robust with respect to the grid size and spline degree and can be realized with a computational complexity that grows almost linearly with the number of degrees of freedom.
format Preprint
id arxiv_https___arxiv_org_abs_2512_20269
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Isogeometric Fast Fourier-based Diagonalization method
Montardini, Monica
Takacs, Stefan
Tani, Mattia
Numerical Analysis
The construction of robust solvers for linear systems obtained from the discretization of partial differential equations using Isogeometric Analysis is challenging since the condition number of the system matrix not only grows with the reciprocal square of the grid size (for second order problems), but also exponentially with the spline degree. The Fast Diagonalization method allows the construction of a preconditioner that is robust both in grid size and spline degree. Although this method is efficient in practice, its computational complexity is superlinear in the number of degrees of freedom. In this work, we construct a variant of the Fast Diagonalization method that can exploit the Fast Fourier Transformation. Note that, because of boundary effects, a Fourier Transformation cannot diagonalize the overall problem. We circumvent this issue using a stable splitting of the spline space. The resulting preconditioner is still robust with respect to the grid size and spline degree and can be realized with a computational complexity that grows almost linearly with the number of degrees of freedom.
title The Isogeometric Fast Fourier-based Diagonalization method
topic Numerical Analysis
url https://arxiv.org/abs/2512.20269