An iterative method for the solution of Laplace-like equations in high and very high space dimensions

Fuente: arXiv
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Autor principal: Yserentant, Harry
Formato: Preprint
Publicado: 2024
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author Yserentant, Harry
author_facet Yserentant, Harry
contents This paper deals with the equation $-Δu+μu=f$ on high-dimensional spaces $\mathbb{R}^m$, where the right-hand side $f(x)=F(Tx)$ is composed of a separable function $F$ with an integrable Fourier transform on a space of a dimension $n>m$ and a linear mapping given by a matrix $T$ of full rank and $μ\geq 0$ is a constant. For example, the right-hand side can explicitly depend on differences $x_i-x_j$ of components of $x$. We show that the solution of this equation can be expanded into sums of functions of the same structure and develop in this framework an equally simple and fast iterative method for its computation. The method is based on the observation that in almost all cases and for large problem classes the expression $\|T^ty\|^2$ deviates on the unit sphere $\|y\|=1$ the less from its mean value the higher the dimension $m$ is, a concentration of measure effect. The higher the dimension $m$, the faster the iteration converges.
format Preprint
id arxiv_https___arxiv_org_abs_2403_00682
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An iterative method for the solution of Laplace-like equations in high and very high space dimensions
Yserentant, Harry
Numerical Analysis
41A46, 41A63, 65D40, 65N12
This paper deals with the equation $-Δu+μu=f$ on high-dimensional spaces $\mathbb{R}^m$, where the right-hand side $f(x)=F(Tx)$ is composed of a separable function $F$ with an integrable Fourier transform on a space of a dimension $n>m$ and a linear mapping given by a matrix $T$ of full rank and $μ\geq 0$ is a constant. For example, the right-hand side can explicitly depend on differences $x_i-x_j$ of components of $x$. We show that the solution of this equation can be expanded into sums of functions of the same structure and develop in this framework an equally simple and fast iterative method for its computation. The method is based on the observation that in almost all cases and for large problem classes the expression $\|T^ty\|^2$ deviates on the unit sphere $\|y\|=1$ the less from its mean value the higher the dimension $m$ is, a concentration of measure effect. The higher the dimension $m$, the faster the iteration converges.
title An iterative method for the solution of Laplace-like equations in high and very high space dimensions
topic Numerical Analysis
41A46, 41A63, 65D40, 65N12
url https://arxiv.org/abs/2403.00682