A posteriori analysis of neural network approximations

Fuente: arXiv
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Autori principali: Führer, Thomas, Rojas, Sergio
Natura: Preprint
Pubblicazione: 2025
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author Führer, Thomas
Rojas, Sergio
author_facet Führer, Thomas
Rojas, Sergio
contents In a general setting, we study a posteriori estimates used in finite element analysis to measure the error between a solution and its approximation. The latter is not necessarily generated by a finite element method. We show that the error is equivalent to the sum of two residuals provided that the underlying variational formulation is well posed. The first contribution is the projection of the residual to a finite-dimensional space and is therefore computable, while the second one can be reliably estimated by a computable upper bound in many practical scenarios. Assuming sufficiently accurate quadrature, our findings can be used to estimate the error of, e.g., neural network outputs. Two important applications can be considered during optimization: first, the estimators are used to monitor the error in each solver step, or, second, the two estimators are included in the loss functional, and therefore provide control over the error. As a model problem, we consider a second-order elliptic partial differential equation and discuss different variational formulations thereof, including several options to include boundary conditions in the estimators. Various numerical experiments are presented to validate our findings.
format Preprint
id arxiv_https___arxiv_org_abs_2507_06017
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A posteriori analysis of neural network approximations
Führer, Thomas
Rojas, Sergio
Numerical Analysis
65N15, 65M60, 65M75
In a general setting, we study a posteriori estimates used in finite element analysis to measure the error between a solution and its approximation. The latter is not necessarily generated by a finite element method. We show that the error is equivalent to the sum of two residuals provided that the underlying variational formulation is well posed. The first contribution is the projection of the residual to a finite-dimensional space and is therefore computable, while the second one can be reliably estimated by a computable upper bound in many practical scenarios. Assuming sufficiently accurate quadrature, our findings can be used to estimate the error of, e.g., neural network outputs. Two important applications can be considered during optimization: first, the estimators are used to monitor the error in each solver step, or, second, the two estimators are included in the loss functional, and therefore provide control over the error. As a model problem, we consider a second-order elliptic partial differential equation and discuss different variational formulations thereof, including several options to include boundary conditions in the estimators. Various numerical experiments are presented to validate our findings.
title A posteriori analysis of neural network approximations
topic Numerical Analysis
65N15, 65M60, 65M75
url https://arxiv.org/abs/2507.06017