Regularized Random Fourier Features and Finite Element Reconstruction for Operator Learning in Sobolev Space

Fuente: arXiv
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Main Authors: Yu, Xinyue, Schaeffer, Hayden
Format: Preprint
Published: 2025
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author Yu, Xinyue
Schaeffer, Hayden
author_facet Yu, Xinyue
Schaeffer, Hayden
contents Operator learning is a data-driven approximation of mappings between infinite-dimensional function spaces, such as the solution operators of partial differential equations. Kernel-based operator learning can offer accurate, theoretically justified approximations that require less training than standard methods. However, they can become computationally prohibitive for large training sets and can be sensitive to noise. We propose a regularized random Fourier feature (RRFF) approach, coupled with a finite element reconstruction map (RRFF-FEM), for learning operators from noisy data. The method uses random features drawn from multivariate Student's $t$ distributions, together with frequency-weighted Tikhonov regularization that suppresses high-frequency noise. We establish high-probability bounds on the extreme singular values of the associated random feature matrix and show that when the number of features $N$ scales like $m \log m$ with the number of training samples $m$, the system is well-conditioned, which yields estimation and generalization guarantees. Detailed numerical experiments on benchmark PDE problems, including advection, Burgers', Darcy flow, Helmholtz, Navier-Stokes, and structural mechanics, demonstrate that RRFF and RRFF-FEM are robust to noise and achieve improved performance with reduced training time compared to the unregularized random feature model, while maintaining competitive accuracy relative to kernel and neural operator tests.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17884
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Regularized Random Fourier Features and Finite Element Reconstruction for Operator Learning in Sobolev Space
Yu, Xinyue
Schaeffer, Hayden
Machine Learning
Numerical Analysis
68W20, 62G05, 65M32, 65N21, 65D05
Operator learning is a data-driven approximation of mappings between infinite-dimensional function spaces, such as the solution operators of partial differential equations. Kernel-based operator learning can offer accurate, theoretically justified approximations that require less training than standard methods. However, they can become computationally prohibitive for large training sets and can be sensitive to noise. We propose a regularized random Fourier feature (RRFF) approach, coupled with a finite element reconstruction map (RRFF-FEM), for learning operators from noisy data. The method uses random features drawn from multivariate Student's $t$ distributions, together with frequency-weighted Tikhonov regularization that suppresses high-frequency noise. We establish high-probability bounds on the extreme singular values of the associated random feature matrix and show that when the number of features $N$ scales like $m \log m$ with the number of training samples $m$, the system is well-conditioned, which yields estimation and generalization guarantees. Detailed numerical experiments on benchmark PDE problems, including advection, Burgers', Darcy flow, Helmholtz, Navier-Stokes, and structural mechanics, demonstrate that RRFF and RRFF-FEM are robust to noise and achieve improved performance with reduced training time compared to the unregularized random feature model, while maintaining competitive accuracy relative to kernel and neural operator tests.
title Regularized Random Fourier Features and Finite Element Reconstruction for Operator Learning in Sobolev Space
topic Machine Learning
Numerical Analysis
68W20, 62G05, 65M32, 65N21, 65D05
url https://arxiv.org/abs/2512.17884