Linearization Turns Neural Operators into Function-Valued Gaussian Processes

Fuente: arXiv
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Autores principales: Magnani, Emilia, Pförtner, Marvin, Weber, Tobias, Hennig, Philipp
Formato: Preprint
Publicado: 2024
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author Magnani, Emilia
Pförtner, Marvin
Weber, Tobias
Hennig, Philipp
author_facet Magnani, Emilia
Pförtner, Marvin
Weber, Tobias
Hennig, Philipp
contents Neural operators generalize neural networks to learn mappings between function spaces from data. They are commonly used to learn solution operators of parametric partial differential equations (PDEs) or propagators of time-dependent PDEs. However, to make them useful in high-stakes simulation scenarios, their inherent predictive error must be quantified reliably. We introduce LUNO, a novel framework for approximate Bayesian uncertainty quantification in trained neural operators. Our approach leverages model linearization to push (Gaussian) weight-space uncertainty forward to the neural operator's predictions. We show that this can be interpreted as a probabilistic version of the concept of currying from functional programming, yielding a function-valued (Gaussian) random process belief. Our framework provides a practical yet theoretically sound way to apply existing Bayesian deep learning methods such as the linearized Laplace approximation to neural operators. Just as the underlying neural operator, our approach is resolution-agnostic by design. The method adds minimal prediction overhead, can be applied post-hoc without retraining the network, and scales to large models and datasets. We evaluate these aspects in a case study on Fourier neural operators.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05072
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Linearization Turns Neural Operators into Function-Valued Gaussian Processes
Magnani, Emilia
Pförtner, Marvin
Weber, Tobias
Hennig, Philipp
Machine Learning
G.1.0, I.2.6, G.3, G.1.8
Neural operators generalize neural networks to learn mappings between function spaces from data. They are commonly used to learn solution operators of parametric partial differential equations (PDEs) or propagators of time-dependent PDEs. However, to make them useful in high-stakes simulation scenarios, their inherent predictive error must be quantified reliably. We introduce LUNO, a novel framework for approximate Bayesian uncertainty quantification in trained neural operators. Our approach leverages model linearization to push (Gaussian) weight-space uncertainty forward to the neural operator's predictions. We show that this can be interpreted as a probabilistic version of the concept of currying from functional programming, yielding a function-valued (Gaussian) random process belief. Our framework provides a practical yet theoretically sound way to apply existing Bayesian deep learning methods such as the linearized Laplace approximation to neural operators. Just as the underlying neural operator, our approach is resolution-agnostic by design. The method adds minimal prediction overhead, can be applied post-hoc without retraining the network, and scales to large models and datasets. We evaluate these aspects in a case study on Fourier neural operators.
title Linearization Turns Neural Operators into Function-Valued Gaussian Processes
topic Machine Learning
G.1.0, I.2.6, G.3, G.1.8
url https://arxiv.org/abs/2406.05072