Neural Operators with Localized Integral and Differential Kernels

Fuente: arXiv
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Auteurs principaux: Liu-Schiaffini, Miguel, Berner, Julius, Bonev, Boris, Kurth, Thorsten, Azizzadenesheli, Kamyar, Anandkumar, Anima
Format: Preprint
Publié: 2024
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author Liu-Schiaffini, Miguel
Berner, Julius
Bonev, Boris
Kurth, Thorsten
Azizzadenesheli, Kamyar
Anandkumar, Anima
author_facet Liu-Schiaffini, Miguel
Berner, Julius
Bonev, Boris
Kurth, Thorsten
Azizzadenesheli, Kamyar
Anandkumar, Anima
contents Neural operators learn mappings between function spaces, which is practical for learning solution operators of PDEs and other scientific modeling applications. Among them, the Fourier neural operator (FNO) is a popular architecture that performs global convolutions in the Fourier space. However, such global operations are often prone to over-smoothing and may fail to capture local details. In contrast, convolutional neural networks (CNN) can capture local features but are limited to training and inference at a single resolution. In this work, we present a principled approach to operator learning that can capture local features under two frameworks by learning differential operators and integral operators with locally supported kernels. Specifically, inspired by stencil methods, we prove that we obtain differential operators under an appropriate scaling of the kernel values of CNNs. To obtain local integral operators, we utilize suitable basis representations for the kernels based on discrete-continuous convolutions. Both these approaches preserve the properties of operator learning and, hence, the ability to predict at any resolution. Adding our layers to FNOs significantly improves their performance, reducing the relative L2-error by 34-72% in our experiments, which include a turbulent 2D Navier-Stokes and the spherical shallow water equations.
format Preprint
id arxiv_https___arxiv_org_abs_2402_16845
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Neural Operators with Localized Integral and Differential Kernels
Liu-Schiaffini, Miguel
Berner, Julius
Bonev, Boris
Kurth, Thorsten
Azizzadenesheli, Kamyar
Anandkumar, Anima
Machine Learning
Artificial Intelligence
Numerical Analysis
Neural operators learn mappings between function spaces, which is practical for learning solution operators of PDEs and other scientific modeling applications. Among them, the Fourier neural operator (FNO) is a popular architecture that performs global convolutions in the Fourier space. However, such global operations are often prone to over-smoothing and may fail to capture local details. In contrast, convolutional neural networks (CNN) can capture local features but are limited to training and inference at a single resolution. In this work, we present a principled approach to operator learning that can capture local features under two frameworks by learning differential operators and integral operators with locally supported kernels. Specifically, inspired by stencil methods, we prove that we obtain differential operators under an appropriate scaling of the kernel values of CNNs. To obtain local integral operators, we utilize suitable basis representations for the kernels based on discrete-continuous convolutions. Both these approaches preserve the properties of operator learning and, hence, the ability to predict at any resolution. Adding our layers to FNOs significantly improves their performance, reducing the relative L2-error by 34-72% in our experiments, which include a turbulent 2D Navier-Stokes and the spherical shallow water equations.
title Neural Operators with Localized Integral and Differential Kernels
topic Machine Learning
Artificial Intelligence
Numerical Analysis
url https://arxiv.org/abs/2402.16845