Adaptive Randomized Neural Networks with Locally Activation Function: Theory and Algorithm for Solving PDEs

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Hauptverfasser: Bi, Ran, Deng, Weibing
Format: Preprint
Veröffentlicht: 2026
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author Bi, Ran
Deng, Weibing
author_facet Bi, Ran
Deng, Weibing
contents This paper establishes an approximation theorem for randomized neural networks (RaNNs) whose hidden-layer parameters are uniformly sampled from a prescribed bounded domain. Our analysis shows that, for RaNNs of the form $\mathop{\sum}_i W_i σ(A_i, b_i)$, the size of the sampling domain required to achieve optimal approximation is intrinsically linked to the smoothness of the target function and the number of neurons. Motivated by this theoretical insight, we integrate a partition of unity (PoU) with RaNNs to develop an adaptive physics-informed randomized neural network (PIRaNN) method for solving partial differential equations with limited local regularity. The proposed adaptive strategy refines the PoU based on a posteriori error indicators, enabling the network to efficiently capture localized solution features. Numerical experiments validate the theoretical results and demonstrate the strong approximation capabilities of RaNNs, confirming the effectiveness of the adaptive PIRaNN method on a range of benchmark problems.
format Preprint
id arxiv_https___arxiv_org_abs_2604_08869
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Adaptive Randomized Neural Networks with Locally Activation Function: Theory and Algorithm for Solving PDEs
Bi, Ran
Deng, Weibing
Numerical Analysis
68T07, 65N50, 41A25
This paper establishes an approximation theorem for randomized neural networks (RaNNs) whose hidden-layer parameters are uniformly sampled from a prescribed bounded domain. Our analysis shows that, for RaNNs of the form $\mathop{\sum}_i W_i σ(A_i, b_i)$, the size of the sampling domain required to achieve optimal approximation is intrinsically linked to the smoothness of the target function and the number of neurons. Motivated by this theoretical insight, we integrate a partition of unity (PoU) with RaNNs to develop an adaptive physics-informed randomized neural network (PIRaNN) method for solving partial differential equations with limited local regularity. The proposed adaptive strategy refines the PoU based on a posteriori error indicators, enabling the network to efficiently capture localized solution features. Numerical experiments validate the theoretical results and demonstrate the strong approximation capabilities of RaNNs, confirming the effectiveness of the adaptive PIRaNN method on a range of benchmark problems.
title Adaptive Randomized Neural Networks with Locally Activation Function: Theory and Algorithm for Solving PDEs
topic Numerical Analysis
68T07, 65N50, 41A25
url https://arxiv.org/abs/2604.08869