arXiv:2604.13830math.NAcs.LG2026-04

用随机神经网络高效求解非局部积分微分方程,降低计算成本。

Randomized Neural Networks for Integro-Differential Equations with Application to Neutron Transport

  • 通过随机固定隐层参数,将训练转为凸优化问题。
  • 在中子输运测试中,精度相当但训练开销显著更低。
  • 适合高维非局部问题,对超参数不敏感,稳定高效。

积分微分方程广泛存在于运输、动理学理论、辐射传输和多物理场建模中,其非局部积分算子在相空间内耦合解。传统确定性离散常导致密集耦合块,增加计算与内存开销;而物理信息神经网络则面临非凸训练昂贵且对超参数敏感的问题。本文提出随机神经网络(RaNNs),作为线性积分微分方程的无网格配点框架。由于RaNN近似通过全局支持的随机特征天然稠密,非局部积分算子不会破坏稀疏性,同时解仍可用较少可训练自由度表示。通过随机固定隐藏层参数并仅求解线性输出权重,训练过程退化为输出系数的凸最小二乘问题,实现稳定高效的优化。以稳态中子输运方程为例,该模型具有散射积分和多种边界条件,属于高维线性积分微分问题。大量数值实验表明,在给定测试设置下,RaNN方法达到竞争性精度,且训练成本远低于所选神经网络与确定性基线,凸显其在非局部线性算子数值模拟中的鲁棒性与高效性。

原文摘要 · Abstract (English)

Integro-differential equations arise in a wide range of applications, including transport, kinetic theory, radiative transfer, and multiphysics modeling, where nonlocal integral operators couple the solution across phase space. Such nonlocality often introduces dense coupling blocks in deterministic discretizations, leading to increased computational cost and memory usage, while physics-informed neural networks may suffer from expensive nonconvex training and sensitivity to hyperparameter choices. In this work, we present randomized neural networks (RaNNs) as a mesh-free collocation framework for linear integro-differential equations. Because the RaNN approximation is intrinsically dense through globally supported random features, the nonlocal integral operator does not introduce an additional loss of sparsity, while the approximate solution can still be represented with relatively few trainable degrees of freedom. By randomly fixing the hidden-layer parameters and solving only for the linear output weights, the training procedure reduces to a convex least-squares problem in the output coefficients, enabling stable and efficient optimization. As a representative application, we apply the proposed framework to the steady neutron transport equation, a high-dimensional linear integro-differential model featuring scattering integrals and diverse boundary conditions. Extensive numerical experiments demonstrate that, in the reported test settings, the RaNN approach achieves competitive accuracy while incurring substantially lower training cost than the selected neural and deterministic baselines, highlighting RaNNs as a robust and efficient alternative for the numerical simulation of nonlocal linear operators.

神经网络积分微分方程中子输运随机逼近

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