arXiv:2606.27140cs.LG2026-06

用张量神经网络求解分数阶偏微分方程,精度显著优于现有方法。

fTNN: a tensor neural network for fractional PDEs

论文配图:fTNN: a tensor neural network for fractional PDEs
图 1 · 摘自论文原文
  • 基于几何自适应积分分解,将分数阶拉普拉斯算子拆分为近场、远场三部分。
  • 在边界奇异性强时仍保持高精度,长时模拟误差更小。
  • 适合求解含强边界奇性的分数阶方程,尤其适用于物理建模场景。

我们提出fTNN,一种用于有界域上分数阶拉普拉斯问题的确定性张量神经网络子空间方法,以分数阶泊松方程和时变分数阶对流-扩散方程为典型代表。方法采用几何自适应积分分解,引入空间依赖的近场半径,将分数阶拉普拉斯算子分解为奇异近场、规则内部远场和解析外部远场三部分。奇异径向积分采用Gauss-Jacobi求积,规则径向积分采用Gauss求积,角向变量采用确定性角向求积,构建完全确定的分数阶拉普拉斯算子积分框架。为精确处理低正则性解及其损失函数,构造了包含显式边界特征的边界奇异性感知试函数,并提出两种自动选择主导指数及从分数阶算子或其与源项共同诱导的奇异性结构中评估损失函数的策略。对于时变分数阶偏微分方程,设计了时空可分离的神经网络,将时空残差分解为低维时间与空间积分之和,并结合交替神经网络子空间优化策略实现高效训练。数值实验表明,该框架在测试基准上达到高精度,显著优于现有的fPINN和蒙特卡洛基线,尤其在边界奇性强和长时间模拟下表现突出。

原文摘要 · Abstract (English)

We develop the fTNN, a deterministic tensor neural network subspace method for problems involving the fractional Laplacian on bounded domains, taking the fractional Poisson equation and time-dependent fractional advection-diffusion equation as typical representatives. The work employs a geometry-adapted integration split featuring a spatially dependent near-field radius, which decomposes the fractional Laplacian into three contributions: a singular near field, a regular interior far field, and an analytical exterior far field. Then the singular radial integrals are treated by Gauss-Jacobi quadrature, the regular radial integrals by Gauss quadrature, and the angular variables by deterministic angular quadrature, yielding a fully deterministic integration framework of the fractional Laplacian operator. To accurately resolve low-regularity solutions and the associated loss functional, we construct boundary-singularity-aware trial functions enriched with explicit boundary features, and propose two strategies for automatically selecting the leading exponent and evaluating the loss function from the singularity structure induced by the fractional operator, or jointly by the fractional operator and the source term. For time-dependent fractional PDEs, we design a spatiotemporally separable neural network that factorizes the time-space residual into a sum of low-dimensional temporal and spatial integrals, and we integrate this representation with an alternating neural network subspace optimization strategy for efficient training. Numerical experiments show that the proposed framework attains high accuracy on the tested benchmarks and improves substantially over existing fPINN and Monte Carlo baselines, particularly for problems with strong boundary singularities and long-time simulations.

分数阶方程神经网络张量方法

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