arXiv:2605.12965cs.LGcs.NA2026-05

U-HNO用自适应路由机制,精准处理偏微分方程中的平滑与突变共存问题。

U-HNO: A U-shaped Hybrid Neural Operator with Sparse-Point Adaptive Routing for Non-stationary PDE Dynamics

论文配图:U-HNO: A U-shaped Hybrid Neural Operator with Sparse-Point Adaptive Routing for Non-stationary PDE Dynamics
图 1 · 摘自论文原文
  • 按局部特征强度动态选择全局傅里叶或局部多尺度计算,实现自适应融合
  • 在13个基准测试中多数任务取得最佳滚动精度,尤其擅长处理尖锐局部特征
  • 适合需要高精度模拟复杂非稳态物理现象的研究者使用

许多偏微分方程的解在同一轨迹中同时包含平滑的大范围传输和局部尖锐特征:如激波前沿、薄界面和高频率集中区域叠加在缓慢变化的背景上。这给神经算子带来挑战:基于傅里叶的架构虽高效融合非局部交互,但难以解析局部非光滑特征;而空间局部架构虽能捕捉细节,却牺牲长程传播与滚动稳定性。现有混合算子采用固定均匀融合,无法缓解这一矛盾。本文提出U-HNO,一种具有稀疏点自适应路由(SPAR)的U形混合神经算子:在每个空间位置,通过像素级硬掩码决定全局傅里叶分支或局部多尺度高斯分支主导,且稀疏率由路由信号的局部对比度决定,使平滑区与激波对齐区获得不同比例的全局与局部计算。SPAR嵌入分层编码器-瓶颈-解码器结构,各分辨率下均运行双分支与门控机制。训练结合点监督、有限差分H^1梯度项及带状谱一致性正则化。在涵盖1D Burgers、Kuramoto-Sivashinsky、KdV、2D输运、Allen-Cahn、Navier-Stokes、Darcy流以及3D跨音速可压缩Navier-Stokes的PDEBench多个基准上,U-HNO在相对L^2和H^1指标上多数任务达到当前最优,尤其在以尖锐局部特征为主的任务中提升显著。消融实验表明移除任一组件均导致滚动误差明显上升。

原文摘要 · Abstract (English)

Solutions to many partial differential equations (PDEs) display coexisting smooth global transport and localized sharp features within a single trajectory: shock fronts, thin interfaces, and concentrated high-frequency content sit on top of slowly varying backgrounds. This poses a challenge for neural operators: Fourier-based architectures mix nonlocal interactions efficiently but tend to under-resolve localized non-smooth features, whereas spatially local architectures recover fine detail at the cost of long-range propagation and rollout stability. Existing hybrid operators paper over this tension with a fixed, spatially uniform fusion that forces the same trade-off everywhere. We propose U-HNO, a U-shaped hybrid neural operator whose central design is Sparse-Point Adaptive Routing (SPAR): at every spatial location, a per-pixel hard mask selects whether the global Fourier branch or the local multi-scale Gaussian branch should dominate, and the sparsity ratio is a function of the local contrast of the routing signal, so smooth and shock-aligned regions receive different mixtures of global and local computation. SPAR is embedded in a hierarchical encoder-bottleneck-decoder backbone with skip connections so that the dual branches and the gate operate at every resolution. Training combines pointwise supervision with a finite-difference H^1 gradient term and a band-wise spectral consistency regularizer. Across benchmarks spanning 1D Burgers, Kuramoto-Sivashinsky, KdV, 2D advection, Allen-Cahn, Navier-Stokes, Darcy flow, and 3D transonic compressible Navier-Stokes from PDEBench, U-HNO achieves state-of-the-art rollout accuracy on the majority of tasks in both relative L^2 and H^1 metrics, with the largest gains on problems dominated by sharp localized features. Ablations show that removing any single component substantially degrades rollout error.

偏微分方程神经算子自适应路由物理模拟

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