用可学习的局部卷积代替全局操作,让神经PDE求解器更快更准。
PDE Solvers Should Be Local: Fast, Stable Rollouts with Learned Local Stencils
- 用可学习的局部卷积核和显式时间步进替代全局混合机制
- 在6个基准上误差降低44%,速度提升2倍,长期滚动推演更稳定
- 适合需要高精度局部动态建模的科学计算场景
求解偏微分方程(PDE)的神经算子模型常依赖谱卷积或注意力等全局混合机制,易平滑尖锐局部动态并带来高计算开销。我们提出FINO,一种受有限差分启发的神经架构,严格保证局部性同时保留多尺度表达能力。FINO将固定有限差分模板系数替换为可学习卷积核,并通过可学习的显式时间步进演化状态。核心局部算子模块结合微分模板层、门控掩码与线性融合步骤,构建自适应的导数类局部特征并向前传播。嵌入编码器-解码器结构与瓶颈设计,能捕捉细粒度局部结构且保持可解释性。我们建立了:(i) 一步近似误差与在Lipschitz条件下稳定长时滚动推演之间的组合误差界;(ii) 离散时间步进式PDE动力学的通用逼近定理。(iii) 在六个基准和一个气候建模任务中,FINO误差最高降低44%,速度提升约2倍,证明严格局部性与可学习时间步进能为神经PDE求解器提供准确且可扩展的基础。
原文摘要 · Abstract (English)
Neural operator models for solving partial differential equations (PDEs) often rely on global mixing mechanisms-such as spectral convolutions or attention-which tend to oversmooth sharp local dynamics and introduce high computational cost. We present FINO, a finite-difference-inspired neural architecture that enforces strict locality while retaining multiscale representational power. FINO replaces fixed finite-difference stencil coefficients with learnable convolutional kernels and evolves states via an explicit, learnable time-stepping scheme. A central Local Operator Block leverage a differential stencil layer, a gating mask, and a linear fuse step to construct adaptive derivative-like local features that propagate forward in time. Embedded in an encoder-decoder with a bottleneck, FINO captures fine-grained local structures while preserving interpretability. We establish (i) a composition error bound linking one-step approximation error to stable long-horizon rollouts under a Lipschitz condition, and (ii) a universal approximation theorem for discrete time-stepped PDE dynamics. (iii) Across six benchmarks and a climate modelling task, FINO achieves up to 44\% lower error and up to around 2\times speedups over state-of-the-art operator-learning baselines, demonstrating that strict locality with learnable time-stepping yields an accurate and scalable foundation for neural PDE solvers.
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