通过物理与对称性约束,显著提升神经偏微分方程代理模型的泛化与精度。
Geometric and Physical Constraints Synergistically Enhance Neural PDE Surrogates
- 设计适配交错网格的输入输出层,融合物理定律与对称性先验。
- 双约束模型在两类复杂问题上均超越基线,误差更低、泛化更强。
- 适合需要高精度与鲁棒性的流体模拟场景,如海洋流预测。
神经偏微分方程代理模型能改善经典求解器的成本-精度权衡,但对新初值泛化能力差且随时间累积误差。物理与对称性约束有望弥补此差距,但现有方法不兼容计算流体中常用的交错网格。本文提出新型输入输出层,使其在交错网格上尊重物理规律与对称性,并首次系统研究这些约束单独及联合使用对代理模型精度的影响。聚焦浅水方程闭边界与不可压缩湍流衰减两个难题,相比强基线,对称性与物理约束在任务、架构、自回归步数、精度指标和网络规模上均持续提升性能。对称性比物理约束更有效,但双约束模型表现最佳,甚至优于带数据增强或前推训练的基线,自身也受益于前推技巧。双重约束模型对训练数据外的初值与时长更具泛化能力,且更准确预测真实海洋洋流。
原文摘要 · Abstract (English)
Neural PDE surrogates can improve the cost-accuracy tradeoff of classical solvers, but often generalize poorly to new initial conditions and accumulate errors over time. Physical and symmetry constraints have shown promise in closing this performance gap, but existing techniques for imposing these inductive biases are incompatible with the staggered grids commonly used in computational fluid dynamics. Here we introduce novel input and output layers that respect physical laws and symmetries on the staggered grids, and for the first time systematically investigate how these constraints, individually and in combination, affect the accuracy of PDE surrogates. We focus on two challenging problems: shallow water equations with closed boundaries and decaying incompressible turbulence. Compared to strong baselines, symmetries and physical constraints consistently improve performance across tasks, architectures, autoregressive prediction steps, accuracy measures, and network sizes. Symmetries are more effective than physical constraints, but surrogates with both performed best, even compared to baselines with data augmentation or pushforward training, while themselves benefiting from the pushforward trick. Doubly-constrained surrogates also generalize better to initial conditions and durations beyond the range of the training data, and more accurately predict real-world ocean currents.
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