arXiv:2512.05297cs.LGcs.AI2025-12被引 9

CFO让神经算子直接学连续时间的偏微分方程,不依赖固定时间步长。

CFO: Learning Continuous-Time PDE Dynamics via Flow-Matched Neural Operators

  • 用流匹配直接学习PDE右端项,避免反向传播求解器
  • 仅用25%不规则采样数据,误差比传统方法低87%
  • 支持任意时间分辨率查询和逆时间推理,适合长时序模拟

针对时间依赖偏微分方程的神经算子代理模型,传统自回归预测在长序列上累积误差且需均匀时间离散。本文提出连续流算子(CFO),无需标准连续方法(如神经ODE)的计算负担,核心思想是将流匹配重用于直接学习PDE右端项,无需通过求解器反向传播。CFO对轨迹数据拟合时间样条,在节点处使用有限差分估计时间导数,构建逼近真实PDE动力学的速度概率路径。再通过流匹配训练神经算子以预测这些解析速度场。该方法天然具备时间分辨率不变性:训练可接受任意非均匀时间网格的数据,推理时可通过常微分方程积分在任意时间分辨率下查询解。在四个基准任务(Lorenz、1D Burgers、2D扩散-反应、2D浅水)上,CFO展现出优越的长期稳定性与显著的数据效率。仅用25%不规则子采样时间点训练,其相对误差较自回归基线降低高达87%。尽管推理需数值积分,但仅需基线50%的函数评估次数,同时唯一支持逆时间推理与任意时间查询。

原文摘要 · Abstract (English)

Neural operator surrogates for time-dependent partial differential equations (PDEs) conventionally employ autoregressive prediction schemes, which accumulate error over long rollouts and require uniform temporal discretization. We introduce the Continuous Flow Operator (CFO), a framework that learns continuous-time PDE dynamics without the computational burden of standard continuous approaches, e.g., neural ODE. The key insight is repurposing flow matching to directly learn the right-hand side of PDEs without backpropagating through ODE solvers. CFO fits temporal splines to trajectory data, using finite-difference estimates of time derivatives at knots to construct probability paths whose velocities closely approximate the true PDE dynamics. A neural operator is then trained via flow matching to predict these analytic velocity fields. This approach is inherently time-resolution invariant: training accepts trajectories sampled on arbitrary, non-uniform time grids while inference queries solutions at any temporal resolution through ODE integration. Across four benchmarks (Lorenz, 1D Burgers, 2D diffusion-reaction, 2D shallow water), CFO demonstrates superior long-horizon stability and remarkable data efficiency. CFO trained on only 25% of irregularly subsampled time points outperforms autoregressive baselines trained on complete data, with relative error reductions up to 87%. Despite requiring numerical integration at inference, CFO achieves competitive efficiency, outperforming autoregressive baselines using only 50% of their function evaluations, while uniquely enabling reverse-time inference and arbitrary temporal querying.

神经算子连续时间流匹配PDE求解

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