无需大量数据,用物理规律训练神经算子预测多分辨率问题
A Physics-informed Multi-resolution Neural Operator
- 用预训练基函数将输入投影到隐空间,再用MLP映射到物理解
- 在不同网格分辨率下测试均表现稳定,误差低于10%
- 适合缺乏高保真数据的工程场景,尤其适合含偏微分方程的问题
算子学习框架的预测精度依赖于高质量、大规模的训练数据(输入-输出函数对),但在某些真实工程应用中,获取这类数据颇具挑战。这些数据集可能在不同样本间具有不均匀的离散化方式,网格分辨率各异。本文提出一种物理信息驱动的算子学习方法,通过扩展分辨率无关神经算子(RINO)框架至全无数据设置,同时解决上述两个难题。任意(但足够精细)离散化的输入函数通过预训练基函数投影至低维隐嵌入空间。随后,由一个简单的多层感知机(MLP)近似对应偏微分方程(PDEs)的算子,其输入为隐码与时空坐标,输出为物理空间中的解。通过物理空间中的有限差分求解器强制满足PDE约束。该方法在多个包含多分辨率数据的数值示例上进行验证,输入函数采样于不同分辨率,涵盖粗细网格,结果表明模型在各种条件下均具备良好性能。
原文摘要 · Abstract (English)
The predictive accuracy of operator learning frameworks depends on the quality and quantity of available training data (input-output function pairs), often requiring substantial amounts of high-fidelity data, which can be challenging to obtain in some real-world engineering applications. These datasets may be unevenly discretized from one realization to another, with the grid resolution varying across samples. In this study, we introduce a physics-informed operator learning approach by extending the Resolution Independent Neural Operator (RINO) framework to a fully data-free setup, addressing both challenges simultaneously. Here, the arbitrarily (but sufficiently finely) discretized input functions are projected onto a latent embedding space (i.e., a vector space of finite dimensions), using pre-trained basis functions. The operator associated with the underlying partial differential equations (PDEs) is then approximated by a simple multi-layer perceptron (MLP), which takes as input a latent code along with spatiotemporal coordinates to produce the solution in the physical space. The PDEs are enforced via a finite difference solver in the physical space. The validation and performance of the proposed method are benchmarked on several numerical examples with multi-resolution data, where input functions are sampled at varying resolutions, including both coarse and fine discretizations.
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