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arXiv 2101.06182math.NAcs.LGcs.NA
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STENCIL-NET:数据驱动的解自适应离散化偏微分方程

STENCIL-NET: Data-driven solution-adaptive discretization of partial differential equations

Max Planck Institute of Molecular Cell Biology and Genetics(马克斯·普朗克分子细胞生物学与遗传学研究所);ONI;Flatiron Institute(熨斗研究所)

Suryanarayana Maddu, Dominik Sturm, Bevan L. Cheeseman, Christian L. Müller, Ivo F. Sbalzarini

摘要:

近似求解偏微分方程(PDE)的数值方法是科学计算的核心。通常,这需要高分辨率或自适应离散化网格来捕获PDE解决方案中的相关时空特征,例如,在湍流、燃烧和冲击传播等应用中。数值逼近也需要知道偏微分方程,以便构造特定问题的离散化。然而,系统地推导出这样的解自适应离散算子是当前的挑战。在这里,我们提出了STENCIL-NET,一个人工神经网络架构的数据驱动学习的问题和分辨率特定的非线性偏微分方程的局部离散化。STENCIL-NET通过在常规笛卡尔网格上进行空间和时间自适应参数池化,并结合有关离散时间积分的知识,实现了未知非线性PDE中算子的数值稳定离散化。不需要知道实际的PDE,因为解数据足以训练网络来学习离散算子。一次训练的STENCIL-NET模型可用于在更大的空间域上预测PDE的解,并且比训练时间更长,从而解决了PDE约束的数据外推问题。为了支持这一主张,我们提出了长期预测的混沌PDE解决方案的粗时空网格的数值实验。我们还量化了通过用无方程STENCIL-NET预测替代基线数值方法在较粗网格上实现的速度提高,并且几乎不影响精度。

英文摘要:

Numerical methods for approximately solving partial differential equations (PDE) are at the core of scientific computing. Often, this requires high-resolution or adaptive discretization grids to capture relevant spatio-temporal features in the PDE solution, e.g., in applications like turbulence, combustion, and shock propagation. Numerical approximation also requires knowing the PDE in order to construct problem-specific discretizations. Systematically deriving such solution-adaptive discrete operators, however, is a current challenge. Here we present STENCIL-NET, an artificial neural network architecture for data-driven learning of problem- and resolution-specific local discretizations of nonlinear PDEs. STENCIL-NET achieves numerically stable discretization of the operators in an unknown nonlinear PDE by spatially and temporally adaptive parametric pooling on regular Cartesian grids, and by incorporating knowledge about discrete time integration. Knowing the actual PDE is not necessary, as solution data is sufficient to train the network to learn the discrete operators. A once-trained STENCIL-NET model can be used to predict solutions of the PDE on larger spatial domains and for longer times than it was trained for, hence addressing the problem of PDE-constrained extrapolation from data. To support this claim, we present numerical experiments on long-term forecasting of chaotic PDE solutions on coarse spatio-temporal grids. We also quantify the speed-up achieved by substituting base-line numerical methods with equation-free STENCIL-NET predictions on coarser grids with little compromise on accuracy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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