论文标题

求解部分微分方程的神经网络:与有限元素的比较

Neural Networks to solve Partial Differential Equations: a Comparison with Finite Elements

论文作者

Sacchetti, Andrea, Bachmann, Benjamin, Löffel, Kaspar, Künzi, Urs-Martin, Paoli, Beatrice

论文摘要

我们比较了带有神经网络(NN)模拟的孔的标准部分微分方程热问题的有限元方法(FEM)模拟。从FEM获得的最大偏差(在Unity上使用的解决方案$ 0.015 $)也很容易通过NN轻松实现,而无需对超参数进行太多调整。相反,$ 0.01 $的准确性需要使用替代优化器进行改进,以便与NN达到类似的性能。作为计算性能的机器独立量化,浮点操作值之间的粗略比较表明,FEM和NN之间有明显的差异,反对前者。这也很强地适用于计算时间:对于$ 10^{-5} $的准确性,fem和nn分别需要$ 54 $和$ 1100 $秒。对改变不同的超参数的影响的详细分析表明,准确性和计算时间仅弱取决于其中的主要部分。 “ Adam''优化器无法实现低于$ 0.01 $的准确性,似乎完全无法实现$ 10^{ - 5} $的准确性。总而言之,目前的工作表明,对于求解稳态2D热量方程式的具体案例,与网络相比,稳态2D热量方程相比,fem algorithm的性能要好。

We compare the Finite Element Method (FEM) simulation of a standard Partial Differential Equation thermal problem of a plate with a hole with a Neural Network (NN) simulation. The largest deviation from the true solution obtained from FEM ($0.015$ for a solution on the order of unity) is easily achieved with NN too without much tuning of the hyperparameters. Accuracies below $0.01$ instead require refinement with an alternative optimizer to reach a similar performance with NN. A rough comparison between the Floating Point Operations values, as a machine-independent quantification of the computational performance, suggests a significant difference between FEM and NN in favour of the former. This also strongly holds for computation time: for an accuracy on the order of $10^{-5}$, FEM and NN require $54$ and $1100$ seconds, respectively. A detailed analysis of the effect of varying different hyperparameters shows that accuracy and computational time only weakly depend on the major part of them. Accuracies below $0.01$ cannot be achieved with the "adam'' optimizers and it looks as though accuracies below $10^{-5}$ cannot be achieved at all. In conclusion, the present work shows that for the concrete case of solving a steady-state 2D heat equation, the performance of a FEM algorithm is significantly better than the solution via networks.

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