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arXiv 2103.08662cs.LGastro-ph.COastro-ph.GAgr-qchep-lat
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dNNsolve:一种高效的基于神经网络的PDE求解器

dNNsolve: an efficient NN-based PDE solver

DESY(德国电子同步加速器研究所);University of Cambridge(剑桥大学);DAMTP(应用数学与理论物理系);CTC(理论宇宙学中心)

Veronica Guidetti, Francesco Muia, Yvette Welling, Alexander Westphal

摘要:

神经网络(NN)可以通过将问题重新定义为优化问题来求解常微分方程和偏微分方程(ODE和PDE)。要优化的目标函数是要求解的PDE和初始/边界条件的平方和。训练前馈NN以最小化在从定义问题的域中采样的一组配置点上评估的该损失函数。一个紧凑和光滑的解决方案,只依赖于训练的神经网络的权重,然后获得。这种方法通常被称为PINN,来自Physics Informed神经网络~ \cite{raissi2017physics_1, raissi2017physics_2}。尽管PINN方法在解决各种类型的偏微分方程方面取得了成功,但这种思想的实现能够以良好的精度解决一大类常微分方程和偏微分方程,而无需微调网络的超参数,目前还没有。在本文中,我们介绍了这个概念的一个新的实现-称为dNNsolve -利用双神经网络来解决常微分方程/偏微分方程。其中包括:i)正弦和S形激活函数,其提供更有效的基础来捕获解中的长期和周期性模式; ii)新设计的架构,其使得NN容易使用上述基函数来近似解。我们表明,dNNsolve是能够解决广泛的常微分方程/偏微分方程在1,2和3时空维度,而不需要超参数微调。

英文摘要:

Neural Networks (NNs) can be used to solve Ordinary and Partial Differential Equations (ODEs and PDEs) by redefining the question as an optimization problem. The objective function to be optimized is the sum of the squares of the PDE to be solved and of the initial/boundary conditions. A feed forward NN is trained to minimise this loss function evaluated on a set of collocation points sampled from the domain where the problem is defined. A compact and smooth solution, that only depends on the weights of the trained NN, is then obtained. This approach is often referred to as PINN, from Physics Informed Neural Network~\cite{raissi2017physics_1, raissi2017physics_2}. Despite the success of the PINN approach in solving various classes of PDEs, an implementation of this idea that is capable of solving a large class of ODEs and PDEs with good accuracy and without the need to finely tune the hyperparameters of the network, is not available yet. In this paper, we introduce a new implementation of this concept - called dNNsolve - that makes use of dual Neural Networks to solve ODEs/PDEs. These include: i) sine and sigmoidal activation functions, that provide a more efficient basis to capture both secular and periodic patterns in the solutions; ii) a newly designed architecture, that makes it easy for the the NN to approximate the solution using the basis functions mentioned above. We show that dNNsolve is capable of solving a broad range of ODEs/PDEs in 1, 2 and 3 spacetime dimensions, without the need of hyperparameter fine-tuning.

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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