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arXiv 2302.08035math.NAcs.NAphysics.comp-ph
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基于残差/梯度自适应采样方法的物理信息神经网络求解偏微分方程

Physics-informed neural networks with residual/gradient-based adaptive sampling methods for solving PDEs with sharp solutions

Zhiping Mao, Xuhui Meng

摘要:

在这项工作中,我们考虑使用物理信息神经网络(PINNs)求解具有尖锐解的正向和逆偏微分方程。特别是,为了更好地捕捉解决方案的清晰度,我们提出了自适应采样方法(ASM)的残差和梯度的解决方案的基础上。我们首先提出了一种基于残差的ASM算法,记为ASM I。该方法首先利用少量的残差点对神经网络进行训练,并将计算域划分为若干个子域,然后在残差平均绝对值最大的子域中加入新的残差点,并将该子域中残差绝对值最大的点作为新的残差点加入。我们进一步开发了第二种类型的ASM算法(表示为ASM II)的基础上的残差和梯度的解决方案,由于事实上,只有残差可能无法有效地捕捉的清晰度的解决方案。ASM Ⅱ的步骤与ASM Ⅰ基本相同,只是在ASM Ⅱ中增加了新的残差点,这些残差点不仅具有大的残差,而且具有大的梯度。为了验证本文方法的有效性,我们采用ASM I和ASM II求解了一系列的偏微分方程,包括Burger方程、可压缩Euler方程、L型区域上的泊松方程以及高维泊松方程.数值结果表明,无论采用ASM I还是ASM II算法,都能很好地逼近问题的尖锐解,并且在剩余点数相同的情况下,这两种方法都能比原PINN算法提供更精确的解。此外,ASM II算法具有更好的性能,在准确性,效率和稳定性方面相比,ASM I算法。

英文摘要:

We consider solving the forward and inverse PDEs which have sharp solutions using physics-informed neural networks (PINNs) in this work. In particular, to better capture the sharpness of the solution, we propose adaptive sampling methods (ASMs) based on the residual and the gradient of the solution. We first present a residual only based ASM algorithm denoted by ASM I. In this approach, we first train the neural network by using a small number of residual points and divide the computational domain into a certain number of sub-domains, we then add new residual points in the sub-domain which has the largest mean absolute value of the residual, and those points which have largest absolute values of the residual in this sub-domain will be added as new residual points. We further develop a second type of ASM algorithm (denoted by ASM II) based on both the residual and the gradient of the solution due to the fact that only the residual may be not able to efficiently capture the sharpness of the solution. The procedure of ASM II is almost the same as that of ASM I except that in ASM II, we add new residual points which not only have large residual but also large gradient. To demonstrate the effectiveness of the present methods, we employ both ASM I and ASM II to solve a number of PDEs, including Burger equation, compressible Euler equation, Poisson equation over an L-shape domain as well as high-dimensional Poisson equation. It has been shown from the numerical results that the sharp solutions can be well approximated by using either ASM I or ASM II algorithm, and both methods deliver much more accurate solution than original PINNs with the same number of residual points. Moreover, the ASM II algorithm has better performance in terms of accuracy, efficiency and stability compared with the ASM I algorithm.

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