arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2303.08950math.NAcs.NAmath.OC
收藏

变分时间隐式格式的高阶空间离散:Wasserstein梯度流与反应-扩散系统

High order spatial discretization for variational time implicit schemes: Wasserstein gradient flows and reaction-diffusion systems

Guosheng Fu, Stanley Osher, Wuchen Li

AI总结:

本文为广义最优传输空间中的梯度流构造一阶时间隐式广义JKO变分格式,结合ALG2与高阶有限元实现稳定迭代求解,并通过多类二维PDE验证有效性。

摘要:

我们针对广义最优传输度量空间中的初值梯度流,设计并计算了具有高阶空间离散的一阶时间隐式变分格式。我们首先从Onsager原理回顾广义最优传输空间中梯度流的若干例子。随后,我们将一步时间松弛优化问题用于时间隐式格式,即广义Jordan-Kinderlehrer-Otto格式。其极小化系统满足初值梯度流的时间隐式格式,并具有一阶时间精度。我们采用一阶优化格式ALG2(增广Lagrange方法)以及空间离散中的高阶有限元方法来计算该一步优化问题。这使我们能够迭代地导出初值梯度流的时间隐式更新。我们指出,ALG2中的迭代具有基于最优传输和Onsager激活函数、易于实现的逐点更新。对于凸情形,所提出的方法是无条件稳定的。文中给出数值例子,以证明这些方法在二维PDE中的有效性,包括Wasserstein梯度流、Fisher–Kolmogorov-Petrovskii-Piskunov方程,以及二组分和四组分可逆反应-扩散系统。

英文摘要:

We design and compute first-order implicit-in-time variational schemes with high-order spatial discretization for initial value gradient flows in generalized optimal transport metric spaces. We first review some examples of gradient flows in generalized optimal transport spaces from the Onsager principle. We then use a one-step time relaxation optimization problem for time-implicit schemes, namely generalized Jordan-Kinderlehrer-Otto schemes. Their minimizing systems satisfy implicit-in-time schemes for initial value gradient flows with first-order time accuracy. We adopt the first-order optimization scheme ALG2 (Augmented Lagrangian method) and high-order finite element methods in spatial discretization to compute the one-step optimization problem. This allows us to derive the implicit-in-time update of initial value gradient flows iteratively. We remark that the iteration in ALG2 has a simple-to-implement point-wise update based on optimal transport and Onsager's activation functions. The proposed method is unconditionally stable for convex cases. Numerical examples are presented to demonstrate the effectiveness of the methods in two-dimensional PDEs, including Wasserstein gradient flows, Fisher--Kolmogorov-Petrovskii-Piskunov equation, and two and four species reversible reaction-diffusion systems.

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。

↑