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arXiv 1709.10337math.NAcs.NAphysics.comp-ph
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用于迭代隐式方法的自适应步长控制器

An adaptive step size controller for iterative implicit methods

University of Innsbruck(因斯布鲁克大学)

Lukas Einkemmer

AI总结:

本文提出了一种自适应步长选择策略,通过减少单位时间步的计算成本提升性能,适用于多种问题。传统方法强调时间步长的平滑性,而本文强调探索不同步长以实现快速变化。

摘要:

自动选择合适的时间步长在文献中已被广泛研究。然而,大多数策略均假设每个时间步的计算成本与步长无关。这种假设适用于非刚性常微分方程和通过直接方法求解的偏微分方程。然而,若使用迭代(如Krylov)方法,则通常不成立。本文提出了一种步长选择策略,该策略在模拟过程中自适应地减少单位时间步的计算成本,受指定容差约束。我们证明该方法在扩散-对流方程、带反应项的Burgers方程、孔隙介质方程、粘性Burgers方程、Allen-Cahn方程以及二维Brusselator系统等广泛问题中表现出显著性能提升。尽管传统步长控制器强调时间步长的平滑序列,我们强调探索不同步长,这需要相对快速的步长变化。

英文摘要:

The automatic selection of an appropriate time step size has been considered extensively in the literature. However, most of the strategies developed operate under the assumption that the computational cost (per time step) is independent of the step size. This assumption is reasonable for non-stiff ordinary differential equations and for partial differential equations where the linear systems of equations resulting from an implicit integrator are solved by direct methods. It is, however, usually not satisfied if iterative (for example, Krylov) methods are used. In this paper, we propose a step size selection strategy that adaptively reduces the computational cost (per unit time step) as the simulation progresses, constraint by the tolerance specified. We show that the proposed approach yields significant improvements in performance for a range of problems (diffusion-advection equation, Burgers' equation with a reaction term, porous media equation, viscous Burgers' equation, Allen--Cahn equation, and the two-dimensional Brusselator system). While traditional step size controllers have emphasized a smooth sequence of time step sizes, we emphasize the exploration of different step sizes which necessitates relatively rapid changes in the step size.

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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