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arXiv 1206.4136math.NAcs.NA
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变系数亥姆霍兹问题的复合谱方法

A composite spectral scheme for variable coefficient Helmholtz problems

Department of Applied Mathematics, University of Colorado at Boulder(应用数学系,科罗拉多大学博尔德分校)

P. G. Martinsson

AI总结:

提出一种基于高阶谱近似的直接求解方案,用于二维变系数亥姆霍兹问题,预计算复杂度O(N^1.5),求解复杂度O(N log N),数值实验显示高精度和高效性。

摘要:

提出了一种用于二维区域上变系数亥姆霍兹问题的离散化方案。该方案基于高阶谱近似,专为光滑解问题设计。生成的线性方程组使用直接求解器求解,预计算复杂度为O(N^1.5),求解复杂度为O(N log N)。求解器是直接的这一事实是该方案的主要特征,因为迭代方法往往难以处理亥姆霍兹方程。数值例子表明该方案快速且高度精确。例如,使用每波长12个点的离散化,在大小为100×100波长的区域上的亥姆霍兹问题被求解到十位正确数字。计算在办公台式机上执行;涉及160万自由度,预计算需要100秒,实际求解需要0.3秒。

英文摘要:

A discretization scheme for variable coefficient Helmholtz problems on two-dimensional domains is presented. The scheme is based on high-order spectral approximations and is designed for problems with smooth solutions. The resulting system of linear equations is solved using a direct solver with O(N^1.5) complexity for the pre-computation and O(N log N) complexity for the solve. The fact that the solver is direct is a principal feature of the scheme, since iterative methods tend to struggle with the Helmholtz equation. Numerical examples demonstrate that the scheme is fast and highly accurate. For instance, using a discretization with 12 points per wave-length, a Helmholtz problem on a domain of size 100 x 100 wavelengths was solved to ten correct digits. The computation was executed on an office desktop; it involved 1.6M degrees of freedom and required 100 seconds for the pre-computation, and 0.3 seconds for the actual solve.

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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