论文标题
基于张量的技术,用于快速离散化和3D椭圆方程的解决方案,具有随机系数
Tensor-based techniques for fast discretization and solution of 3D elliptic equations with random coefficients
论文作者
论文摘要
在本文中,我们提出和分析了在$ \ mathbb {r}^d $,$ d = 2,3 $中随机介质中快速解决周期性椭圆问题的快速解决方案的数值算法。我们考虑使用基于大型$ l \ times l \ times l $ lattice构建的方程系数的棋盘配置的随机实现,其中$ l $是代表性音量元素的大小。引入了Kronecker张量产品方案,以快速生成刚度矩阵,以在张量网格上离散化。我们描述了在周期性环境中构建低kronecker秩的张量技术,以在PCG迭代的框架中使用。在我们的构造中,在傅立叶基础上表示的离散拉普拉斯反向的对角矩阵被重塑为3D张量,然后由低级别的规范张量近似,该量子由多摩尔德tucker-tucker tucker-tucker-tucker-andonical tensor转换计算出来。详细描述了张量网格上的FDM离散化方案,并说明了PCG迭代的3D MATLAB实现的$ L $的计算特性。目前的工作延续了[22]中的发展,其中对2D椭圆形PDE的均质矩阵的渐近收敛率与$ l $进行了数值研究。在3D随机均质化问题的数值分析中,可以应用所提出的椭圆问题求解器,以计算随机实现的长序列,以解决3D准周期几何几何均质化问题,以及在动态的许多身体相互作用过程和多部分电术的动态模拟中。
In this paper, we propose and analyze the numerical algorithms for fast solution of periodic elliptic problems in random media in $\mathbb{R}^d$, $d=2,3$. We consider the stochastic realizations using checkerboard configuration of the equation coefficients built on a large $L \times L \times L$ lattice, where $L$ is the size of representative volume elements. The Kronecker tensor product scheme is introduced for fast generation of the stiffness matrix for FDM discretization on a tensor grid. We describe tensor techniques for the construction of the low Kronecker rank spectrally equivalent preconditioner in periodic setting to be used in the framework of PCG iteration. In our construction the diagonal matrix of the discrete Laplacian inverse represented in the Fourier basis is reshaped into a 3D tensor, which is then approximated by a low-rank canonical tensor, calculated by the multigrid Tucker-to-canonical tensor transform. The FDM discretization scheme on a tensor grid is described in detail, and the computational characteristics in terms of $L$ for the 3D Matlab implementation of the PCG iteration are illustrated. The present work continues the developments in [22], where the numerical primer to study the asymptotic convergence rate vs. $L$ for the homogenized matrix for 2D elliptic PDEs with random coefficients was investigated numerically. The presented elliptic problem solver can be applied for calculation of long sequences of stochastic realizations in numerical analysis of 3D stochastic homogenization problems, for solving 3D quasi-periodic geometric homogenization problems, as well as in the numerical simulation of dynamical many body interaction processes and multi-particle electrostatics.