论文标题
用于计算参数依赖性矩阵特征值的Tensor-Krylov方法
Tensor-Krylov method for computing eigenvalues of parameter-dependent matrices
论文作者
论文摘要
在本文中,我们将残留的Arnoldi方法扩展到计算极端特征值(例如,最大的实际部分,主要的,...)到矩阵依赖参数的情况。这种Arnoldi方法与经典Arnoldi算法之间的差异在于,在前者中,残差被添加到子空间中。我们开发了一种张量 - 克里洛夫方法,该方法同时应用了剩余的arnoldi方法(RA)。子空间包含所有这些点的近似Krylov空间。而是将所有参数值的残差添加到子空间中,而是创建由这些残差组成的矩阵的低级别近似值,并仅将列空间添加到子空间。为了保持计算有效,需要限制子空间的维度,并在子空间达到规定的最大维度后重新启动。这种方法的新颖性是双重的。首先,我们观察到允许低级别近似值的较大误差而不会减慢收敛性,这意味着我们可以在重新启动之前进行更多迭代。其次,我们特别关注子空间重新启动的方式,因为在我们的情况下,经典重新启动技术使得太大的子空间。我们激励着为什么只能保持搜索特征向量的近似值足够好。在论文的末尾,我们将此算法扩展到换档剩余的Arnoldi方法,以计算特征值接近移位$σ$的特定值,以供特定的参数依赖关系。我们提供理论结果并报告数值实验。 MATLAB代码公开可用。
In this paper we extend the Residual Arnoldi method for calculating an extreme eigenvalue (e.g. largest real part, dominant,...) to the case where the matrices depend on parameters. The difference between this Arnoldi method and the classical Arnoldi algorithm is that in the former the residual is added to the subspace. We develop a Tensor-Krylov method that applies the Residual Arnoldi method (RA) for a grid of parameter points at the same time. The subspace contains an approximate Krylov space for all these points. Instead of adding the residuals for all parameter values to the subspace we create a low-rank approximation of the matrix consisting of these residuals and add only the column space to the subspace. In order to keep the computations efficient, it is needed to limit the dimension of the subspace and to restart once the subspace has reached the prescribed maximal dimension. The novelty of this approach is twofold. Firstly, we observed that a large error in the low-rank approximations is allowed without slowing down the convergence, which implies that we can do more iterations before restarting. Secondly, we pay particular attention to the way the subspace is restarted, since classical restarting techniques give a too large subspace in our case. We motivate why it is good enough to just keep the approximation of the searched eigenvector. At the end of the paper we extend this algorithm to shift-and-invert Residual Arnoldi method to calculate the eigenvalue close to a shift $σ$ for a specific parameter dependency. We provide theoretical results and report numerical experiments. The Matlab code is publicly available.