In this paper, we propose a two -level block preconditioned Jacobi -Davidson (BPJD) method for efficiently solving discrete eigenvalue problems resulting from finite element approximations of 2 m th ( m = 1 , 2) order symmetric elliptic eigenvalue problems. Our method works effectively to compute the first several eigenpairs, including both multiple and clustered eigenvalues with corresponding eigenfunctions, particularly. The method is highly parallelizable by constructing a new and efficient preconditioner using an overlapping domain decomposition (DD). It only requires computing a couple of small scale parallel subproblems and a quite small scale eigenvalue problem per iteration. Our theoretical analysis reveals that the convergence rate of the method is bounded by c ( H )(1 - C \delta 2 m - 1 H 2 m - 1 ) 2 , where H is the diameter of subdomains and \delta is the overlapping size among subdomains. The constant C is independent of the mesh size h and the internal gaps among the target eigenvalues, demonstrating that our method is optimal and cluster robust. Meanwhile, the H -dependent constant c ( H ) decreases monotonically to 1, as H \rightarrow 0, which means that more subdomains lead to the better convergence rate. Numerical results supporting our theory are given.

Publication:

SIAM Journal on Numerical Analysis Volume 62, Issue 2 Apr 2024

http://dx.doi.org/10.1137/23M1580711

Author:

QIGANG LIANG

School of Mathematical Science, Tongji University, Shanghai 200092, China, and Key Labora-tory of Intelligent Computing and Applications (Tongji University), Ministry of Education

Email: qigangliang@tongji.edu.cn

WEI WANG

LSEC, Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China

Email: ww@lsec.cc.ac.cn

XUEJUN XU

School of Mathematical Science, Tongji University, Shanghai 200092, China, and Key Labora-tory of Intelligent Computing and Applications (Tongji University), Ministry of Education

Email: xxj@lsec.cc.ac.cn