Preconditioners and Their Analyses for Edge Element Saddle-point Systems Arising from Time-harmonic Maxwell Equations
This work addresses the need for efficient solvers for Maxwell equations in computational electromagnetics, but the results are incremental as they extend existing preconditioning techniques.
The paper proposes and analyzes new preconditioners for saddle-point systems from edge element discretization of time-harmonic Maxwell equations. For vanishing wave numbers, the Hiptmair-Xu solver is shown to be efficient; for non-vanishing wave numbers, PCG with a new preconditioner works for small wave numbers, while preconditioned MINRES with existing or new preconditioners works for large wave numbers. Numerical experiments demonstrate efficiency.
We shall propose and analyze some new preconditioners for the saddle-point systems arising from the edge element discretization of the time-harmonic Maxwell equations in three dimensions. We will first consider the saddle-point systems with vanishing wave number, for which we present an important relation between the solutions of the singular curl-curl system and the non-singular saddle-point system, then demonstrate that the saddle-point system can be efficiently solved by the Hiptmair-Xu solver. For the saddle-point systems with non-vanishing wave numbers, we will show that the PCG with a new preconditioner can apply for the non-singular system when wave numbers are small, while the methods like preconditioned MINRES may apply for some existing and new preconditioners when wave numbers are large. The spectral behaviors of the resulting preconditioned systems for the existing and new preconditioners are analyzed and compared, and numerical experiments are presented to demonstrate and compare the efficiencies of these preconditioners.