Emeric Martin : July 1, 2003

Using spectral information for accelerating the convergence of Gmres for large electromagnetic calculations.

Abstract

For solving dense complex systems, such as those involved in certain formulations in electromagnetism, we test the efficiency of a new preconditioning technique. The idea is to shift the smallest eigenvalues of the initial preconditioned system close to one in order to obtain faster convergence of the Krylov solvers. For that purpose, we consider an eigendecomposition using ARPACK to make a spectral low-rank update of the initial preconditioner. Numerical experiments on parallel distributed memory computers will be presented on large real-life industrial problems.