A modified block preconditioner for complex nonsymmetric indefinite linear systems

摘要

We propose a modified block splitting preconditioner for a class of complex nonsymmetric indefinite linear systems. By adopting two iteration parameters and a relaxing technique, the new preconditioner is much closer to the original coefficient matrix. Theoretical analysis proves that the preconditioned matrix has an eigenvalue 1 with algebraic multiplicity at least n. A theorem concerning the dimension of the Krylov subspace for the preconditioned matrix is also obtained. Finally, some numerical experiments are presented to illustrate the effectiveness of the preconditioner presented.