Structured preconditioners for operator equations

Abstract

SUMMARYWe propose and report on the use of block circulant preconditioners for solution of non-Hermitian linear systems in one important typical application from computational electromagnetics (evaluation of ÿelds from localized sources in a heterogeneous isotropic formation uniform in one particular direction). The essentials of the e ciency and discussion are the fast approximation method (based on Fourier polynomials) and fast algebraic solver (GMRES with block circulant preconditioners).