Flexible BiCGStab to Solve the Discretized EFIE in Scattering Computation

The Bi-Conjugate Gradient Stabilized method is able to handlke and solve large linear systems, such as arising from electromagnetic scattering inverse problems formulated by EFIE and discretized by the Galerkin Method of Moments by means of well-known Rao-Wilton-Glisson method. Neverthless, preconditioning phase should be taken into account very carefully, in order to maintain the advantages of the use of Krylov subspaces in solving sparse inverse linear problems. In this sense, flexible version of the Bi-Conjugate Gradient Method Stabilized algorithm received small attention, but could be really worthwhile for a correct and fast preconditioning. In this work, we propose a numerical study on its performances. Results demonstrate that Flexible Bi-Conjugate Gradient Stabilized is faster and more robust than the standard version coupled with diagonal or ILU preconditioning, at least in specific cases involving electromagnetic inverse scattering.