Application of the inner–outer flexible GMRES-FFT method to the analysis of scattering and radiation by cavity-backed patch antennas and arrays

Ssor Preconditioned Inner-Outer Flexible Gmres Method for MLFMM Analysis of Scattering of Open Objects

“…It is desirable to be able to switch within the outer iteration instead of restarting. For the generalized minimum residual method (GMRES) algorithm, this can be easily accomplished with the help of a rather simple modification of the standard algorithm, referred to as the flexible GMRES (FGMRES) [18][19][20][21]. An important property of FGMRES is that it satisfies the residual norm minimization property over the preconditioned Krylov subspace just as in the standard GMRES algorithm.…”

Fast Analysis and Design of Frequency Selective Surface Using the Gmresr-FFT Method

“…The GMRESR-FFT method is used to accelerate the solution of the impedance matrix equation [11][12][13]. This method involves an outer generalized conjugate residual method (GCR) [14] and an inner generalized minimal residual method (GMRES) [15,16], where the inner GMRES acts as a variable preconditioner [13,[17][18][19][20] for the outer GCR. A typical FSS structure is analyzed and the good results demonstrate the validity and efficiency of the proposed algorithm.…”