An embedded iterative scheme in electromagnetism

In this paper we describe an embedded iterative scheme based on the GMRES method for the solution of large electromagnetic scattering problems expressed in an integral formulation. In our scheme, we use a Frobenius-norm minimization preconditioner to speed-up the inner iterations, and the M-V products are carried out using the Fast Multipole Method at different accuracy within the inner and the outer solvers. We show that the proposed technique enables to significantly reduce the computational cost of the simulation on large industrial and academic models. In particular, we are able to solve a linear system with more than one million unknowns arising from a simulation on a real aircraft.