The application of the iterative near-zone preconditioning method to accelerate multilevel fast multipole method

In this paper, the iterative near-zone preconditioning method with MLFMM technique is introduced for the iterative solution of CFIE formulations. The preconditioner is derived from the strongest matrix elements of the coupling matrix and its iteration avoids the typical fill-in problem associated with direct factorization methods. It is found that the iterative near-zone preconditioning method can considerably speed up the convergence for the CFIE system. In the future, the more suitable preconditioning technique is proposed to accelerate their convergence