Abstract: In order to efficiently solve large-scale asymmetric dense linear matrix in discrete field integral
equations, a preconditioned restarted changing minimal residual method based on the Hessenberg process
(CMRH) is proposed. It is used to implement the modified multilevel fast multi-pole algorithm (MLFMA)
to compute the scattering problem of perfect electric conductors in a lossy half space. MLFMA is used
to accelerate matrix vector multiplication of the CMRH. Scattering characteristics of the cylinder, the box
and the missile model are presented. Numerical results show that the CMRH method can efficiently reduce
both iteration number and convergence time as compared to the generalized minimal residual (GMRES).
Furthermore, CMRH is more easily combined with sparse approximate inverse (SAI) and symmetric successive
over relaxation (SSOR) preconditioning techniques, making it more practical.