Preconditioned iterative solution of scattering from rough surfaces

Extensions to the functionally identical forward-backward (FB) and method o f ordered multiple interactions iterative techniques have recently been int roduced that improve the convergence characteristics with specific scatteri ng geometries. These extensions are shown to be mathematically equivalent t o applying preconditioners to the discretized integral equation that is ite ratively solved. The same preconditioners can be used with any iterative so lution technique. Numerical examples show that the generalized minimal resi dual (GMRES) and bi-conjugate gradient-stable (BICGSTAB) algorithms give si milarly rapid convergence when applied to a preconditioned discretized inte gral equation.