The recursive aggregated interaction matrix algorithm

W.C. Chew and C.C. Lu

The recursive aggregate interaction mtrix algorithm (RAIMA) for calculating a wave scattering solution is developed. This algorithm combines the strength of both the recursive aggregate T matrix algorithm (RATMA) and the recursive interaction matrix algorithm (RIMA) that have been previously developed. The resultant algorithm is robust for scattering problems involving highly singular Green's functions by avoiding the violation of the addition theorem. It also has reduced computational complexity for inverting the volume integral equation of scattering. The computational complexity of RAIMA is O(N^(7/3)) in three dimensions and O(N^2) in two dimensions.