MLFMA for solving boundary integral equations of 2D electromagnetic scattering at low frequencies

A normalized 2D MLFMA (multilevel fast multipole algorithm) with a computational complexity of O(N) for low frequencies is developed. This normalized 2D MLFMA can be used independently not only at low frequencies, but be merged easily with the dynamic algorithm to solve large-scale problems with dense subgridded areas. Some numerical computations are performed, and good agreement is observed with the plain conjugate gradient method. The null space problem for boundary integral equations at low frequencies is also studied.