An improved Greengard-Rokhlin´s fast multipole algorithm for the computation of scattering from many conducting cylinders

We propose an improved Greengard-Rokhlin fast multipole algorithm (GRFMA) whose theoretical complexity is the same as that of MLFMA. We have also considered EM wave scattering from N conducting circular cylinders. In solving the linear system, GRFMA and MLFMA are applied to the computation of matrix-vector product. From numerical examples, the same efficiency and accuracy are confirmed between GRFMA and MLFMA. Because of the low frequency problem, however, the net computation time becomes shorter for GRFMA than for MLFMA.