A Directional Interpolation Pattern for Multilevel Green's Function Interpolation Method

Multilevel Green's function interpolation method (MLGFIM) is a fast numerical method whose computational complexity is O(N log N). Since MLGFIM is based on interpolation techniques, the efficiency of MLGFIM is highly associated with the number of interpolation points. To improve the efficiency of MLGFIM, a directional interpolation pattern for decreasing the required number of interpolation points is proposed. With the directional interpolation pattern, the number of interpolation points in the tangent directions can be decreased because the phase in the tangent direction oscillates mush mildly than that in the radial direction. As a result, the total required number of interpolation points decreases and the efficiency of MLGFIM improves.