“…There exist a lot of fast integral equation methods that can be used to enhance the efficiency of the solution, for instance, FMM [12,[19][20][21], CGFFT [22,23], Pre-corrected FFT [24], SMCG [25], AIM [26], IceCube [27], IMLMQRF [11,28], and MLGFIM [1,2] and so on. In them, 1) FMM is the fastest method with O(N ) complexity for quasistatic problems; 2) SMCG, CGFFT, Pre-corrected FFT, SMCG, and AIM are FFT based methods with O(N log N ) complexity; 3) Ice Cube and IMLMQRF are the methods based on matrix compression technique, i.e., QR factorization, matrix merging, and matrix column and row sampling techniques; 4) MLGFIM is based on a hierarchical structure that is similar to FMM but using the Green's function matrix interpolation method with QR factorization technique.…”