Applying matrix rotation to the three-dimensional low-frequency multilevelfast multipole algorithm

The matrix rotation technique is applied to three-dimensional (3-D) multile vel fast multipole algorithm (MLFMA) at very low frequencies (LF) to save t he storage without increasing the order of the floating-point operations. S ome symmetrical properties of the translation matrices along the z-directio n for the 3-D LF-MLFMA and the static MLFMA are also derived to further red uce the memory requirement Numerical results shown that the order of errors introduced by the matrix rotation is much smaller than the order of errors from the plain LF-MLFMA or plain static MLFMA. The implementation of the m atrix technique does not change the precision order of the LF-MLFMA and the static MLFMA for fixed truncation of multipole expansions. (C) 2000 John W iley & Sons, Inc.