A Sophisticated Parallel MLFMA for Scattering by Extremely Large Targets

The development of the MLFMA for realistic targets is currently at the stage where clever implementation, using a series of tricks based on the characteristics of the MLFMA and current computer technology, is required. A sophisticated parallel MLFMA for use on distributed-memory computers is presented as a whole picture of developing the program using a style of multilevel development in this paper. A series of implementation tricks for the parallel MLFMA are analyzed and compared. Particularly, a novel trick for reducing the truncation numbers is presented for extremely large targets, in the paper. These tricks are integrated into a sophisticated parallel MLFMA. The memory requirement and the CPU time for each part in each level are analyzed numerically by typical numerical experiments. The capability of this sophisticated parallel MLFMA is demonstrated by computing scattering by a sphere with a diameter of 480 wavelengths, containing around 130 million unknowns, and for a plane model with a fuselage of more than 1000 wavelengths, containing more than 72 million unknowns. These are the largest scattering problems ever solved by full-wave numerical methods, to our knowledge.