The multilevel fast multipole method
The frequency domain solver is based on Method of Moments in combination with the Multilevel Fast Multipole Method (MLFMM) to improve efficiency. For solving electrically very large problems it can be combined with physical optics in a hybrid approach similar to the one used in the time domain.MLFMM is drastically reducing the solution time. The basic idea is to diagonalize the problem in order to improve solution speed. The diagonalization also significantly reduces the need for memory.
