E. Michielssen et A. Boag, A MULTILEVEL MATRIX DECOMPOSITION ALGORITHM FOR ANALYZING SCATTERING FROM LARGE STRUCTURES, IEEE transactions on antennas and propagation, 44(8), 1996, pp. 1086-1093
A multilevel algorithm is presented for analyzing scattering from elec
trically large surfaces, The algorithm accelerates the iterative solut
ion of integral equations that arise in computational electromagnetics
, The algorithm permits a fast matrix-vector multiply by decomposing t
he traditional method of moment matrix into a large number of blocks,
with each describing the interaction between distant scatterers, The m
ultiplication of each block by a trial solution vector is executed usi
ng a multilevel scheme that resembles a fast Fourier transform (FFT) a
nd that only relies on well-known algebraic techniques. The computatio
nal complexity and the memory requirements of the proposed algorithm a
re O(N log(2)N).