A sparse moment method technique for a wide class of scattering problems

In this paper, the problem of making the full matrix sparse is addressed. It was observed that the interaction between elements lying physically far away from each other is small. If they are sufficiently far away, the interaction should be almost negligible, i.e., the matrix entry can be zeroed out as a first approximation. Thus, the full matrix reduces to a sparse matrix, although the number of elements to be zeroed out depends on the size of the body and accuracy of the desired results. For solving large body scattering, this technique should work even better since the percentage of sparsity increases as a function of the physical size of the body. An important component of this technique is the capability to improve upon the approximation in an iterative manner without using additional storage resources. One or two iterations beyond the first yields the correct result provided certain sparsity criteria are satisfied.