Inversion of sparse MoM matrices without fill in

This paper describes some new methods for the efficient factorization of sparse representations of moment method matrices. Previous work has described how a general moment method matrix may be transformed into a sparse matrix. The large off diagonal elements in that matrix described physical interactions between modes (e.g. between basis and testing functions) that interact strongly over a long distance. Other modes were created that interact very weakly over long distances, resulting in many small matrix elements and in a sparse matrix. The use of these new modes transformed a full moment method matrix Z into a sparse matrix T.