Symbolic computation of -inverses using QDR factorization

Efficient evaluation of the full-rank QDR decomposition is established. A method and algorithm for efficient symbolic computation of inverses of a given rational matrix A is defined using the full-rank QDR decomposition of an appropriate rational matrix W. The algorithm is implemented using MATHEMATICA’s ability to deal with symbolic expressions as well as with numbers. Examples including polynomial and rational matrices are presented. Some comparisons with well-known methods for symbolic evaluation of generalized inverses are obtained.