Computing the preconditioner for the Schur complement

Abstract

The Newton scheme is used to construct an approximate inverse preconditioner for the Schur complement. However, this scheme is very expensive because of the computation cost of the matrix-matrix product. In this paper, the computation cost of the Newton scheme is reduced by implementing the preconditioner implicitly using the matrix-vector product. We also show that such an implementation is less expensive than computing the preconditioner explicitly.