MC75: Sparse unsymmetric matrix: estimate condition number

This subroutine provides estimates of the classical condition number, \({|| \mathbf{ A} ||} _{\infty} { || \mathbf{ A} ^{-1} || }_{\infty}\), and Skeel’s condition number, \(||\; | \mathbf{ A} ^{-1} |\; | \mathbf{ A} | \; || _{\infty}\), of an \(n \times n\) sparse matrix \(\mathbf{ A}\). We denote by \(| \mathbf{ A} |\) and \(| \mathbf{ A} ^{-1} |\) the matrices whose entries are the absolute values of the entries in \(\mathbf{ A}\) and \(\mathbf{ A} ^{-1}\).