A family of test matrices
A. C. R. Newbery · Communications of the ACM · 1964
A family of test matrices with the following properties is described here: (a) an explicit inverse is given; (b) the characteristic polynomial is easily obtained; (c) a large measure of control over the eigenvalues is possible; (d) in special cases the eigenvalues and eigenvectors can be given explicitly, and the P -condition number can be arbitrarily assigned.