A Simple Set of Test Matrices for Eigenvalue Programs
C. William Gear · Mathematics of Computation · 1969
Sets of simple matrices of order $N$ are given, together with all of their eigenvalues and right eigenvectors, and simple rules for generating their inverses in the nonsingular cases. In general, these matrices are nonsymmetric. They can have sets of double and triple roots. In each of these cases, two of the roots of the doublet or triplet can correspond to a single eigenvector.