Estimation of the Distance to a Nearest Rectangular Polynomial Matrix with a Prescribed Eigenvalue

Given a rectangular matrix polynomial, these MATLAB routines are intended to estimate the distance to and locate a nearest rectangular polynomial with an eigenvalue under general complex perturbations, as well as real perturbations. These nonconvex optimization problems are solved globally by exploiting their singular value optimization characterizations via level-set methods and algorithms, built based on Lipschitz continuity of singular value functions.