ON COMPUTATION OF THE STABILITY RADIUS FOR NONLINEARLY STRUCTURED PERTURBATIONS

This paper considers the problem of finding a perturbation matrix with the least spectral norm such that a matrix-valued function becomes si ngular, where the dependence of the function on the perturbation is al lowed to be nonlinear. It is proved that such a problem can be approxi mated by a smooth unconstrained minimization problem with compact subl evel sets. A computational procedure proposed based on this result is demonstrated to be effective in both linear and nonlinear cases. (C) 1 998 Published by Elsevier Science B.V. All rights reserved.