In this paper we initiate a program to study the controllability properties
of matrix eigenvalue algorithms arising in numerical linear algebra. Our f
ocus is on a well-known eigenvalue method, the inverse power iteration defi
ned on projective space. A complete characterization of the reachable sets
and their closures is given via cyclic invariant subspaces. Moreover, a nec
essary and sufficient condition for almost controllability of the inverse p
ower method is derived. (C) 2000 Elsevier Science B.V. All rights reserved.