Experience with a Matrix Norm Estimator

Fortran 77 codes for estimating the 1-norm of a real or complex matrix were presented by Higham in [ACM Trans. Math. Software, 14 (1988), pp. 381–396]. The codes have found use in various applications and have been adopted by two program libraries. Further observations about the norm estimation algorithm and experience in using it are reported here. In particular, an example is given where the algorithm requires nearly the maximum possible number of iterations.