Function Reference
— Function File: [n, c] = normest (a, tol)

Estimate the 2-norm of the matrix a using a power series analysis. This is typically used for large matrices, where the cost of calculating the norm (a) is prohibitive and an approximation to the 2-norm is acceptable.

tol is the tolerance to which the 2-norm is calculated. By default tol is 1e-6. c returns the number of iterations needed for normest to converge.