Before revision:  These dangerous eigenvalues contribute to large round-off errors in the first iteration, but are self-correcting in later iterations  .
After revision:  These dangerous eigenvalues contribute to large round-off errors in the first iteration, but are self-correcting in later iterations . For matrices with orthogonal eigenvectors (e.g., real-symmetric or complex Hermitian), two iterations is enough to reduce round-off errors to the order of the unit-round off .