
                if DISCR = .FALSE., this means that while the matrix
                A has computed eigenvalues with negative real parts,
                it is only just stable in the sense that small
                perturbations in A can make one or more of the
                eigenvalues have a non-negative real part;
                if DISCR = .TRUE., this means that while the matrix
                A has computed eigenvalues inside the unit circle,
                it is nevertheless only just converge