rollable
          and unobservable poles before computing the norm, as
          follows:
          = 'R': reduce the system order;
          = 'N': compute the norm without reducing the order.
          If CKPROP = 'N', this option is ineffective.

  POLES   CHARACTER*1
          Specifies whether the user wishes to use all or part of
          the poles to compute the test frequencies (in the non-
          iterative part of the algorithm), or all or part of the
          midpoints (in the iterative part