ix of the original Riccati
          equation (with matrix A), if LYAPUN = 'O', or of the
          "reduced" Riccati equation (with matrix T), if
          LYAPUN = 'R'. See METHOD.

  LDX     INTEGER
          The leading dimension of the array X.  LDX &gt;= max(1,N).

  SEPD    (output) DOUBLE PRECISION
          If JOB = 'C' or JOB = 'B', the estimated quantity
          sepd(op(Ac),op(Ac)').
          If N = 0, or X = 0, or JOB = 'E', SEPD is not referenced.

  RCOND   (output) DOUBLE PRECISION
       