 FPEAK(2) &gt; 0, and OMEGA is
          infinite, if FPEAK(2) = 0. (If nonzero, FPEAK(2) = 1.)
          For discrete-time systems, it is assumed that the sampling
          period is Ts = 1. If Ts &lt;&gt; 1, the frequency corresponding
          to the peak gain is OMEGA/Ts.

  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
          On entry, the leading N-by-N part of this array must
          contain the state dynamics matrix A.
          On exit, if EQUIL = 'S' and CKPROP = 'N', the