to the ALPHA-stable part of the original system.
          The Hankel singular values are ordered decreasingly.

</PRE>
<B>Tolerances</B>
<PRE>
  TOL1    DOUBLE PRECISION
          If ORDSEL = 'A', TOL1 contains the tolerance for
          determining the order of reduced system.
          For model reduction, the recommended value of TOL1 lies
          in the interval [0.00001,0.001].
          If TOL1 &lt;= 0 on entry, the used default value is
          TOL1 = NS*EPS, where NS is the number of
         