)matrix whose estimated
          condition number is less than 1/TOL(3) is considered to be
          of full rank.  If the user sets TOL(3) &lt;= 0, then an
          implicitly computed, default tolerance, defined by
          TOLDEF1 = N*N*EPS, is used instead.  TOL(3) &lt; 1.
          TOL(4) is the tolerance to be used for checking the
          singularity of the matrices A and E when CKPROP = 'C'.
          If the user sets TOL(4) &gt; 0, then the given value of
          TOL(4) is used.  If the use