,1)/norm(S(s,s),1) )                (1)
          has the smallest value, for the threshold values used,
          where A(s,s) and B(s,s) are the scaled submatrices.
          If THRESH = -2, the norm ratio reduction (1) is tried, but
          the subroutine may return IWARN = 1 and reset the scaling
          factors to 1, if this seems suitable. See the description
          of the argument IWARN and FURTHER COMMENTS.
          If THRESH = -3, the condition is that
             norm(A(s,s),1)*norm(B(s,s