top; this is the recommended
                 option;
          = 'A': apply a more aggressive strategy, that is,
                 elements on the subdiagonal or diagonal are set
                 to zero as soon as they become smaller in magnitude
                 than eps times the norm of the corresponding
                 factor; this option is only recommended if
                 balancing is applied beforehand and convergence
                 problems are observed.

  COMPQ   CHARACTER*1
          Spec