L', need not be set to zero,
          and are not referenced if DICO = 'D'.
          On exit, the leading N-by-N part of this array contains
          the following matrix product
             alpha*T'*T*A, if TRANS = 'N', or
             alpha*A*T*T', otherwise,
          if DICO = 'C', or
             T*A, if TRANS = 'N', or
             A*T, otherwise,
          if DICO = 'D' (and in this case, these products have a
          Hessenberg form, if HESS = 'H').

  LDA     INTEGER
          The leading dim