 the upper triangular
          matrix A obtained just before the application of the
          periodic QZ algorithm (see SLICOT Library routine MB04BD).

  LDA     INTEGER
          The leading dimension of the array A.  LDA &gt;= MAX(1, N/2).

  DE      (input/output) DOUBLE PRECISION array, dimension
                         (LDDE, N/2+1)
          On entry, the leading N/2-by-N/2 lower triangular part of
          this array must contain the lower triangular part of the
          skew-symmetric matrix E