e
          (N/2-1)-by-(N/2-1) upper triangular part of the submatrix
          in the columns 3 to N/2+1 of this array contains the
          strictly upper triangular part of the skew-symmetric
          matrix D (without the main diagonal) just before the
          application of the periodic QZ algorithm.

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

  B       (input/output) DOUBLE PRECISION array, dimension
                         (LDB, N/2)
   