er of columns of A and B. N &gt;= 0.

  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
          On entry, the leading M-by-N part of this array must
          contain the matrix A.
          On exit, the leading M-by-N part of this array contains
          the matrix [ R11  R12 ] and, in the zero parts of R,
          information about the elementary reflectors used to
          compute the symplectic QR decomposition.

  LDA     INTEGER
          The leading dimension of the array A.  LD