:N,M-N+1), if M &gt;= N, or of B(N-M+1:N,1:M), if M &lt; N,
          contains the upper triangular matrix R (as defined in
          METHOD), and the remaining elements (below the diagonal
          of R) together with the elements of the array TAU are
          overwritten by details of the matrix P (also defined in
          METHOD). When M &lt; N, rows 1,...,(N-M) of the array B
          are overwritten by the matrix Z (see METHOD).

  LDB     INTEGER
          The leading dimension of array B.
       