Solve the least squares problem: \min ||A * X - B|| Using the QR factorization: \A = Q * R computed by qrDecomp.
Matrix in witch the elements on and above the diagonal of the array contain the min(M, N) x N upper trapezoidal matrix 'R' (R is upper triangular if m >= n). The elements below the diagonal, with the array tau, represent the orthogonal matrix 'Q' as product of min(m, n).
The scalar factors of the elementary reflectors