On the computer-algebra implementation of the least-squares method on the nonnegative orthant

Maple procedures for solving the so-called NNLS (Nonnegative Least Squares) problem are described. The NNLS problem is to minimize
$$ ||Ex-f||_2 $$
subject to
$$ x\geqslant0. $$
The solution of an NNLS problem is the crucial step OF the conventional algorithm for solving linear least-squares problems with linear inequality constraints.