# Gradient projection method

### From Glossary

A feasible direction method by projecting the gradient into the working surface,
. Suppose has full row rank. Then,
projects any vector into the null space of :
for all . The form of an iteration is ,
where is the projected gradient, , and is determined by
line search. Since , , thus staying in
the working surface. (This extends to nonlinear constraints by using the same correction procedure as the
generalized reduced gradient method.)