A widely used and successful approach to solving constrained optimization problems, that is
where
F(
x) is a given objective function of
n real variables, subject to the
t nonlinear constraints on the variables,
Inequality constraints are also possible. A solution of this problem is also a stationary point (a point at which all the partial derivatives vanish) of the related function of
x and λ,
A quadratic approximation to this function is now constructed that along with linearized constraints forms a quadratic programming problem – i.e., the minimization of a function quadratic in the variables, subject to linear constraints. The solution of the original optimization problem, say
x*, is now obtained from an initial estimate and solving a sequence of updated quadratic programs; the solutions of these provide improved approximations, which under certain conditions converge to
x*.