A MIXED LOGARITHMIC BARRIER-AUGMENTED LAGRANGIAN ALGORITHM FOR CONSTRAINED OPTIMIZATION
Résumé
We present a primal-dual algorithm for solving a constrained optimization
problem. The method is based on a Newtonian method applied to a sequence of
perturbed KKT systems. These systems follow from a reformulation of the initial
problem under the form of a sequence of penalized problems, by introducing an
augmented Lagrangian for handling the equality constraints and a log-barrier
penalty for the inequalities. We detail the updating rules for monitoring the
different parameters (Lagrange multiplier estimates, quadratic penalty parameter
and log-barrier parameter), in order to get strong global convergence properties
and an asymptotic q-superlinear rate of convergence. We show also that the
advantage of this approach is that it introduces a natural regularization of the
linear system to solve at each iteration, when solving a degenerate problem for
which the Jacobian of constraints is rank deficient.