The OPTLP Procedure

Iteration Log for the Interior Point Solver

The interior point solver implements an infeasible primal-dual predictor-corrector interior point algorithm. The following information is displayed in the iteration log:


indicates the iteration number.


indicates the (absolute) complementarity.

Duality Gap

indicates the (relative) duality gap.

Primal Infeas

indicates the (relative) primal infeasibility measure.

Bound Infeas

indicates the (relative) bound infeasibility measure.

Dual Infeas

indicates the (relative) dual infeasibility measure.

If the sequence of solutions converges to an optimal solution of the problem, you should see all columns in the iteration log converge to zero or very close to zero. If they do not, it can be the result of insufficient iterations being performed to reach optimality. In this case, you might need to increase the value specified in the MAXITER= or MAXTIME= options. If the complementarity or the duality gap do not converge, the problem might be infeasible or unbounded. If the infeasibility columns do not converge, the problem might be infeasible.