When solving an LP or QP, all the algorithms also compute dual solution information that your application can then query. (However, no dual information is available for QCP models.) You can access reduced costs by calling the method IloCplex.getReducedCost or IloCplex.getReducedCosts. Similarly, you can access dual solution values for the ranged constraints of the active model by using the methods IloCplex.getDual or IloCplex.getDuals.