What Belongs in an Application to Refine Conflict

ILOG CPLEX 11.0 User's Manual > Infeasibility and Unboundedness > Diagnosing Infeasibility by Refining Conflicts > Using the Conflict Refiner in an Application > What Belongs in an Application to Refine Conflict

What Belongs in an Application to Refine Conflict

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There are a few remarks to make about that modification:

Lazy constraints must not be present in a conflict.
User-defined cuts (also known as user cuts) must not be present in a conflict.

These lines check for lazy constraints and user-defined cuts.

 if ( lazy.getSize() || cuts.getSize() ) {
           cout << "Lazy Constraints and User Cuts ignored" << endl;
 }

Since it makes little sense to modify the bounds of binary (0-1) variables, this example does not include them in a conflict. This line eliminates binary variables from consideration:
if ( var[i].getType() != IloNumVar::Bool ) {

Eliminating binary variables from consideration produces behavior consistent with behavior of the Interactive Optimizer. Doing so is optional. If you prefer for the conflict refiner to work on the bounds of your binary variables as well, omit this test, bearing in mind that it may take much longer to refine your model to a minimal conflict in that case.

The method useDetailedDisplay is included to improve readability of the conflict when it is displayed.

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