ILOG CPLEX 11.0 User's Manual > Discrete Optimization > Using Column Generation: a Cutting Stock Example > Developing the Model: Building and Modifying > Changing the Type of a Variable

After the column-generation phase terminates, an integer solution to the master problem must be found. To do so, the type of the variables must be changed from continuous to integer.

With Concert Technology, in order to change the type of a variable in a model, you actually create an extractable object (an instance of IloConversion) and add that object to the model.

In the example, when the application needs to change the elements of Cut (an array of numeric variables) from their default type of ILOFLOAT to integer (type ILOINT), it creates an instance of IloConversion for the array Cut, and adds the conversion to the model, cutOpt, like this:

cutOpt.add(IloConversion(env, Cut, ILOINT));