Class IloConversion

An instance of this class offers you a means to change the type of a numeric variable. For example, in a model (an instance of IloModel) extracted for an algorithm (such as an instance of the class IloCplex), you may want to convert the type of a given numeric variable (an instance of IloNumVar) from ILOFLOAT to ILOINT or to ILOBOOL (or from IloNumVar::Float to IloNumVar::Int or to IloNumVar::Bool). Such a change is known as a conversion.

After you create a conversion, you must explicitly add it to the model in order for it to be taken into account. To do so, use the member function IloModel::add or the template IloAdd. Then extract the model for an algorithm (such as an instance of IloCplex) with the member function IloAlgorithm::extract.

Multiple Type Conversions of the Same Variable

You can convert the type of a numeric variable in a model. To do so, create an instance of IloConversion and add it to the model. You can also convert the type of a numeric variable after the model has been extracted for an algorithm (such as an instance of IloCplex, documented in the ILOG CPLEX Reference Manual).

An instance of IloCplex will not accept more than one type conversion of the same variable. That is, you can change the type once, but not twice, in a single instance of IloCplex. Attempts to convert the type of the same variable more than once will throw the exception IloCplex::MultipleConversionException, documented in the ILOG CPLEX Reference Manual.

In situations where you want to change the type of a numeric variable more than once (for example, from Boolean to integer to floating-point), there are these possibilities:

• You can remove a prior conversion of a given variable in a given model. To do so, use its member function IloExtractable::end to delete it and optionally add a new conversion.
• You can apply different conversions to a given variable in more than one model, like this:

 IloNumVar x(env, 0, 10, ILOBOOL);
 IloRange rng = (x <= 10);
 IloModel mdl1(env);
 mdl1.add(rng);
 mdl1.add(IloConversion(env, x, ILOINT));
 IloCplex cplex1(mdl1);
 IloModel mdl2(env);
 mdl2.add(rng);
 mdl2.add(IloConversion(env, x, ILOFLOAT));
 IloCplex cplex2(mdl2);
 

Most member functions in this class contain assert statements. For an explanation of the macro NDEBUG (a way to turn on or turn off these assert statements), see the concept Assert and NDEBUG.

This constructor accepts a numeric variable and a type; it creates a handle to a type conversion to change the type of the variable var to the type indicated by t. You may use the parameter name to name the type conversion so that you can refer to it by a string identifier.

This constructor accepts an array of numeric variables and a type; it creates a handle to a type conversion to change the type of each variable in the array vars to the type indicated by t. You may use the parameter name to name the type conversion so that you can refer to it by a string identifier.

This constructor accepts an array of integer variables and a type; it creates a handle to a type conversion to change the type of each variable in the array vars to the type indicated by t. You may use the parameter name to name the type conversion so that you can refer to it by a string identifier.