Class IloComparator<>

A comparator is a class that implements a comparison between two objects. IloComparator is a template class, meaning that it can be instantiated to define a comparator for user-defined classes.

A comparator can be constructed from a single evaluator (see member functions IloEvaluator::makeLessThanComparator, IloEvaluator::makeGreaterThanComparator), from a composition of evaluators (IloLexicographicComparator, IloParetoComparator), or by using macros (ILOCOMPARATOR0 and ILOCLIKECOMPARATOR0).

There are two main comparison functions of a comparator: operator() and isBetterThan.

The function operator() takes two objects, o1 and o2, and by default returns -1, 0, or 1 depending on whether o1 is respectively better, equal or worse than o2. The optional argument nu is a context that can be used for the comparison:

 IloInt operator()(IloObject o1, IloObject o2, IloAny nu = 0) const;
 

The function isBetterThan takes two objects, o1 and o2, and returns IloTrue if and only if o1 is preferred to o2. The optional argument nu is a context that can be used for the comparison:

 IloBool isBetterThan(IloObject o1, IloObject o2, IloAny nu = 0) const;
 

It is possible to combine comparators and evaluators into more complicated comparators. See IloLexicographicComparator and IloParetoComparator.

For more information, see Selectors.

This member function returns IloTrue if and only if the the left-hand side object left is better than or equal to the right-hand side object right. The parameter nu is a context that will be passed to the evaluator(s) of the comparator.

This member function returns IloTrue if and only if the the left-hand side object left is better than the right-hand side object right. The parameter nu is a context that will be passed to the evaluator(s) of the comparator.

This member function returns IloTrue if and only if the the left-hand side object left is equal to the right-hand side object right. The parameter nu is a context that will be passed to the evaluator(s) of the comparator.

This member function returns IloTrue if and only if the the left-hand side object left is worse than or equal to the right-hand side object right. The parameter nu is a context that will be passed to the evaluator(s) of the comparator.

This member function returns IloTrue if and only if the the left-hand side object left is worse than the right-hand side object right. The parameter nu is a context that will be passed to the evaluator(s) of the comparator.

This member function returns a comparator that inverts the sense of the invoking comparator. The returned comparator interchanges the objects to be compared.

This member function implements the comparison of two objects based on the evaluator with which the invoking comparator was created and based on the sense of comparison of the invoking comparator. This member function returns -1, 0, or 1 depending on whether object left is considered to be better, equal, or worse than object right. The parameter nu is a context that will be passed to the evaluator(s) of the comparator.