In order to be able to search for solutions, CP Optimizer (or an instance of IloCP) must save certain information, including the state of objects such as:

• the values of all the CP Optimizer variables associated with that search,
• the domains of all the CP Optimizer variables associated with that search,
• all the constraints that have been posted on the variables associated with that search.

The state of a CP Optimizer search also includes memory usage, object values, any search space already explored, and so on.

States are used during the search for a solution. The most important feature of states is that they can be restored.

In other words, during the execution of a CP Optimizer program, a state can be created, then execution proceeds, then that previously created state may be restored. In such a case, we say that CP Optimizer backtracks to the previously created state.

See the concepts Choice point in CP Optimizer, Propagation in CP Optimizer, and Reversibility in CP Optimizer for more information.

See also

IlcConstraint