ILOG CPLEX C++ API 9.0 Reference Manual

IloCplex::HeuristicCallbackI
Inherited methods from IloCplex::CallbackI
CallbackI::abort, CallbackI::duplicateCallback, CallbackI::getEnv,
CallbackI::getModel, CallbackI::getNcols, CallbackI::getNQCs,
CallbackI::getNrows, CallbackI::main
Description
See Also
Methods
An instance of the class IloCplex::HeuristicCallbackI represents a userwritten
callback in an application that uses an instance of IloCplex to solve a mixed
integer programming problem (a MIP). When you derive a user-defined class of
callbacks, this class offers protected methods for you to:
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give the instance of IloCplex a potential new incumbent solution;
query the instance of IloCplex about the solution status for the current node;
query the instance of IloCplex about the variable bounds at the current node;
change bounds temporarily on a variable or group of variables at the current node;
re-solve the problem at the node with the changed bounds;
◆ use all the query functions inherited from parent classes.
In short, this callback allows you to attempt to construct an integer feasible solution at a
node and pass it to the invoking instance of IloCplex to use as its new incumbent.
The API supports you in finding such a solution by allowing you iteratively to change
bounds of the variables and re-solve the node relaxation. Changing the bounds in the
heuristic callback has no effect on the search beyond the termination of the callback.
The heuristic callback is called after the node relaxation has been solved (including all
cuts that may have been generated).
If an attempt is made to access information not available at the node for the invoking
instance of IloCplex, an exception is thrown.
IloCplex, IloCplex::Callback, IloCplex::CallbackI,
IloCplex::ControlCallbackI, IloCplex::MIPCallbackI,
ILOHEURISTICCALLBACK0
protected IloCplex::CplexStatus getCplexStatus()
This method returns the ILOG CPLEX status of the instance of IloCplex at the
current node (that is, the state of the optimizer at the node) during the last call to solve
(which may have been called directly in the callback or by IloCplex when processing
the node).
The enumeration IloCplex::CplexStatus lists the possible status values.
ILOG CPLEX C++ API 9.0 REFERENCE M ANUAL 153