Class IloCplex::MIPInfoCallbackI

An instance of the class IloCplex::MIPInfoCallbackI represents a user-written callback in an application that uses an instance of IloCplex to solve a mixed integer program (MIP). IloCplex calls the user-written callback regularly during the branch & cut search.

User-written callbacks of this class are compatible with MIP dynamic search.

This class offers methods for accessing an incumbent solution and its objective value from a user-written callback. It also offers methods for accessing priority orders and progress information, such as the number of nodes solved.

The methods of this class are protected for use in deriving a user-written callback class and in implementing the main method there.

If an attempt is made in a user-written callback to access information not available to an instance of this class, an exception is raised. For example, if there is no incumbent, the methods that query about incumbents will throw an exception.

This class also provides the common application programming interface (API) for these callback classes:

• IloCplex::DisjunctiveCutInfoCallbackI
• IloCplex::FlowMIRCutInfoCallbackI
• IloCplex::FractionalCutInfoCallbackI
• IloCplex::ProbingInfoCallbackI

This constructor creates a callback for use in an application that uses an instance of IloCplex to solve a mixed integer program (MIP).

This method returns the currently best known bound on the optimal solution value of the problem at the time the invoking callback is called by an instance of IloCplex while solving a MIP. When a model has been solved to optimality, this value matches the optimal solution value. Otherwise, this value is computed for a minimization (maximization) problem as the minimum (maximum) objective function value of all remaining unexplored nodes.

An instance of IloCplex uses the cutoff value (the value of the objective function of the subproblem at a node in the search tree) to decide when to prune nodes from the search tree (that is, when to cut off that node and discard the nodes beyond it). The cutoff value is updated whenever a new incumbent is found.

This method returns the branch direction previously assigned to variable var with method IloCplex::setDirection or IloCplex::setDirections. If no direction has been assigned, IloCplex::BranchGlobal will be returned.

This method returns the branch direction previously assigned to variable var with method IloCplex::setDirection or IloCplex::setDirections. If no direction has been assigned, IloCplex::BranchGlobal will be returned.

Returns the value of the objective function of the incumbent solution (that is, the best integer solution found so far) at the time the invoking callback is called by an instance of IloCplex while solving a MIP. If there is no incumbent, this method throws an exception.

This method returns the slack value for the range specified by rng for the incumbent. If there is no incumbent, this method throws an exception.

This method puts the slack value for each range in the array of ranges cons into the corresponding element of the array vals for the incumbent. CPLEX resizes array vals to match the size of array cons. If there is no incumbent, this method throws an exception.

Returns the solution value of var in the incumbent solution at the time the invoking callback is called by an instance of IloCplex while solving a MIP. If there is no incumbent, this method throws an exception.

Returns the solution value of var in the incumbent solution at the time the invoking callback is called by an instance of IloCplex while solving a MIP. If there is no incumbent, this method throws an exception.

Returns the value of each variable in the array vars with respect to the current incumbent solution, and it puts those values into the corresponding array vals. If there is no incumbent, this method throws an exception.

Returns the value of each variable in the array vars with respect to the current incumbent solution, and it puts those values into the corresponding array vals. If there is no incumbent, this method throws an exception.

Returns the identifier of the parallel thread being currently executed. This number is between 0 (zero) and the value returned by the method getUserThreads()-1.

This method returns a nonzero value only for the class IloCplex::MIPCallbackI and its subclasses. In other words, this method is valid only for query, diagnostic, and control callbacks. It is not valid for informational callbacks.

Returns the total number of iterations executed so far during the current optimization to solve the node relaxations.

Returns the number of nodes already processed in the current optimization.

Returns the number of nodes left to explore in the current optimization.

Returns the branch priority used for variable var in the current optimization.

Returns the branch priority used for variable var in the current optimization.

Returns IloTrue if an integer feasible solution has been found, or, equivalenty, if an incumbent solution is available at the time the invoking callback is called by an instance of IloCplex while solving a MIP.