ILOG CPLEX C++ API 9.0 Reference Manual

IloCplex::BranchCallbackI
NodeData * data)
For a branch specified by only one variable, this method offers the same facilities as
IloCplex::BranchCallbackI::makeBranch for a branch specified by a set
of variables.
protected NodeId makeBranch(const IloNumVar var,
IloNum bound,
IloCplex::BranchDirection dir,
IloNum objestimate,
NodeData * data)
For a branch specified by only one variable, this method offers the same facilities as
IloCplex::BranchCallbackI::makeBranch for a branch specified by a set
of variables.
protected NodeId makeBranch(const IloIntVarArray vars,
const IloNumArray bounds,
const IloCplex::BranchDirectionArray dirs,
IloNum objestimate,
NodeData * data)
This method overrides the branch chosen by an instance of IloCplex. A method
named makeBranch can be called zero, one, or two times in every invocation of the
branch callback. If you call it once, it creates one node; it you call it twice, it creates two
nodes (one node at each call). If you call it more than twice, it throws an exception.
Each call specifies a branch; in other words, it instructs the invoking IloCplex object
how to create a subnode from the current node by specifying new, tighter bounds for a
set of variables.
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The parameter vars contains the variables for which new bounds will be set in the
branch.
The parameter bounds contains the new bounds for the variables listed in vars;
that is, bounds[j] is the new bound to be set for vars[j].
◆ The parameter dirs indicates the branching direction for the variables in vars.
dir[j] == IloCplex::BranchUp
means that bounds[j] specifies a lower bound for vars[j].
dirs[j] == IloCplex::BranchDown
means that bounds[j] specifies an upper bound for vars[j].
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The parameter objestimate provides an estimate of the resulting optimal
objective value for the subnode specified by this branch. The invoking instance of
IloCplex may use this estimate to select nodes to process. Providing a wrong
estimate will not influence the correctness of he solution, but it may influence
performance. Using the objective value of the current node is usually a safe choice.
ILOG CPLEX C++ API 9.0 REFERENCE M ANUAL 90