ILOG CPLEX C++ API 9.0 Reference Manual

IloCplex
This method adds con as a cut to the invoking IloCplex object. The cut is not
extracted as the regular constraints in a model, but is only copied when invoking the
method addCut. Thus, con may be deleted or modified after addCut has been called
and the change will not be notified to the invoking IloCplex object.
When columns are deleted from the extracted model, all cuts are deleted as well and
need to be reextracted if they should be considered. Cuts are not part of the root
problem, but are considered on an as-needed basis. A solution computed by IloCplex
is guaranteed to satisfy all cuts added with this method.
public const IloConstraintArray addCuts(const IloConstraintArray con)
This method adds the constraints in con as cuts to the invoking IloCplex object.
Everything said for addCut applies equally to each of the cuts given in array con.
public IloConstraint addLazyConstraint(IloConstraint con)
Note:This is an advanced method. Advanced methods typically demand a profound
understanding of the algorithms used by ILOG CPLEX. Thus they incur a higher
risk of incorrect behavior in your application, behavior that can be difficult to
debug. Therefore, ILOG encourages you to consider carefully whether you can
accomplish the same task by means of other methods instead.
This method adds con as a lazy constraint to the invoking IloCplex object. The
constraint con is copied into the lazy constraint pool; the con itself is not part of the
pool, so changes to con after it has been copied into the lazy constraint pool will not
affect the lazy constraint pool.
Lazy constraints added with addLazyConstraint are typically constraints of the
model that are not expected to be violated when left out. The idea behind this is that the
LPs that are solved when solving the MIP can be kept smaller when these constraints are
not included. IloCplex will, however, include a lazy constraint in the LP as soon as it
becomes violated. In other words, the solution computed by IloCplex makes sure that
all the lazy constraints that have been added are satisfied.
By contrast, if the constraint does not change the feasible region of the extracted model
but only strengthens the formulation, it is referred to as a user cut. While user cuts can
be added to IloCplex with addLazyConstraint, it is generally preferable to do
so with addUserCuts. It is an error, however, to add lazy constraints by means of the
method addUserCuts.
When columns are deleted from the extracted model, all lazy constraints are deleted as
well and need to be recopied into the lazy constraint pool. Use of this method in place of
addCuts allows for further presolve reductions
This method is equivalent to addCut.
ILOG CPLEX C++ API 9.0 REFERENCE M ANUAL 53