ILOG CPLEX 11.0 User's Manual

C H A P T E R28User-Cut and Lazy-Constraint PoolsIn contrast to the cuts that ILOG CPLEX may automatically add while solving a problem,user cuts are those cuts that a user defines based on information already implied about theproblem by the constraints; user cuts may not be strictly necessary to the problem, but theytighten the model. Lazy constraints are constraints that the user knows are unlikely to beviolated, and in consequence, the user wants them applied lazily, that is, only as necessary ornot before needed. User cuts can be grouped together in a pool of user cuts. Likewise, lazyconstraints can also be grouped into a pool of lazy constriants. This chapter covers thosetopics.◆ What Are Pools of User Cuts or Lazy Constraints? on page 420◆ Adding User Cuts and Lazy Constraints on page 422◆ Deleting User Cuts and Lazy Constraints on page 425Important: Only linear constraints may be included in a pool of user cuts or lazyconstraints. Neither user cuts nor lazy constraints may contain quadratic terms.ILOG CPLEX 11.0 — USER’ S MANUAL 419