ILOG CPLEX 11.0 User's Manual

Populating the Solution PoolILOG CPLEX also provides a procedure specifically to generate multiple solutions. You caninvoke this procedure either as an alternative to the usual MIP optimizer or as a successor tothe MIP optimizer. You can also invoke this procedure many times in a row in order toexplore the solution space differently. In particular, you may invoke this procedure multipletimes to find additional solutions, especially if the first solutions found are not satisfactory.The following sections tell you more about the populate procedure:◆ Invoking the Populate Procedure on page 306◆ Algorithm of the Populate Procedure on page 306◆ Example: Calling Populate on page 307◆ Stopping Criteria for the Populate Procedure on page 309Invoking the Populate ProcedureThe populate procedure is available in all application programming interfaces (APIs) ofILOG CPLEX.◆◆◆In Concert Technology, you invoke this procedure by means of the method:●●●IloCplex::populate in the C++ API.IloCplex.populate in the Java API.Cplex.Populate in the .NET API.In the Callable Library (C API), you invoke this procedure by means of the routineCPXpopulate.In the Interactive Optimizer, you invoke this procedure by means of the commandpopulate.For examples of populating the solution pool in an application, seeyourCPLEXinstallation/examples/src/populate.c and ilopopulate.cpp aswell as Populate.java and Populate.cs.Algorithm of the Populate ProcedureBriefly, the algorithm that populates the solution pool works in two phases.In the first phase, it solves the model to optimality (or some stopping criterion set by theuser) while it sets up a search tree for the second phase.In the second phase, it generates multiple solutions by using the information computed andstored in the first phase and by continuing to explore the tree.306 ILOG CPLEX 11.0 — USER’ S MANUAL