ILOG CPLEX 11.0 User's Manual

immediately invoke populate a second time on this model, it re-uses the information itgathered in the previous invocation to begin its second phase, like this:CPLEX> populatePopulate: phase IIMIP emphasis: balance optimality and feasibility.200 32 infeasible 499.0000 512.0000 268 -2.61%300 38 infeasible 499.0000 514.0000 282 -3.01%400 44 516.0000 1 499.0000 516.0000 295 -3.41%500 48 518.0000 1 499.0000 518.0000 312 -3.81%Cover cuts applied: 2Zero-half cuts applied: 2Gomory fractional cuts applied: 1Solution pool: 40 solutions saved.Populate - Populate solution limit exceeded, integer optimal: Objective =4.9900000000e+02Solution time = 0.23 sec. Iterations = 320 Nodes = 532 (53)In this second invocation, populate does not disturb the twenty solutions alreadyaccumulated in the solution pool, and it continues to search for another twenty solutionsbefore stopping at its default limit again.The status line of both invocations of populate indicates that the optimal solution of themodel has been found. Nevertheless, populate continues to produce solutions: optimality isnot the stopping criterion for populating the solution pool. For more detail about stoppingcriteria, see Stopping Criteria for the Populate Procedure on page 309.Stopping Criteria for the Populate ProcedureOptimality is not a stopping criterion for the populate procedure. Even if the optimality gapis zero, this procedure will still try to find alternative solutions. The stopping criteria forpopulating the solution pool are these:◆Populate limit. This parameter controls how many solutions are generated before thepopulate procedure stops. Its default value is 20. Consequently, the procedure stoppedafter generating 20 solutions in the example with model location.lp in Example:Calling Populate on page 307.●●●PopulateLim in Concert TechnologyCPX_PARAM_POPULATELIM in the Callable Library (C API)mip limits populate in the Interactive OptimizerILOG CPLEX 11.0 — USER’ S MANUAL 309