The solution pool feature allows you to generate and store multiple solutions to a mixed integer programming (MIP) model. This feature uses an extension of the CPLEX branch-and-cut algorithm to generate multiple solutions in addition to the optimal solution.
If your model expresses a mixed-integer problem (MIP) and generates intermediate feasible solutions, the CPLEX Studio IDE displays the pool of solutions obtained after execution at the top of the Problem Browser (see
Solution pool in the Problem Browser (scalableWarehouse.mod)). You can set a number of options (CPLEX parameters) to change how the pool is populated.
There are two ways to collect pool solutions: the default accumulation of feasible solutions over the incumbent and the explicit choice of populating the pool according to default or custom settings.
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In the default mode, any feasible solution found during the regular search by the MIP optimization algorithm is listed as a pool solution. The solution pool may contain only the incumbent solution or it may contain more. Sometimes, CPLEX finds a solution that is worse than the current incumbent. In this case, the worse solution may enter the pool although the incumbent callback is not called.
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Populate is the mode where, after the MIP search, you explicitly make the choice of finding more solutions by turning on an option that activates a special heuristic (by means of a call to the populate method).