ILOG CPLEX 11.0 User's Manual

◆ If you want to filter solutions based on their validity in an additional linear constraint,use a range filter, as explained in Range Filters on page 325.Those two ways are practical for most purposes. However, if you require finer control ofwhich solutions to keep and which to eliminate, use an incumbent callback, as explained inIncumbent Callback as a Filter on page 328.Adding or deleting filters does not affect the solutions already in the pool; new filters areapplied only at the next call of MIP optimization or the populate procedure.Filters are assigned an index number when they are added to the solution pool, and they maybe accessed through this index number. Diversity filters and range filters share the samesequence of indices.To count the number of filters associated with the solution pool, use one of these methods,routines, or commands:◆In Concert Technology●●●IloCplex::getNfilters in the C++ API;IloCplex.getNFilters in the Java API;Cplex.GetNFilters in the .NET API.◆ CPXgetsolnpoolnumfilters in the Callable Library (C API );To access a filter, use one of these methods, routines, or commands:◆Concert Technology offers a method to access each characteristic of a filter; for example,getFilterType, getFilterIndex, getFilterVars, and so forth.◆ CPXgetsolnpoolrngfilter or CPXgetsolnpooldivfilter in the C API;To delete a filter, use one of these methods, routines, or commands:◆In Concert Technology●●In the C++ API, use the method IloCplex::delFilter.In the Java API, use the method IloCplex.delFilter.● In the .NET API, use the method Cplex.DelFilter.◆ In the Callable Library (C API), use CPXdelsolnpoolfilters .◆ In the Interactive Optimizer, use the command change delete filter.Diversity FiltersA diversity filter allows you generate solutions that are similar to (or different from) a set ofreference values that you specify for a set of binary variables. In particular, you can use adiversity filter to generate more solutions that are similar to an existing solution or to an324 ILOG CPLEX 11.0 — USER’ S MANUAL