CPLEX 11

CPLEX 11 41The solution pool relative gap parameter can also be used as a stopping criterion for the populate procedure:if populate cannot enumerate any more solutions that satisfy this objective quality, then it will stop. Inthe presence of both an absolute and a relative solution pool gap parameter, populate will stop when thesmaller of the two is reached.(default = 1e+075)solnpoolintensity (integer)Controls the trade-off between the number of solutions generated for the solution pool and the amountof time or memory consumed. This parameter applies both to MIP optimization and to the populateprocedure.Values from 1 to 4 invoke increasing effort to find larger numbers of solutions.expensive in terms of time and memory but are likely to yield more solutions.(default = 0)0 Automatic. Its default value, 0 , lets Cplex choose which intensity to apply.Higher values are more1 Mild: generate few solutions quickly. For value 1, the performance of MIP optimization is not affected.There is no slowdown and no additional consumption of memory due to this setting. However, populatewill quickly generate only a small number of solutions. Generating more than a few solutions with thissetting will be slow. When you are looking for a larger number of solutions, use a higher value of thisparameter.2 Moderate: generate a larger number of solutions. For value 2, some information is stored in the branchand cut tree so that it is easier to generate a larger number of solutions. This storage has an impacton memory used but does not lead to a slowdown in the performance of MIP optimization. With thisvalue, calling populate is likely to yield a number of solutions large enough for most purposes. Thisvalue is a good choice for most models.3 Aggressive: generate many solutions and expect performance penalty. For value 3, the algorithm ismore aggressive in computing and storing information in order to generate a large number of solutions.Compared to values 1 and 2, this value will generate a larger number of solutions, but it will slowMIP optimization and increase memory consumption. Use this value only if setting this parameter to2 does not generate enough solutions.4 Very aggressive: enumerate all practical solutions. For value 4, the algorithm generates all solutionsto your model. Even for small models, the number of possible solutions is likely to be huge; thusenumerating all of them will take time and consume a large quantity of memory.solnpoolpop (integer)Regular MIP optimization automatically adds incumbents to the solution pool as they are discovered. Cplexalso provides a procedure known as populate specifically to generate multiple solutions. You can invoke thisprocedure either as an alternative to the usual MIP optimizer or as a successor to the MIP optimizer. Youcan also invoke this procedure many times in a row in order to explore the solution space differently (seeoption solnpoolpoprepeat). In particular, you may invoke this procedure multiple times to find additionalsolutions, especially if the first solutions found are not satisfactory.(default = 1)1 Just collect the incumbents found during regular optimization2 Calls the populate proceduresolnpoolpopdel (string)After the GAMS program specified in solnpoolpoprepeat determined to continue the search for alternativesolutions, the file specified by this option is read in. The solution numbers present in this file will be deletefrom the solution pool before the populate routine is called again. The file is automatically deleted by theGAMS/Cplex link after processing.solnpoolpoprepeat (string)After the termination of the populate procedure (see option solnpoolpop). The GAMS program specifiedin this option will be called which can examine the solutions in the solution pool and can decide to run the