The GA Procedure
- Overview
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Getting Started
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SyntaxPROC GA StatementContinueFor CallCross CallDynamic_array CallEvaluateLC CallGetDimensions CallGetObjValues CallGetSolutions CallInitialize CallMarkPareto CallMutate CallObjective FunctionPackBits CallProgramming StatementsReadChild CallReadCompare CallReadMember CallReadParent CallReEvaluate CallSetBounds CallSetCompareRoutine CallSetCross CallSetCrossProb CallSetCrossRoutine CallSetElite CallSetEncoding CallSetFinalize CallSetMut CallSetMutProb CallSetMutRoutine CallSetObj CallSetObjFunc CallSetProperty CallSetSel CallSetUpdateRoutine CallShellSort CallShuffle CallUnpackBits FunctionUpdateSolutions CallWriteChild CallWriteMember Call
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DetailsUsing Multisegment EncodingUsing Standard Genetic Operators and Objective FunctionsDefining a User Fitness Comparison RoutineDefining User Genetic OperatorsDefining a User Update RoutineDefining an Objective FunctionDefining a User Initialization RoutineSpecifying the Selection StrategyIncorporating Heuristics and Local OptimizationsHandling ConstraintsOptimizing Multiple Objectives
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Examples
- References
call SetElite ( elite ) ;
The SetElite call sets the number of best solutions to pass to the next generation. The input to the SetElite subroutine is as follows:
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elite |
is the number of best solutions to be passed unmodified from the current solution generation to the next. |
The SetElite subroutine is used to ensure that the best solutions encountered in the optimization are not lost by the random selection process. In pure tournament selection, although better solutions are more likely to be selected, it is also possible that any given solution will not be chosen to participate in a tournament, and even if it is selected, it might be modified by crossover or mutation. The SetElite call modifies the optimization process such that the best elite solutions in the current population are exactly preserved and passed on to the next generation. This behavior is observed regardless of the crossover or mutation settings. When a SetElite call is made, the first elite solutions in the population retrieved by a GetSolutions call or output to a data set are the fittest, and these elite solutions are sorted so that the most fit is first. In general, using the SetElite call speeds the convergence of the optimization process. However, it can also lead to premature convergence before a true global optimum is reached. If no SetElite call is made, a default elite value of 1 is used by the GA procedure to make sure that the best solution encountered in the optimization process is never lost.