E:/Projects/Visual Studio/CSharp/GEP .NET Framework/GEP.Core/Common/GeneticOperators/GenotypeSelection/Fittest.cs

Go to the documentation of this file.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace GEP.Core.Common.GeneticOperators.GenotypeSelection
{
    [Serializable]
    public class Fittest : GenotypeSelection
    {
        protected int _selectionSize;
        protected int[][] _selection;

        public Fittest(int selectionSize)
        {
            _selectionSize = selectionSize;
            _selection = new int[1][];
            _selection[0] = new int[selectionSize];
        }

        public int[][] Select(ref int selectionStartIndex, ref int selectionEndIndex, Population population)
        {
            Select(population);
            selectionStartIndex = 0;
            selectionEndIndex = 0;
            return _selection;
        }

        public int[][] Select(Population population)
        {
            double optimalFitness;
            double lastOptimalFitness =
                (population._operators._matingProbabilityFunction._fitnessCloserToZeroIsBetter ? 0 : double.MaxValue);
            int optimalIndex = 0;
            bool isSelected;
            for (int i = 0; i < _selectionSize; i++)
            {
                optimalFitness =
                    (population._operators._matingProbabilityFunction._fitnessCloserToZeroIsBetter ? double.MaxValue : 0);
                for (int j = 0; j < population.Size; j++)
                {
                    if (population[j]._fitness == lastOptimalFitness)
                    {
                        isSelected = false;
                        for (int k = 0; k < i; k++)
                        {
                            if (j == _selection[0][k])
                                isSelected = true;
                        }
                        if (!isSelected)
                        {
                            optimalIndex = j;
                            optimalFitness = lastOptimalFitness;
                            break;
                        }
                    }
                    if (population._operators._matingProbabilityFunction._fitnessCloserToZeroIsBetter)
                    {
                        if (population[j]._fitness > lastOptimalFitness)
                        {
                            if (population[j]._fitness < optimalFitness)
                            {
                                optimalIndex = j;
                                optimalFitness = population[j]._fitness;
                            }
                        }
                    }
                    else
                    {
                        if (population[j]._fitness < lastOptimalFitness)
                        {
                            if (population[j]._fitness > optimalFitness)
                            {
                                optimalIndex = j;
                                optimalFitness = population[j]._fitness;
                            }
                        }
                    }
                }
                _selection[0][i] = optimalIndex;
                lastOptimalFitness = optimalFitness;
            }
            return _selection;
        }
    }
}

GEP .NET Framwork Main Page