private String retrieveBestIndividual(Set <String> population,
FitnessFunction fitnessFn)
{
String bestIndividual = null;
double bestSoFarFValue = Double.NEGATIVE_INFINITY;
foreach (String individual in population)
{
double fValue = fitnessFn.getValue(individual);
if (fValue > bestSoFarFValue)
{
bestIndividual = individual;
bestSoFarFValue = fValue;
}
}
return(bestIndividual);
}
private String randomSelection(Set <String> population,
FitnessFunction fitnessFn)
{
String selected = null;
// Determine all of the fitness values
double[] fValues = new double[population.Count];
String[] popArray = population.toArray(new String[population.Count]);
for (int i = 0; i < popArray.length; i++)
{
fValues[i] = fitnessFn.getValue(popArray[i]);
}
// Normalize the fitness values
fValues = Util.normalize(fValues);
double prob = random.nextDouble();
double totalSoFar = 0.0;
for (int i = 0; i < fValues.length; i++)
{
// Are at last element so assign by default
// in case there are rounding issues with the normalized values
totalSoFar += fValues[i];
if (prob <= totalSoFar)
{
selected = popArray[i];
break;
}
}
// selected may not have been assigned
// if there was a rounding error in the
// addition of the normalized values (i.e. did not total to 1.0)
if (null == selected)
{
// Assign the last value
selected = popArray[popArray.length - 1];
}
return(selected);
}
private String retrieveBestIndividual(Set<String> population,
FitnessFunction fitnessFn)
{
String bestIndividual = null;
double bestSoFarFValue = Double.NEGATIVE_INFINITY;
foreach (String individual in population)
{
double fValue = fitnessFn.getValue(individual);
if (fValue > bestSoFarFValue)
{
bestIndividual = individual;
bestSoFarFValue = fValue;
}
}
return bestIndividual;
}
private String randomSelection(Set<String> population,
FitnessFunction fitnessFn)
{
String selected = null;
// Determine all of the fitness values
double[] fValues = new double[population.Count];
String[] popArray = population.toArray(new String[population.Count]);
for (int i = 0; i < popArray.length; i++)
{
fValues[i] = fitnessFn.getValue(popArray[i]);
}
// Normalize the fitness values
fValues = Util.normalize(fValues);
double prob = random.nextDouble();
double totalSoFar = 0.0;
for (int i = 0; i < fValues.length; i++)
{
// Are at last element so assign by default
// in case there are rounding issues with the normalized values
totalSoFar += fValues[i];
if (prob <= totalSoFar)
{
selected = popArray[i];
break;
}
}
// selected may not have been assigned
// if there was a rounding error in the
// addition of the normalized values (i.e. did not total to 1.0)
if (null == selected)
{
// Assign the last value
selected = popArray[popArray.length - 1];
}
return selected;
}
