/**
* Runs of the GDE3 algorithm.
* @return a <code>SolutionSet</code> that is a set of non dominated solutions
* as a result of the algorithm execution
* @throws JMException
*/
public override SolutionSet Execute()
{
int populationSize = -1;
int maxIterations = -1;
int evaluations;
int iterations;
SolutionSet population;
SolutionSet offspringPopulation;
Distance distance;
IComparer <Solution> dominance;
Operator selectionOperator;
Operator crossoverOperator;
distance = new Distance();
dominance = new DominanceComparator();
Solution[] parent;
//Read the parameters
JMetalCSharp.Utils.Utils.GetIntValueFromParameter(this.InputParameters, "populationSize", ref populationSize);
JMetalCSharp.Utils.Utils.GetIntValueFromParameter(this.InputParameters, "maxIterations", ref maxIterations);
selectionOperator = this.Operators["selection"];
crossoverOperator = this.Operators["crossover"];
//Initialize the variables
population = new SolutionSet(populationSize);
evaluations = 0;
iterations = 0;
// Create the initial solutionSet
Solution newSolution;
for (int i = 0; i < populationSize; i++)
{
newSolution = new Solution(this.Problem);
this.Problem.Evaluate(newSolution);
this.Problem.EvaluateConstraints(newSolution);
evaluations++;
population.Add(newSolution);
}
// Generations ...
while (iterations < maxIterations)
{
// Create the offSpring solutionSet
offspringPopulation = new SolutionSet(populationSize * 2);
for (int i = 0; i < populationSize; i++)
{
// Obtain parents. Two parameters are required: the population and the
// index of the current individual
parent = (Solution[])selectionOperator.Execute(new object[] { population, i });
Solution child;
// Crossover. Two parameters are required: the current individual and the
// array of parents
child = (Solution)crossoverOperator.Execute(new object[] { population.Get(i), parent });
this.Problem.Evaluate(child);
this.Problem.EvaluateConstraints(child);
evaluations++;
// Dominance test
int result;
result = dominance.Compare(population.Get(i), child);
if (result == -1)
{ // Solution i dominates child
offspringPopulation.Add(population.Get(i));
}
else if (result == 1)
{ // child dominates
offspringPopulation.Add(child);
}
else
{ // the two solutions are non-dominated
offspringPopulation.Add(child);
offspringPopulation.Add(population.Get(i));
}
}
// Ranking the offspring population
Ranking ranking = new Ranking(offspringPopulation);
int remain = populationSize;
int index = 0;
SolutionSet front = null;
population.Clear();
// Obtain the next front
front = ranking.GetSubfront(index);
while ((remain > 0) && (remain >= front.Size()))
{
//Assign crowding distance to individuals
distance.CrowdingDistanceAssignment(front, this.Problem.NumberOfObjectives);
//Add the individuals of this front
for (int k = 0; k < front.Size(); k++)
{
population.Add(front.Get(k));
} // for
//Decrement remain
remain = remain - front.Size();
//Obtain the next front
index++;
if (remain > 0)
{
front = ranking.GetSubfront(index);
}
}
// remain is less than front(index).size, insert only the best one
if (remain > 0)
{ // front contains individuals to insert
while (front.Size() > remain)
{
distance.CrowdingDistanceAssignment(front, this.Problem.NumberOfObjectives);
front.Remove(front.IndexWorst(new CrowdingComparator()));
}
for (int k = 0; k < front.Size(); k++)
{
population.Add(front.Get(k));
}
remain = 0;
}
iterations++;
}
// Return the first non-dominated front
Ranking rnk = new Ranking(population);
this.Result = rnk.GetSubfront(0);
return(this.Result);
}
