/// <summary>
/// Compute the fitness measure by passing the
/// given parameters to the wrapped problem, and if
/// candidate solution is an improvement then log
/// the results.
/// </summary>
/// <param name="parameters">Candidate solution.</param>
/// <param name="fitnessLimit">Preemptive Fitness Limit</param>
/// <param name="newFeasible">Feasibility of old candidate solution.</param>
/// <param name="oldFeasible">Feasibility of new candidate solution.</param>
/// <returns>Fitness value.</returns>
public override double Fitness(double[] parameters, double fitnessLimit, bool oldFeasible, bool newFeasible)
{
double fitness = Problem.Fitness(parameters, fitnessLimit, oldFeasible, newFeasible);
// Log solutions. If feasibiilty is required then only log feasible solutions.
if (!OnlyFeasible || newFeasible)
{
// Log solutions with better fitness and feasibility.
if (Tools.BetterFeasibleFitness(oldFeasible, newFeasible, fitnessLimit, fitness))
{
// Ensure log does not exceed desired capacity.
if (Log.Count >= Capacity)
{
// Assume log is sorted in ascending (worsening) order.
// Remove worst from the log.
Log.RemoveAt(Log.Count - 1);
}
Solution candidateSolution = new Solution(parameters, fitness, newFeasible);
// Add new solution to the log.
Log.Add(candidateSolution);
// Sort log according to fitness.
// This could be implemented more efficiently
// but it is not crucial for runtime performance
// so this simple implementation is sufficient.
Log.Sort(new Solution.FitnessComparer());
}
}
return fitness;
}
/// <summary>
/// Compute the fitness measure by passing the
/// given parameters to the wrapped problem, and if
/// candidate solution is an improvement then log
/// the results.
/// </summary>
/// <param name="parameters">Candidate solution.</param>
/// <param name="fitnessLimit">Preemptive Fitness Limit</param>
/// <returns>Fitness value.</returns>
public override double Fitness(double[] parameters, double fitnessLimit)
{
double fitness = Problem.Fitness(parameters, fitnessLimit);
if (fitness < fitnessLimit)
{
Solution candidateSolution = new Solution(parameters, fitness);
// Add new solution to the log.
_log.Add(fitness, candidateSolution);
if (Log.Count > Capacity)
{
// Remove worst from the log.
_log.RemoveAt(Log.Count - 1);
}
}
return fitness;
}
