/// <summary>
/// Returns the sum of the weights of all items in the backpack of the inhabitant.
/// </summary>
/// <param name="inhabitant"></param>
/// <returns></returns>
public double GetWeight(Inhabitant inhabitant)
{
double weight = 0.0;
for (uint i = 0; i < Size; i++)
weight += element_array[i].Weight * (inhabitant.GetChromosome()[i] ? 1.0 : 0.0);
return weight;
}
public static void Mutation(ref Inhabitant individual)
{
Random rnd = new Random();
for(uint i = 0; i < individual.ChromosomeLength; i++)
if (rnd.NextDouble() > 0.95)
individual.SetGen(!individual.GetGen(i), i);
}
/// <summary>
/// Returns the sum of the values of all items in the backpack of the inhabitant.
/// </summary>
/// <param name="inhabitant"></param>
/// <returns></returns>
public double GetValue(Inhabitant inhabitant)
{
double value = 0.0;
for (uint i = 0; i < Size; i++)
value += element_array[i].Value * (inhabitant.GetChromosome()[i] ? 1.0 : 0.0);
return value;
}
public void PrintElementsInBackpack(Inhabitant inhabitant)
{
for(uint i = 0; i < Size; i++)
{
if (inhabitant.GetGen(i))
{
Console.WriteLine("\n\nName: {0}\nValue: {1}\nWeight: {2}", element_array[i].Name,
element_array[i].Value, element_array[i].Weight);
}
}
}
/// <summary>
/// Begin the whole population with random values.
/// </summary>
public void BeginPopulation()
{
Random rnd;
Stock Items;
Items = new Stock();
rnd = new Random();
for (uint i = 0; i < this.Size; i++)
{
Boolean[] new_chromosome;
new_chromosome = new Boolean[this.chromosome_length];
for (uint j = 0; j < this.chromosome_length; j++)
new_chromosome[j] = rnd.Next() % 2 == 0;
Individual[i] = new Inhabitant(new_chromosome);
//Setting values for fitness, value and weight.
Individual[i].Value = Items.GetValue(Individual[i]);
Individual[i].Weight = Items.GetWeight(Individual[i]);
Individual[i].Fitness = Items.GetFitness(Individual[i]);
}
//Getting the sum of the fitness of the whole population.
total_fitness = Individual.Sum(i => i.Fitness);
}
/// <summary>
/// Set an inhabitant in the given position.
/// </summary>
/// <param name="inhabitant"></param>
/// <param name="position"></param>
public void SetInhabitant(Inhabitant inhabitant, uint position)
{
Individual[position] = inhabitant;
}
/// <summary>
/// Returns the fitness of the inhabitant. It works as evaluation function.
/// To use this function, you should have already got the value and weight of the inhabitant.
/// </summary>
/// <param name="inhabitant"></param>
/// <returns></returns>
public double GetFitness(Inhabitant inhabitant)
{
return inhabitant.Value / total_value * (inhabitant.Weight > Max_Weight ? 0.2 : 1.0);
}