/// <summary>
/// Assign a species to each network in the population
/// </summary>
private void AssignPopulationToSpecies()
{
foreach (NeatNetwork network in population)
{
// Attempt to add an existing species
bool added = false;
foreach (NeatSpecies species in activeSpecies)
{
added = species.AttemptAdd(network);
if (added)
{
break;
}
}
// Create a new species with this as a rep
if (!added)
{
NeatSpecies newSpecies = new NeatSpecies(this, network);
activeSpecies.Add(newSpecies);
}
}
// Remove species with no currently active members
for (int i = 0; i < activeSpecies.Count; ++i)
{
if (activeSpecies[i].population.Count == 0)
{
Debug.Log("Species (" + activeSpecies[i].colour.ToString() + ") has died after " + activeSpecies[i].generationsLived + " generations");
activeSpecies.RemoveAt(i);
--i;
}
}
}
/// <summary>
/// Create the next generation of networks
/// </summary>
/// <param name="newPopulationSize">How large the next population should be</param>
/// <returns></returns>
public NeatNetwork[] BreedNextGeneration(int newPopulationSize)
{
SaveXML();
// Calulate the average adjusted fitness
float totalFitness = 0.0f;
Dictionary <NeatSpecies, float> fitness = new Dictionary <NeatSpecies, float>();
foreach (NeatSpecies species in activeSpecies)
{
float adjustedFitness = species.CalulateAverageAdjustedFitness();
totalFitness += adjustedFitness;
fitness[species] = adjustedFitness;
}
// Determine how many networks each species has been allocated
Dictionary <NeatSpecies, int> allocation = new Dictionary <NeatSpecies, int>();
int totalNewCount = 0;
foreach (NeatSpecies species in activeSpecies)
{
if (totalFitness <= 0.0f)
{
allocation[species] = 0;
}
else
{
int alloc = (int)((fitness[species] / totalFitness) * newPopulationSize);
allocation[species] = alloc;
totalNewCount += alloc;
}
}
// Handle if new count is too high or low
if (totalNewCount < newPopulationSize)
{
// Randomly allocate the remainder
for (int i = 0; i < newPopulationSize - totalNewCount; ++i)
{
NeatSpecies species = activeSpecies[Random.Range(0, activeSpecies.Count)];
allocation[species]++;
}
}
else if (totalNewCount > newPopulationSize)
{
// Randomly deallocate the remainder
for (int i = 0; i < totalNewCount - newPopulationSize; ++i)
{
NeatSpecies species = activeSpecies[Random.Range(0, activeSpecies.Count)];
allocation[species]--;
}
}
// Generate new popluation
List <NeatNetwork> newPopulation = new List <NeatNetwork>();
foreach (NeatSpecies species in activeSpecies)
{
species.NextGeneration(allocation[species], newPopulation);
}
population = newPopulation.ToArray();
// Assign correct species to the new networks
AssignPopulationToSpecies();
generationCounter++;
Debug.Log("Generation " + generationCounter + " with " + activeSpecies.Count + " species");
return(population);
}