private IPhenotype SelectOne(Population population, EAMode mode, IRandomNumberGenerator random)
{
List <IPhenotype> pool = new List <IPhenotype>(_tournamentSize);
for (int i = 0; i < _tournamentSize; i++)
{
pool.Add(population.DrawRandom(random));
}
if (random.NextDouble() < _prob)
{
switch (mode)
{
case EAMode.MaximizeFitness:
return(pool.Max());
case EAMode.MinimizeFitness:
return(pool.Min());
default:
throw new NotImplementedException(mode.ToString());
}
}
else
{
return(pool[random.Next(pool.Count)]);
}
}
public void SelectAdults(Population offspring, Population population, int n, EAMode eamode)
{
population.Clear();
for (int i = 0; i < n; i++)
{
population.Add(offspring[i]);
}
}
public void SelectAdults(Population offspring, Population population, int n, EAMode mode)
{
var roulette = new Roulette <IPhenotype>(_rng, offspring.Size + population.Size);
if (mode == EAMode.MaximizeFitness)
{
roulette.AddAll(offspring, e => e.Fitness);
roulette.AddAll(population, e => e.Fitness);
population.Clear();
for (int i = 0; i < n; i++)
{
population.Add(roulette.SpinAndRemove());
}
}
else if (mode == EAMode.MinimizeFitness)
{
double p_max = Double.MinValue;
double p_min = Double.MaxValue;
foreach (var e in offspring)
{
p_max = Math.Max(e.Fitness, p_max);
p_min = Math.Min(e.Fitness, p_min);
}
foreach (var e in population)
{
p_max = Math.Max(e.Fitness, p_max);
p_min = Math.Min(e.Fitness, p_min);
}
foreach (var e in offspring)
{
roulette.Add(e, (p_max + p_min) - e.Fitness);
}
foreach (var e in population)
{
roulette.Add(e, (p_max + p_min) - e.Fitness);
}
population.Clear();
for (int i = 0; i < n; i++)
{
population.Add(roulette.SpinAndRemove());
}
}
else
{
throw new NotImplementedException(mode.ToString());
}
}
public IEnumerable <(IPhenotype, IPhenotype)> SelectParents(Population population, int n, EAMode mode, IRandomNumberGenerator random)
{
if (!population.IsSorted)
{
throw new ArgumentException("Population is not sorted");
}
for (int i = 0; i < n; i++)
{
yield return(SelectOne(population, random), SelectOne(population, random));
}
}
public IEnumerable <(IPhenotype, IPhenotype)> SelectParents(Population population, int n, EAMode mode, IRandomNumberGenerator random)
{
var roulette = new AliasRoulette <IPhenotype>(random, population, population.GetProbabilitySelector(mode));
for (int i = 0; i < n; i++)
{
yield return(roulette.Spin(), roulette.Spin());
}
}
private const double S = 1; // I think this is configurable, but keep it as is until we are sure.
public IEnumerable <(IPhenotype, IPhenotype)> SelectParents(Population population, int n, EAMode mode, IRandomNumberGenerator random)
{
var std = population.Select(p => p.Fitness).StandardDeviation();
var avg = population.Select(p => p.Fitness).Average();
var roulette = new AliasRoulette <IPhenotype>(random, population, p => S + (p.Fitness - avg) / (2 * std));
for (int i = 0; i < n; i++)
{
yield return(roulette.Spin(), roulette.Spin());
}
}
public IEnumerable <(IPhenotype, IPhenotype)> SelectParents(Population population, int n, EAMode mode, IRandomNumberGenerator random)
{
if (!population.IsSorted)
{
throw new ArgumentException("Population is not sorted");
}
var roulette = new AliasRoulette <IPhenotype>(random, population, (p, i) => GetProb(i, population.Size));
for (int i = 0; i < n; i++)
{
yield return(roulette.Spin(), roulette.Spin());
}
}
