private void AssertCount(IReadOnlyList <Entry> elements, int spins = 0)
{
var probabilitySum = elements.Select(e => e.Probability).Sum();
if (spins == 0)
{
var p_min = elements.Min(e => e.Probability);
spins = (int)(1000 / (p_min / probabilitySum));
}
Console.WriteLine($"spins: {spins}");
var roulette = new AliasRoulette <Entry>(random, elements, e => e.Probability);
for (int i = 0; i < spins; i++)
{
roulette.Spin().Count++;
}
foreach (var element in elements)
{
var expectedCount = (element.Probability / probabilitySum) * spins;
var actualCount = (double)element.Count;
actualCount.Should().BeApproximately(expectedCount, expectedCount * 0.1 + 10);
//var expectedProbability = element.Probability / probabilitySum;
//var actualProbability = element.Count / (double)spins;
//actualProbability.Should().BeApproximately(expectedProbability, expectedProbability * 0.05);
}
}
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());
}
}
