/// <summary>
/// Mutate the value randomly, but ensure the mutatet value is bigger
/// </summary>
/// <param name="value"></param>
/// <param name="allel"></param>
/// <returns></returns>
public static double MutatePositive(double value, Allel allel)
{
if (allel.IsOnlyPositive)
{
double offset = (allel.MaxValue - value) * _random.NextDouble();
return(offset + value);
}
throw new NotImplementedException();
}
public static T MutateSlightlyRandom <T>(T candidate, Allel allel, Func <T> childCreator, double maxMutationPitch = DEFAULT_SLIGHT_MUTATION_PITCH) where T : Candidate
{
var mutant = childCreator();
mutant.Prototype(candidate);
var currentValue = mutant.GetAllelValue(allel);
var mutantValue = MutateSlightlyRandom(currentValue, allel, maxMutationPitch);
mutant.SetAllelValue(allel, mutantValue);
return(mutant);
}
public static T MutateRandom <T>(T candidate, Allel allel, Func <T> childCreator) where T : Candidate
{
var mutant = childCreator();
mutant.Prototype(candidate);
var currentValue = mutant.GetAllelValue(allel);
var mutantValue = MutateRandom(currentValue, allel);
mutant.SetAllelValue(allel, mutantValue);
return(mutant);
}
/// <summary>
/// Mutates the given value slightly randomly
/// </summary>
/// <param name="value"></param>
/// <param name="allel"></param>
/// <param name="maxMutationPitch">0.0 - 1.0</param>
/// <returns></returns>
public static double MutateSlightlyRandom(double value, Allel allel, double maxMutationPitch = DEFAULT_SLIGHT_MUTATION_PITCH)
{
double n = _random.NextDouble() * (allel.MaxValue - allel.MinValue);
double newValue = allel.MinValue + n;
// the new value is completly random. the max mutation pitch factor is
// now used to determine, how much influence the new value has
if (maxMutationPitch < FULL_MUTATION_PITCH)
{
//
// a pitch of 1 would mean the old value is completly replaced
// a pitch of 0.5 would mean that they are the avaerage
// a pitch of 0 means that the new value has no effect
//
newValue = value * (1.0d - maxMutationPitch) + newValue * (maxMutationPitch);
}
return(newValue);
}
/// <summary>
/// Mutates the given value randomly
/// </summary>
/// <param name="value"></param>
/// <param name="allel"></param>
/// <returns></returns>
public static double MutateRandom(double value, Allel allel)
{
return(MutateSlightlyRandom(value, allel, FULL_MUTATION_PITCH));
}
/// <summary>
/// Mutate the value randomly, but ensure the mutatet value is bigger
/// </summary>
/// <param name="value"></param>
/// <param name="allel"></param>
/// <returns></returns>
public static double MutateNegative(double value, Allel allel)
{
double offset = (value - allel.MinValue) * _random.NextDouble();
return(value - offset);
}
