/// <summary>
/// Mutates each element of a <see cref="ListEntityBase"/> if it meets a certain
/// probability.
/// </summary>
/// <param name="entity"><see cref="ListEntityBase"/> to be mutated.</param>
/// <returns>True if a mutation occurred; otherwise, false.</returns>
/// <exception cref="ArgumentNullException"><paramref name="entity"/> is null.</exception>
protected override bool GenerateMutation(GeneticEntity entity)
{
if (entity is null)
{
throw new ArgumentNullException(nameof(entity));
}
ListEntityBase listEntity = (ListEntityBase)entity;
if (RandomNumberService.Instance.GetDouble() <= this.MutationRate)
{
int firstPosition = RandomNumberService.Instance.GetRandomValue(listEntity.Length - 1);
int secondPosition;
do
{
secondPosition = RandomNumberService.Instance.GetRandomValue(listEntity.Length - 1);
} while (secondPosition == firstPosition);
object?firstValue = listEntity.GetValue(firstPosition);
listEntity.SetValue(firstPosition, listEntity.GetValue(secondPosition));
listEntity.SetValue(secondPosition, firstValue);
return(true);
}
return(false);
}
/// <summary>
/// Mutates each bit of a <see cref="ListEntityBase"/> if it meets a certain
/// probability.
/// </summary>
/// <param name="entity"><see cref="ListEntityBase"/> to be mutated.</param>
/// <returns>True if a mutation occurred; otherwise, false.</returns>
/// <exception cref="ArgumentNullException"><paramref name="entity"/> is null.</exception>
protected override bool GenerateMutation(GeneticEntity entity)
{
if (entity is null)
{
throw new ArgumentNullException(nameof(entity));
}
ListEntityBase listEntity = (ListEntityBase)entity;
if (RandomNumberService.Instance.GetDouble() <= this.MutationRate)
{
int firstPosition = RandomNumberService.Instance.GetRandomValue(listEntity.Length);
int secondPosition;
do
{
secondPosition = RandomNumberService.Instance.GetRandomValue(listEntity.Length);
} while (secondPosition == firstPosition);
if (firstPosition < secondPosition)
{
object?currentMovingValue = listEntity.GetValue(firstPosition);
for (int i = firstPosition + 1; i <= secondPosition; i++)
{
object?savedValue = listEntity.GetValue(i);
listEntity.SetValue(i, currentMovingValue);
currentMovingValue = savedValue;
}
listEntity.SetValue(firstPosition, currentMovingValue);
}
else
{
object?currentMovingValue = listEntity.GetValue(firstPosition);
for (int i = firstPosition - 1; i >= secondPosition; i--)
{
object?savedValue = listEntity.GetValue(i);
listEntity.SetValue(i, currentMovingValue);
currentMovingValue = savedValue;
}
listEntity.SetValue(firstPosition, currentMovingValue);
}
return(true);
}
return(false);
}
/// <summary>
/// Returns the list of bits contained in <paramref name="entity"/>.
/// </summary>
/// <param name="entity"><see cref="ListEntityBase"/> whose bits are to be returned.</param>
/// <returns>List of bits contained in <paramref name="entity"/>.</returns>
private static List <object?> GetEntityElements(ListEntityBase entity)
{
List <object?> elements = new List <object?>();
for (int i = 0; i < entity.Length; i++)
{
elements.Add(entity.GetValue(i));
}
return(elements);
}
/// <summary>
/// Returns whether the entity contains the specified value.
/// </summary>
/// <param name="entity">Entity to use.</param>
/// <param name="value">Value to search for.</param>
/// <param name="maxIndex">The max index to iterate to when searching for the value.</param>
/// <returns>True if the value was found; otherwise, false.</returns>
private static bool ContainsValue(ListEntityBase entity, object?value, int maxIndex)
{
for (int i = 0; i <= maxIndex; i++)
{
if (Object.Equals(entity.GetValue(i), value))
{
return(true);
}
}
return(false);
}
private object?GetEntityValue(int index, ListEntityBase entity, ListEntityBase sourceEntity, ListEntityBase originalEntity, ListEntityBase originalOtherEntity)
{
object?entitySourceVal = sourceEntity.GetValue(index);
if (((ListEntityBase?)this.Algorithm?.GeneticEntitySeed)?.RequiresUniqueElementValues == true)
{
while (ContainsValue(entity, entitySourceVal, index - 1))
{
int duplicateValueIndex = originalOtherEntity.IndexOf(entitySourceVal);
entitySourceVal = originalEntity.GetValue(duplicateValueIndex);
}
}
return(entitySourceVal);
}
/// <summary>
/// When overriden in a derived class, generates a crossover based on the parent entities.
/// </summary>
/// <param name="parents">The <see cref="GeneticEntity"/> objects to be operated upon.</param>
/// <returns>
/// Collection of the <see cref="GeneticEntity"/> objects resulting from the crossover.
/// </returns>
protected override IEnumerable <GeneticEntity> GenerateCrossover(IList <GeneticEntity> parents)
{
if (parents == null)
{
throw new ArgumentNullException(nameof(parents));
}
ListEntityBase listEntity1 = (ListEntityBase)parents[0];
ListEntityBase listEntity2 = (ListEntityBase)parents[1];
int entity1Length = listEntity1.Length;
int entity2Length = listEntity2.Length;
int crossoverLocus = RandomNumberService.Instance.GetRandomValue(Math.Min(entity1Length, entity2Length));
IList <GeneticEntity> crossoverOffspring = new List <GeneticEntity>();
int maxLength = Math.Max(entity1Length, entity2Length);
// Normalize the lists into a common length
if (entity1Length != entity2Length)
{
listEntity1.Length = maxLength;
listEntity2.Length = maxLength;
}
// swap the elements of the lists starting at the crossover locus
for (int i = crossoverLocus; i < maxLength; i++)
{
object?tempGeneValue = listEntity1.GetValue(i);
listEntity1.SetValue(i, listEntity2.GetValue(i));
listEntity2.SetValue(i, tempGeneValue);
}
// Set the length based on their swapped length
listEntity1.Length = entity2Length;
listEntity2.Length = entity1Length;
crossoverOffspring.Add(listEntity1);
crossoverOffspring.Add(listEntity2);
return(crossoverOffspring);
}
