/**
* Calculate the {@linkplain Vector} that is the resultant of several difference vectors.
*
* @param participants The {@linkplain Entity} list to create the difference vectors from. It is
* very important to note that the {@linkplain Entity} objects within this list should not
* contain duplicates. If duplicates are contained, this will severely reduce the diversity of
* the population as not all entities will be considered.
* @return A {@linkplain Vector} representing the resultant of all calculated difference vectors.
*/
protected Vector determineDistanceVector(List<Entity> participants) {
RandomProvider random = new MersenneTwister();
Vector distanceVector = Vector.fill(0.0, participants.get(0).getCandidateSolution().size());
Iterator<Entity> iterator;
int number = Double.valueOf(this.numberOfDifferenceVectors.getParameter()).intValue();
List<Entity> currentParticipants;
Vector first, second;
double difference;
for (int d = 0; d < distanceVector.size(); d++) {
// get random participants for this dimension
currentParticipants =
(List<Entity>)
Selection.copyOf(participants)
.orderBy(new RandomArrangement(random))
.select(Samples.first(number));
iterator = currentParticipants.iterator();
while (iterator.hasNext()) {
first = (Vector) iterator.next().getCandidateSolution();
second = (Vector) iterator.next().getCandidateSolution();
difference = first.doubleValueOf(d) - second.doubleValueOf(d);
distanceVector.setReal(d, distanceVector.get(d).doubleValue() + difference);
}
}
return distanceVector;
}
/**
* Calculate the {@linkplain Vector} that is the resultant of several difference vectors.
*
* @param participants The {@linkplain Entity} list to create the difference vectors from. It is
* very important to note that the {@linkplain Entity} objects within this list should not
* contain duplicates. If duplicates are contained, this will severely reduce the diversity of
* the population as not all entities will be considered.
* @return A {@linkplain Vector} representing the resultant of all calculated difference vectors.
*/
protected <T extends Entity> Vector determineDistanceVector(List<T> participants) {
Vector distanceVector = Vector.fill(0.0, participants.get(0).getCandidateSolution().size());
Iterator<T> iterator = participants.iterator();
while (iterator.hasNext()) {
Vector first = (Vector) iterator.next().getCandidateSolution();
Vector second = (Vector) iterator.next().getCandidateSolution();
Vector difference = first.subtract(second);
distanceVector = distanceVector.plus(difference);
}
return distanceVector;
}
