@Override
protected void splitProcess(EvolutionState state) {
splits = 0;
List<MetaPopulation> created = new ArrayList<MetaPopulation>();
for (MetaPopulation mp : metaPops) {
if (mp.populations.size() > 1) {
// Find the biggest distance between populations of the same MetaPopulation
int maxI = -1, maxJ = -1;
for (Integer i : mp.populations) {
for (Integer j : mp.populations) {
if (j > i && (maxI == -1 || distanceMatrix[i][j] > distanceMatrix[maxI][maxJ])) {
maxI = i;
maxJ = j;
}
}
}
double threshold =
Math.max(
finalThreshold, finalThreshold + thresholdDeviation - mp.age * thresholdChange);
// Check if it needs to be split
if (distanceMatrix[maxI][maxJ] > threshold) {
// Determine which one will leave the metapopulation
int exitPop = maxJ;
if (mp.populations.size() > 2) {
double maxIdist = 0, maxJdist = 0;
for (Integer k : mp.populations) {
maxIdist += distanceMatrix[k][maxI];
maxJdist += distanceMatrix[k][maxJ];
}
exitPop = maxIdist > maxJdist ? maxI : maxJ;
}
// Do the split -- remove subpop from current metapopulation
System.out.println(
"Spliting "
+ exitPop
+ " from "
+ mp.toString()
+ " D: "
+ distanceMatrix[maxI][maxJ]
+ " T: "
+ threshold);
mp.populations.remove((Object) exitPop);
mp.age = 0;
// Create new metapopulation with subpop and the same individuals as the former metapop
MetaPopulation mpj = new MetaPopulation();
mpj.individuals = state.population.subpops[exitPop].individuals;
mpj.populations.add(exitPop);
created.add(mpj);
splits++;
}
}
}
metaPops.addAll(created);
}
@Override
protected void mergeProcess(EvolutionState state) {
Iterator<MetaPopulation> iter = metaPops.iterator();
while (iter.hasNext()) {
MetaPopulation next = iter.next();
// The population is alone: candidate to merging
if (next.populations.size() == 1) {
// Find the closest metapopulation to merge with
int subpop = next.populations.get(0); // get the single subpopulation
MetaPopulation closest = null;
double distance = Double.POSITIVE_INFINITY;
for (MetaPopulation mp : metaPops) {
if (mp != next) { // can not merge with itself
double d = maxDistance(subpop, mp);
if (d < distance) {
distance = d;
closest = mp;
}
}
}
// One metapop was found, merge with it
if (closest != null) {
double threshold =
Math.min(
finalThreshold,
finalThreshold
- thresholdDeviation
+ Math.min(closest.age, next.age) * thresholdChange);
if (distance < threshold) {
iter.remove(); // delete current metapop
// Integrate in the closest
System.out.println(
"Merging "
+ next.toString()
+ " with "
+ closest.toString()
+ " D: "
+ distance
+ " T: "
+ threshold);
closest.populations.add(subpop);
closest.waitingIndividuals.add(next.individuals);
closest.age = 0;
}
}
}
}
}
