public static Set<? extends Person> weightedCopy(
Collection<? extends Person> persons, Factory factory, int N, Random random) {
if (persons.size() == N) {
return new HashSet<>(persons); // TODO weights are left untouched
} else if (persons.size() > N) {
throw new IllegalArgumentException("Cannot shrink population.");
}
List<Person> templates = new ArrayList<>(persons);
/*
* get max weight
*/
TObjectDoubleHashMap<Person> weights = new TObjectDoubleHashMap<>(persons.size());
double maxW = 0;
for (Person person : persons) {
String wStr = person.getAttribute(CommonKeys.PERSON_WEIGHT);
double w = 0;
if (wStr != null) {
w = Double.parseDouble(wStr);
}
weights.put(person, w);
maxW = Math.max(w, maxW);
}
/*
* adjust weight so that max weight equals probability 1
*/
ProgressLogger.init(N, 2, 10);
Set<Person> clones = new HashSet<>();
while (clones.size() < N) {
Person template = templates.get(random.nextInt(templates.size()));
double w = weights.get(template);
double p = w / maxW;
if (p > random.nextDouble()) {
StringBuilder builder = new StringBuilder();
builder.append(template.getId());
builder.append("clone");
builder.append(clones.size());
Person clone = PersonUtils.deepCopy(template, builder.toString(), factory);
clone.setAttribute(CommonKeys.PERSON_WEIGHT, "1.0");
clones.add(clone);
ProgressLogger.step();
}
}
return clones;
}