RunningAverage precision = new FullRunningAverage();
RunningAverage recall = new FullRunningAverage();
RunningAverage fallOut = new FullRunningAverage();
LongPrimitiveIterator it = dataModel.getUserIDs();
while (it.hasNext()) {
long userID = it.nextLong();
if (random.nextDouble() < evaluationPercentage) {
long start = System.currentTimeMillis();
FastIDSet relevantItemIDs = new FastIDSet(at);
PreferenceArray prefs = dataModel.getPreferencesFromUser(userID);
int size = prefs.length();