public List<Pair<String, Double>> selectWeightedKeysWithSampling(
ActiveLearningSelectionCriterion criterion, int numSamples, int seed) {
List<Pair<String, Double>> result = new ArrayList<>();
forceTrack("Sampling Keys");
log("" + numSamples + " to collect");
// Get uncertainty
forceTrack("Computing Uncertainties");
Counter<String> weightCounter = uncertainty(criterion);
assert weightCounter.equals(uncertainty(criterion));
endTrack("Computing Uncertainties");
// Compute some statistics
startTrack("Uncertainty Histogram");
// log(new Histogram(weightCounter, 50).toString()); // removed to make the release easier
// (Histogram isn't in CoreNLP)
endTrack("Uncertainty Histogram");
double totalCount = weightCounter.totalCount();
Random random = new Random(seed);
// Flatten counter
List<String> keys = new LinkedList<>();
List<Double> weights = new LinkedList<>();
List<String> zeroUncertaintyKeys = new LinkedList<>();
for (Pair<String, Double> elem :
Counters.toSortedListWithCounts(
weightCounter,
(o1, o2) -> {
int value = o1.compareTo(o2);
if (value == 0) {
return o1.first.compareTo(o2.first);
} else {
return value;
}
})) {
if (elem.second != 0.0
|| weightCounter.totalCount() == 0.0
|| weightCounter.size() <= numSamples) { // ignore 0 probability weights
keys.add(elem.first);
weights.add(elem.second);
} else {
zeroUncertaintyKeys.add(elem.first);
}
}
// Error check
if (Utils.assertionsEnabled()) {
for (Double elem : weights) {
if (!(elem >= 0 && !Double.isInfinite(elem) && !Double.isNaN(elem))) {
throw new IllegalArgumentException("Invalid weight: " + elem);
}
}
}
// Sample
SAMPLE_ITER:
for (int i = 1; i <= numSamples; ++i) { // For each sample
if (i % 1000 == 0) {
// Debug log
log("sampled " + (i / 1000) + "k keys");
// Recompute total count to mitigate floating point errors
totalCount = 0.0;
for (double val : weights) {
totalCount += val;
}
}
if (weights.size() == 0) {
continue;
}
assert totalCount >= 0.0;
assert weights.size() == keys.size();
double target = random.nextDouble() * totalCount;
Iterator<String> keyIter = keys.iterator();
Iterator<Double> weightIter = weights.iterator();
double runningTotal = 0.0;
while (keyIter.hasNext()) { // For each candidate
String key = keyIter.next();
double weight = weightIter.next();
runningTotal += weight;
if (target <= runningTotal) { // Select that sample
result.add(Pair.makePair(key, weight));
keyIter.remove();
weightIter.remove();
totalCount -= weight;
continue SAMPLE_ITER; // continue sampling
}
}
// We should get here only if the keys list is empty
warn(
"No more uncertain samples left to draw from! (target="
+ target
+ " totalCount="
+ totalCount
+ " size="
+ keys.size());
assert keys.size() == 0;
if (zeroUncertaintyKeys.size() > 0) {
result.add(Pair.makePair(zeroUncertaintyKeys.remove(0), 0.0));
} else {
break;
}
}
endTrack("Sampling Keys");
return result;
}
public List<Pair<String, Double>> selectWeightedKeys(ActiveLearningSelectionCriterion criterion) {
Counter<String> weights = uncertainty(criterion);
return Counters.toSortedListWithCounts(weights);
}