public List<ScoredPhrasePairForSentence> decode(List<String> sentence) {
numSentences++;
long startTime = System.nanoTime();
int length = sentence.size();
System.out.println(String.format("Sentence no: %d Length: %d", numSentences, length));
PhraseTableForSentence phraseTableForSentence = phraseTable.initialize(sentence);
List<HashMap<DecoderState, BackPointerElement>> backPointersList = new ArrayList<>(length + 1);
initializeBackPointersList(backPointersList, length);
List<MinPriorityDecoderQueue<DecoderState>> decoderStateQueues = new ArrayList<>(length + 1);
initializeStateQueues(decoderStateQueues, length);
DecoderState bestState = null;
int counter = 0;
for (int i = 0; i <= length; ++i) {
MinPriorityDecoderQueue<DecoderState> decoderStateQueue = decoderStateQueues.get(i);
while (decoderStateQueue.hasNext()) {
counter = i;
DecoderState state = decoderStateQueue.removeMin();
bestState = state;
List<ScoredPhrasePairForSentence> phrases =
decoderModel.getPossiblePhrases(state, sentence, phraseTableForSentence);
for (ScoredPhrasePairForSentence phrase : phrases) {
DecoderState nextState = decoderModel.getNextState(state, phrase, sentence);
if (nextState != null) {
int nextLength = decoderModel.getDecodedLength(nextState);
MinPriorityDecoderQueue<DecoderState> nextDecoderStateQueue =
decoderStateQueues.get(nextLength);
HashMap<DecoderState, BackPointerElement> nextBackPointers =
backPointersList.get(nextLength);
UpdateStateQueue(nextDecoderStateQueue, nextState, state, phrase, nextBackPointers);
}
}
}
}
List<ScoredPhrasePairForSentence> finalPhrasePairs =
readBackPointers(bestState, backPointersList, counter, length);
long timeDuration = System.nanoTime() - startTime;
double timeDurationInSeconds = (double) timeDuration / 1000000000;
System.out.println(String.format("Time taken: %.2f seconds", timeDurationInSeconds));
return finalPhrasePairs;
}
private List<ScoredPhrasePairForSentence> readBackPointers(
DecoderState state,
List<HashMap<DecoderState, BackPointerElement>> backPointersList,
int startLength,
int sentenceLength) {
DecoderState curState = state;
DecoderState startState = getStartState(sentenceLength);
int curLength = startLength;
List<ScoredPhrasePairForSentence> phrases = new ArrayList<>();
while (!curState.equals(startState)) {
BackPointerElement backPointer = backPointersList.get(curLength).get(curState);
phrases.add(0, backPointer.getPhrase());
curState = backPointer.getState();
curLength = decoderModel.getDecodedLength(curState);
}
return phrases;
}
