Ejemplo n.º 1
0
 /**
  * Builds a Trellis over a sentence, by starting at the state State, and advancing through all
  * legal extensions of each state already in the trellis. You should not have to modify this
  * code (or even read it, really).
  */
 private Trellis<State> buildTrellis(List<String> sentence) {
   Trellis<State> trellis = new Trellis<State>();
   trellis.setStartState(State.getStartState());
   State stopState = State.getStopState(sentence.size() + 2);
   trellis.setStopState(stopState);
   Set<State> states = Collections.singleton(State.getStartState());
   for (int position = 0; position <= sentence.size() + 1; position++) {
     Set<State> nextStates = new HashSet<State>();
     for (State state : states) {
       if (state.equals(stopState)) continue;
       LocalTrigramContext localTrigramContext =
           new LocalTrigramContext(
               sentence, position, state.getPreviousPreviousTag(), state.getPreviousTag());
       Counter<String> tagScores = localTrigramScorer.getLogScoreCounter(localTrigramContext);
       for (String tag : tagScores.keySet()) {
         double score = tagScores.getCount(tag);
         State nextState = state.getNextState(tag);
         trellis.setTransitionCount(state, nextState, score);
         nextStates.add(nextState);
       }
     }
     //        System.out.println("States: "+nextStates);
     states = nextStates;
   }
   return trellis;
 }
Ejemplo n.º 2
0
 public List<S> getBestPath(Trellis<S> trellis) {
   List<S> states = new ArrayList<S>();
   S currentState = trellis.getStartState();
   states.add(currentState);
   while (!currentState.equals(trellis.getEndState())) {
     Counter<S> transitions = trellis.getForwardTransitions(currentState);
     S nextState = transitions.argMax();
     states.add(nextState);
     currentState = nextState;
   }
   return states;
 }