if (stopWord.equals(event.modHeadWord())) return leftModNTProb;
  public double logProbLeft(int id, TrainerEvent event) {    Model leftModNTModel = modelCollection.leftModNonterminalModel();    Model leftModWordModel = modelCollection.leftModWordModel();    double leftModNTProb = leftModNTModel.estimateLogProb(id, event);    if (leftModNTProb == Constants.logOfZero)      return Constants.logOfZero;    double leftWordProb = leftModWordModel.estimateLogProb(id, event);    if (leftWordProb == Constants.logOfZero)      return Constants.logOfZero;    return leftModNTProb + leftWordProb;  }