code: private void computeScore(Sentence sentence, SmartForest<Double> forest) {
          SmartGetWord<Double> sgw = new SmartGetWord<>(forest, sentence.value);
          String name = null;
          while ((name = sgw.getFrontWords()) != null) {
              sentence.updateScore(name, sgw.getParam());
          }
          if (sentence.score == 0) {
              sentence.score = sentence.value.length() * -0.005;
          } else {
              sentence.score /= Math.log(sentence.value.length() + 3);
          }
      }
docs: 计算一个句子的分数
  
  @param sentence
  @param sf