docs: protected static void printFeatureTree(String cs, float[] tempW) {
          String name = "*";
          if (tempW.length == 4) {
              name = "U";
          }
          name += "*" + (cs.charAt(cs.length() - 1) - Config.FEATURE_BEGIN + 1) + ":" + cs.substring(0, cs.length() - 1);
          for (int i = 0; i < tempW.length; i++) {
              if (tempW[i] != 0) {
                  System.out.println(name + "\t" + Config.getTagName(i / 4 - 1) + "\t" + Config.getTagName(i % 4) + "\t"
                                  + tempW[i]);
              }
  
          }
      }