public JSONArray Cluster(String wekaFilePath, int clusterNum) throws Exception {
    File inputFile = new File(wekaFilePath);
    ArffLoader arf = new ArffLoader();
    arf.setFile(inputFile);
    Instances originIns = arf.getDataSet();
    Instances insTest = new Instances(originIns);
    insTest.deleteStringAttributes();
    int totalNum = insTest.numInstances();

    // SimpleKMeans sm = new SimpleKMeans();
    EM em = new EM();
    em.setNumClusters(clusterNum);
    MakeDensityBasedClusterer sm = new MakeDensityBasedClusterer();
    sm.setClusterer(em);
    sm.buildClusterer(insTest);

    System.out.println("totalNum:" + insTest.numInstances());
    System.out.println("============================");
    System.out.println(sm.toString());
    Map<Integer, ArrayList<String>> result = new HashMap<Integer, ArrayList<String>>();
    for (int i = 0; i < clusterNum; i++) {
      result.put(i, new ArrayList<String>());
    }

    for (int i = 0; i < totalNum; i++) {
      Instance ins = originIns.instance(i);
      String word = ins.stringValue(0);
      Instance tempIns = new Instance(ins);
      tempIns.deleteAttributeAt(0);
      int cluster = sm.clusterInstance(tempIns);
      result.get(cluster).add(word);
    }

    // print the result
    ArrayList<String> words = new ArrayList<String>();
    JSONArray keyWords = new JSONArray();
    for (int k : result.keySet()) {
      words = result.get(k);
      PriorityQueue<MyTerm> clusterQueue = new PriorityQueue<MyTerm>(1, MyTermCompare);
      for (int i = 0; i < words.size(); i++) {
        String s = words.get(i);
        assert linkMap.containsKey(s);
        int freq = linkMap.get(s).totalFreq;
        clusterQueue.add(linkMap.get(s));
        words.set(i, "(" + s + ":" + freq + ")");
      }

      JSONArray clusterArray = new JSONArray();
      int num = clusterQueue.size() / 10 + 1; // 5%
      int totalFreq = 0;
      int totalLength = 0;
      for (int i = 0; i < num && !clusterQueue.isEmpty(); ) {
        JSONObject mem = new JSONObject();
        MyTerm myTerm = clusterQueue.poll();
        String word = myTerm.originTrem.text();
        if (word.length() == 1) {
          continue;
        }
        mem.put("text", word);
        mem.put("freq", myTerm.totalFreq);
        clusterArray.put(mem);
        i++;
        totalFreq += myTerm.totalFreq;
        totalLength += word.length();
      }

      double averFreq = totalFreq * 1.0 / num;
      double averLength = totalLength * 1.0 / num;
      int count = 0;
      while (!clusterQueue.isEmpty() && count < num) {
        MyTerm myTerm = clusterQueue.poll();
        String word = myTerm.originTrem.text();
        int freq = myTerm.totalFreq;
        int times = (int) (word.length() / averFreq) + 1;
        if (freq > averFreq / times) {
          JSONObject mem = new JSONObject();
          mem.put("text", word);
          mem.put("freq", freq);
          mem.put("extra", true);
          clusterArray.put(mem);
        }
      }

      keyWords.put(clusterArray);
      System.out.println(
          "cluster" + k + ":" + words.size() + ":\t" + (int) (words.size() * 1.0 / totalNum * 100));
      if (result.get(k).size() < 100) {
        System.out.println(result.get(k));
      }
    }
    // System.out.println("errorNum:"+errorNum);
    return keyWords;
  }