public TopicScores getDistanceFromUniform() {
    int[] tokensPerTopic = model.tokensPerTopic;

    TopicScores scores = new TopicScores("uniform_dist", numTopics, numTopWords);
    scores.wordScoresDefined = true;

    int numTypes = alphabet.size();

    for (int topic = 0; topic < numTopics; topic++) {

      double topicScore = 0.0;
      int position = 0;
      TreeSet<IDSorter> sortedWords = topicSortedWords.get(topic);

      for (IDSorter info : sortedWords) {
        int type = info.getID();
        double count = info.getWeight();

        double score =
            (count / tokensPerTopic[topic]) * Math.log((count * numTypes) / tokensPerTopic[topic]);

        if (position < numTopWords) {
          scores.setTopicWordScore(topic, position, score);
        }

        topicScore += score;
        position++;
      }

      scores.setTopicScore(topic, topicScore);
    }

    return scores;
  }
  /** Low-quality topics may have words that are also prominent in other topics. */
  public TopicScores getExclusivity() {

    int[] tokensPerTopic = model.tokensPerTopic;

    TopicScores scores = new TopicScores("exclusivity", numTopics, numTopWords);
    scores.wordScoresDefined = true;

    double sumDefaultProbs = 0.0;
    for (int topic = 0; topic < numTopics; topic++) {
      sumDefaultProbs += model.beta / (model.betaSum + tokensPerTopic[topic]);
    }

    for (int topic = 0; topic < numTopics; topic++) {

      double topicScore = 0.0;
      int position = 0;
      TreeSet<IDSorter> sortedWords = topicSortedWords.get(topic);

      for (IDSorter info : sortedWords) {
        int type = info.getID();
        double count = info.getWeight();

        double sumTypeProbs = sumDefaultProbs;
        int[] topicCounts = model.typeTopicCounts[type];

        int index = 0;
        while (index < topicCounts.length && topicCounts[index] > 0) {

          int otherTopic = topicCounts[index] & model.topicMask;
          int otherCount = topicCounts[index] >> model.topicBits;

          // We've already accounted for the smoothing parameter,
          //  now we need to add the actual count for the non-zero
          //  topics.
          sumTypeProbs += ((double) otherCount) / (model.betaSum + tokensPerTopic[otherTopic]);

          index++;
        }

        double score =
            ((model.beta + count) / (model.betaSum + tokensPerTopic[topic])) / sumTypeProbs;
        scores.setTopicWordScore(topic, position, score);
        topicScore += score;

        position++;
        if (position == numTopWords) {
          break;
        }
      }

      scores.setTopicScore(topic, topicScore / numTopWords);
    }

    return scores;
  }
  public TopicScores getTokenDocumentDiscrepancies() {
    TopicScores scores = new TopicScores("token-doc-diff", numTopics, numTopWords);
    scores.wordScoresDefined = true;

    for (int topic = 0; topic < numTopics; topic++) {
      int[][] matrix = topicCodocumentMatrices[topic];
      TreeSet<IDSorter> sortedWords = topicSortedWords.get(topic);

      double topicScore = 0.0;

      double[] wordDistribution = new double[numTopWords];
      double[] docDistribution = new double[numTopWords];

      double wordSum = 0.0;
      double docSum = 0.0;

      int position = 0;
      Iterator<IDSorter> iterator = sortedWords.iterator();
      while (iterator.hasNext() && position < numTopWords) {
        IDSorter info = iterator.next();

        wordDistribution[position] = info.getWeight();
        docDistribution[position] = matrix[position][position];

        wordSum += wordDistribution[position];
        docSum += docDistribution[position];

        position++;
      }

      for (position = 0; position < numTopWords; position++) {
        double p = wordDistribution[position] / wordSum;
        double q = docDistribution[position] / docSum;
        double meanProb = 0.5 * (p + q);

        double score = 0.0;
        if (p > 0) {
          score += 0.5 * p * Math.log(p / meanProb);
        }
        if (q > 0) {
          score += 0.5 * q * Math.log(q / meanProb);
        }

        scores.setTopicWordScore(topic, position, score);
        topicScore += score;
      }

      scores.setTopicScore(topic, topicScore);
    }

    return scores;
  }
  /** Low-quality topics may be very similar to the global distribution. */
  public TopicScores getDistanceFromCorpus() {

    int[] tokensPerTopic = model.tokensPerTopic;

    TopicScores scores = new TopicScores("corpus_dist", numTopics, numTopWords);
    scores.wordScoresDefined = true;

    for (int topic = 0; topic < numTopics; topic++) {

      double coefficient = (double) numTokens / tokensPerTopic[topic];

      double topicScore = 0.0;
      int position = 0;
      TreeSet<IDSorter> sortedWords = topicSortedWords.get(topic);

      for (IDSorter info : sortedWords) {
        int type = info.getID();
        double count = info.getWeight();

        double score =
            (count / tokensPerTopic[topic]) * Math.log(coefficient * count / wordTypeCounts[type]);

        if (position < numTopWords) {
          // System.out.println(alphabet.lookupObject(type) + ": " + count + " * " + numTokens + " /
          // " + wordTypeCounts[type] + " * " + tokensPerTopic[topic] + " = " + (coefficient * count
          // / wordTypeCounts[type]));
          scores.setTopicWordScore(topic, position, score);
        }

        topicScore += score;

        position++;
      }

      scores.setTopicScore(topic, topicScore);
    }

    return scores;
  }
  public TopicScores getEffectiveNumberOfWords() {
    int[] tokensPerTopic = model.tokensPerTopic;

    TopicScores scores = new TopicScores("eff_num_words", numTopics, numTopWords);

    int numTypes = alphabet.size();

    for (int topic = 0; topic < numTopics; topic++) {

      double sumSquaredProbabilities = 0.0;
      TreeSet<IDSorter> sortedWords = topicSortedWords.get(topic);

      for (IDSorter info : sortedWords) {
        int type = info.getID();
        double probability = info.getWeight() / tokensPerTopic[topic];

        sumSquaredProbabilities += probability * probability;
      }

      scores.setTopicScore(topic, 1.0 / sumSquaredProbabilities);
    }

    return scores;
  }
  public String toXML() {

    int[] tokensPerTopic = model.tokensPerTopic;

    StringBuilder out = new StringBuilder();
    Formatter formatter = new Formatter(out, Locale.US);

    out.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
    out.append("<model>\n");

    for (int topic = 0; topic < numTopics; topic++) {

      int[][] matrix = topicCodocumentMatrices[topic];

      formatter.format("<topic id='%d'", topic);

      for (TopicScores scores : diagnostics) {
        formatter.format(" %s='%.4f'", scores.name, scores.scores[topic]);
      }
      out.append(">\n");

      TreeSet<IDSorter> sortedWords = topicSortedWords.get(topic);

      // How many words should we report? Some topics may have fewer than
      //  the default number of words with non-zero weight.
      int limit = numTopWords;
      if (sortedWords.size() < numTopWords) {
        limit = sortedWords.size();
      }

      double cumulativeProbability = 0.0;

      Iterator<IDSorter> iterator = sortedWords.iterator();
      for (int position = 0; position < limit; position++) {
        IDSorter info = iterator.next();
        double probability = info.getWeight() / tokensPerTopic[topic];
        cumulativeProbability += probability;

        formatter.format(
            "<word rank='%d' count='%.0f' prob='%.5f' cumulative='%.5f' docs='%d'",
            position + 1,
            info.getWeight(),
            probability,
            cumulativeProbability,
            matrix[position][position]);

        for (TopicScores scores : diagnostics) {
          if (scores.wordScoresDefined) {
            formatter.format(" %s='%.4f'", scores.name, scores.topicWordScores[topic][position]);
          }
        }
        formatter.format(
            ">%s</word>\n",
            topicTopWords[topic][position].replaceAll("&", "&amp;").replaceAll("<", "&gt;"));
      }

      out.append("</topic>\n");
    }
    out.append("</model>\n");

    return out.toString();
  }