Examples of MRFBuilder

    }


    try {
      Node modelNode = d.getElementsByTagName("model").item(0);


      MRFBuilder builder = MRFBuilder.get(mEnv, modelNode.cloneNode(true));


      
      // Set the default number of hits to 2000 because that's what we had in our
      // official TREC 2009 web track runs; otherwise, IF merging approach
      // will give slightly different results, so we won't be able to


    // Find the best concepts for each of the expansion models.
    for (int modelNum = 0; modelNum < builders.size(); modelNum++) {
      // Get information about this expansion model.
      int curGramSize = gramSizes.get(modelNum);
      MRFBuilder curBuilder = builders.get(modelNum);
      int curFbDocs = fbDocList.get(modelNum);
      int curFbTerms = fbTermList.get(modelNum);


      // Gather Accumulators we're actually going to use for feedback purposes.
      Accumulator[] fbResults = new Accumulator[Math.min(results.length, curFbDocs)];
      for (int i = 0; i < Math.min(results.length, curFbDocs); i++) {
        fbResults[i] = results[i];
      }


      // Sort the Accumulators by docid.
      Arrays.sort(fbResults, new Accumulator.DocnoComparator());


      // Get docnos that correspond to the accumulators.
      int[] docSet = Accumulator.accumulatorsToDocnos(fbResults);


      // Get document vectors for results.
      IntDocVector[] docVecs = env.documentVectors(docSet);


      // Extract vocabulary from results.
      VocabFrequencyPair[] vocab = null;
      try {
        vocab = getVocabulary(docVecs, curGramSize);
      } catch (IOException e) {
        throw new RuntimeException("Error: Unable to fetch the vocabulary!");
      }


      // Priority queue for the concepts associated with this builder.
      PriorityQueue<Accumulator> sortedConcepts = new PriorityQueue<Accumulator>();


      // Score each concept.
      for (int conceptID = 0; conceptID < vocab.length; conceptID++) {
        if (maxCandidates > 0 && conceptID >= maxCandidates) {
          break;
        }


        // The current concept.
        String concept = vocab[conceptID].getKey();


        String[] concepts = concept.split(" ");
        MarkovRandomField conceptMRF = curBuilder.buildMRF(concepts);


        MRFDocumentRanker ranker = new MRFDocumentRanker(conceptMRF, docSet, docSet.length);
        Accumulator[] conceptResults = ranker.rank();
        Arrays.sort(conceptResults, new Accumulator.DocnoComparator());


        float score = 0.0f;
        for (int i = 0; i < conceptResults.length; i++) {
          if (fbResults[i].docno != conceptResults[i].docno) {
            throw new RetrievalException("Error: Mismatch occured in getExpandedMRF!");
          }
          score += Math.exp(fbResults[i].score + conceptResults[i].score);
        }


        int size = sortedConcepts.size();
        if (size < curFbTerms || sortedConcepts.peek().score < score) {
          if (size == curFbTerms) {
            sortedConcepts.poll(); // Remove worst concept.
          }
          sortedConcepts.add(new Accumulator(conceptID, score));
        }
      }


      // Compute the weights of the expanded terms.
      int numTerms = Math.min(curFbTerms, sortedConcepts.size());
      float totalWt = 0.0f;
      Accumulator[] bestConcepts = new Accumulator[numTerms];
      for (int i = 0; i < numTerms; i++) {
        Accumulator a = sortedConcepts.poll();
        bestConcepts[i] = a;
        totalWt += a.score;
      }


      // Add cliques corresponding to best expansion concepts.
      for (int i = 0; i < numTerms; i++) {
        Accumulator a = bestConcepts[i];


        // Construct the MRF corresponding to this concept.
        String[] concepts = vocab[a.docno].getKey().split(" ");
        MarkovRandomField conceptMRF = curBuilder.buildMRF(concepts);


        // Normalized score.
        float normalizedScore = a.score / totalWt;


        // Add cliques.

      }
      RetrievalEnvironment.topK = kVal;


      // Initialize retrieval environment variables.
      CascadeQueryRunner runner = null;
      MRFBuilder builder = null;
      MRFExpander expander = null;


      try {
        // Get the MRF builder.
        builder = MRFBuilder.get(env, modelNode.cloneNode(true));

Examples of MRFBuilder

Examples of ivory.smrf.model.builder.MRFBuilder

Examples of ivory.smrf.model.builder.MRFBuilder

Examples of ivory.smrf.model.builder.MRFBuilder