CentroidCluster.hpp

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/*==========================================================================
 * Copyright (c) 2002 University of Massachusetts.  All Rights Reserved.
 *
 * Use of the Lemur Toolkit for Language Modeling and Information Retrieval
 * is subject to the terms of the software license set forth in the LICENSE
 * file included with this software, and also available at
 * http://www.lemurproject.org/license.html
 *
 *==========================================================================
 */

// David Fisher
// init: 11/20/2002
// Centroid clustering algorithms.
#ifndef _CENTROIDCLUSTER_HPP
#define _CENTROIDCLUSTER_HPP
#include "Cluster.hpp"
namespace lemur
{
  namespace cluster 
  {    
    class CentroidCluster: public Cluster
    {
    public:
      CentroidCluster(int cid, const lemur::api::Index &ind, 
                      const SimilarityMethod &sim);
      virtual ~CentroidCluster() {
        delete(centroid);
        delete(weightedCentroid);
      };
      virtual double score(const ClusterRep *rep) const;
      virtual void add(const ClusterElt &elt);
      virtual void add(const vector<lemur::api::DOCID_T> docids);
      virtual void remove(const ClusterElt &elt);
      virtual bool read(ifstream &in);

      virtual ClusterRep *getClusterRep() const;

      virtual double sum2() const {return weightedCentroid->sum2(); }
  
    private:
      lemur::utility::FloatFreqVector *centroid;
      ClusterRep *weightedCentroid;
      lemur::utility::FloatFreqVector* readCentroid();
      void updateCentroid(lemur::utility::FloatFreqVector *v, bool first);
    };
  }
}

#endif

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