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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"

class CentroidCluster: public Cluster
{
public:
  CentroidCluster(int cid, const 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<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:
  FloatFreqVector *centroid;
  ClusterRep *weightedCentroid;
  FloatFreqVector* readCentroid();
  void updateCentroid(FloatFreqVector *v, bool first);
};

#endif

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