plLearnKLidstone.h

/*==============================================================================
 * Product        : OpenPL 
 * File           : plLearnKLidstone.h
 * Author         : Manuel Yguel
 * Creation       : Mon Nov 10 08:52:09 2003
 *
 *==============================================================================
 *     (c) Copyright 2000, Centre National de la Recherche Scientifique,
 *                              all rights reserved
 *==============================================================================
 *
 *------------------------- Description ----------------------------------------
 *   Learning n dimensionnal Lidstone's distribution with KNOWN variables 
 *   definition sets.
 *   
 *------------------------------------------------------------------------------
 */


#ifndef __plLearnKLidstone_h__
#define __plLearnKLidstone_h__

#include <plLearn.h>
#include <plLearnKHistogram.h>

class plLearnKLidstone : public plLearnKHistogram
{
protected :
  double _alpha; 
public:
 
  plLearnKLidstone():plLearnKHistogram(){}
    
  plLearnKLidstone(const plVariablesConjunction &vars, double alpha= 1.0)
    : plLearnKHistogram( vars ), _alpha( alpha )
  {}
    
  ~plLearnKLidstone(){}
    

  inline void setLidstoneParam( double alpha )
    {
      _alpha = alpha;
    }


  void get_params(plValues &params) const
  {
    double div = _total_weight + _alpha*_freq.size();
    for(unsigned int i = 0; i < _freq.size(); i++){
      params[i] = (_alpha + _freq[i]) / div;
    }
  }
  
  plKernel get_distribution( const void *parameters = NULL ) const
  {
    double alpha = _alpha;
    if( NULL != parameters )
      {
        double *ptr_alpha = (double *)parameters;
        alpha = *ptr_alpha;
      }

    double div = _total_weight + alpha*_freq.size();
    vector <plProbValue> prob( _freq.size() );
    for(unsigned int i = 0; i < _freq.size(); i++){
      prob[i] = (alpha + _freq[i]) / div;
    }
    return ( plProbTable(_left_vars, prob) );
  }
    
  void get_probability(vector <plProbValue> &table)const
  {
    table.resize( _freq.size() );
    double div = _total_weight + _alpha*_freq.size();
    for(unsigned int i = 0; i < _freq.size(); i++) table[i] = (_alpha + _freq[i]) / div;
  }

  void get_probability(plProbValue *table)const
  {
    double div = _total_weight + _alpha*_freq.size();
    for(unsigned int i = 0; i < _freq.size(); i++) table[i] = (_alpha + _freq[i]) / div;
  }

};


#endif

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