empiricalexpect.h

Amis - A maximum entropy estimator 一个最大熵模型统计工具

//////////////////////////////////////////////////////////////////////
///
///  Copyright (c) 2000, Yusuke Miyao
///  You may distribute under the terms of the Artistic License.
///
///  <id>$Id: EmpiricalExpect.h,v 1.13 2003/05/16 12:10:44 yusuke Exp $</id>
///  <collection>Maximum Entropy Estimator</collection>
///  <name>EmpiricalExpect.h</name>
///  <overview>Feature expectations given by the training data</overview>
///
//////////////////////////////////////////////////////////////////////

#ifndef Amis_EmpiricalExpect_h_

#define Amis_EmpiricalExpect_h_

#include <amis/configure.h>
#include <amis/Real.h>
#include <amis/ModelBase.h>
#include <amis/EventSpace.h>
#include <amis/ModelFunction.h>
#include <vector>
#include <iostream>

AMIS_NAMESPACE_BEGIN

//////////////////////////////////////////////////////////////////////

class EmpiricalExpectBase : public std::vector< Real > {
public:
  EmpiricalExpectBase() {}
  virtual ~EmpiricalExpectBase() {}

  virtual void debugInfo( std::ostream& ostr ) const {
    for ( std::vector< Real >::const_iterator it = this->begin();
          it != this->end();
          ++it ) {
      ostr << *it << '\n';
    }
  }
  /// Print data
};

inline std::ostream& operator<<( std::ostream& os, const EmpiricalExpectBase& e ) {
  e.debugInfo( os );
  return os;
}

//////////////////////////////////////////////////////////////////////

template < class Model, class EventSpace, bool EnableJointProb = false >
class EmpiricalExpect : public EmpiricalExpectBase {
public:
  typedef typename EventSpace::FeatureType Feature;
  typedef typename Feature::FeatureFreq FeatureFreq;
  typedef typename EventSpace::EventType Event;

private:
  const Model* model;
  const EventSpace* event_space;

public:
  EmpiricalExpect() {
    model = NULL;
    event_space = NULL;
  }
  virtual ~EmpiricalExpect() {}

public:
  void add( FeatureID id, FeatureFreq freq, Real prob ) {
    (*this)[ id ] += static_cast< Real >( prob * freq );
  }

  void initialize( const Model& init_model, const EventSpace& init_event_space ) {
    model = &init_model;
    event_space = &init_event_space;
    assign( model->numFeatures(), 0.0 );
  }
  void setEmpiricalExpectation() {
    AMIS_DEBUG_MESSAGE( 5, "Start setEmpiricalExpectation" );
    for( int i = 0; i < event_space->numEvents(); ++i ) {
      //model->addEventCount( 1 );
      AMIS_DEBUG_MESSAGE( 5, "Event " << i << "\n" );
      const Event& event = (*event_space)[ i ];
      ModelFunction< Model, Event >().setEmpiricalExpectation( *model, event, *this ); // EnableJointProb?
    }
    AMIS_DEBUG_MESSAGE( 5, "END 1st for loop\n" );

    for ( size_type i = 0; i < size(); i++) {
      if ( (*this)[i] == 0.0 ) {
        AMIS_ERROR_MESSAGE( "Empirical count of " << model->featureNameString( i ) << " is 0\n" );
      } else {
        (*this)[i] *= event_space->eventEmpiricalExpectation();
      }
    }
    //cerr << "Emp. Expect.\n";
    AMIS_DEBUG_MESSAGE( 5, "END setEmpiricalExpectation( void )\n" );
    //AMIS_DEBUG_MESSAGE( 5, "Feature Freezing" );
    //model->freezeSomeFeatures( *this, *val_sums,  *vval_sums, *emp_cnt );  
  }
  /// Set empirical expectations of features
};

//////////////////////////////////////////////////////////////////////

AMIS_NAMESPACE_END

#endif // Amis_EmpiricalExpect_h_
// end of EmpiricalExpect.h