criterion_multinom_bhattacharyya.hpp

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#ifndef FSTCRITERIONMULTINOMBHATTACHARYYA_H
#define FSTCRITERIONMULTINOMBHATTACHARYYA_H
 /* 
=========================================================================
Copyright and license:
  * FST4 software (with the exception of any bundled or externally linked
    third-party components) is Copyright (C) 2000-present Institute of
    Information Theory and Automation of the Czech Academy of Sciences (UTIA).
  * FST4 is free software: you can redistribute it and/or modify it under
    the terms of the GNU Affero General Public License as published by the
    Free Software Foundation, version 3. The full text of the license is in
    the file LICENSE in the distribution root and at
    https://www.gnu.org/licenses/agpl-3.0.html.
  * FST4 is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
    License for more details.
  * Closed-source use without the AGPL's copyleft obligations requires a
    commercial license from UTIA; in case of interest write to
    utia@utia.cas.cz. LICENSING.md in the distribution root explains both
    options, the contributor license agreement that every contribution
    requires, and the contacts (technical questions and pull requests:
    somol@utia.cas.cz, with "FST" in the subject line).
========================================================================== */
 
#include <memory>
#include <cassert>
#include <iostream>
#include <sstream>
#include <cmath>
#include "error.hpp"
#include "global.hpp"
#include "criterion_multinom.hpp"
#include "model_multinom.hpp"
 
/*============== Template parameter type naming conventions ==============
--------- Numeric types: -------------------------------------------------
DATATYPE - data sample values - usually real numbers (but may be integers
          in text processing etc.)
REALTYPE - must be real numbers - for representing intermediate results of 
          calculations like mean, covariance etc.
IDXTYPE - index values for enumeration of data samples - (nonnegative) integers, 
          extent depends on numbers of samples in data
DIMTYPE - index values for enumeration of features (dimensions), or classes (not 
          class sizes) - (nonnegative) integers, usually lower extent than IDXTYPE, 
          but be aware of expressions like _classes*_features*_features ! 
          in linearized representations of feature matrices for all classes
BINTYPE - feature selection marker type - represents ca. <10 different feature 
          states (selected, deselected, sel./desel. temporarily 1st nested loop, 2nd...)
RETURNTYPE - criterion value: real value, but may be extended in future to support 
          multiple values 
--------- Class types: ---------------------------------------------------
SUBSET       - class of class type Subset 
CLASSIFIER   - class implementing interface defined in abstract class Classifier 
EVALUATOR    - class implementing interface defined in abstract class Sequential_Step 
DISTANCE     - class implementing interface defined in abstract class Distance 
DATAACCESSOR - class implementing interface defined in abstract class Data_Accessor 
INTERVALCONTAINER - class of class type Data_Intervaller 
CONTAINER    - STL container of class type Data_Interval  
========================================================================== */
 
namespace FST {

template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
class Criterion_Multinomial_Bhattacharyya : public Clonable_Impl<Criterion_Multinomial_Bhattacharyya<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR>,Criterion_Multinomial<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR> > {
public:
        typedef Criterion_Multinomial<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR> parent; 
        typedef Clonable_Impl<Criterion_Multinomial_Bhattacharyya,parent> parent_impl; 
        typedef std::shared_ptr<DATAACCESSOR> PDataAccessor;  
        typedef std::shared_ptr<SUBSET> PSubset;              
        Criterion_Multinomial_Bhattacharyya() {_IB_computed=false; notify("Criterion_Multinomial_Bhattacharyya constructor.");}
        virtual ~Criterion_Multinomial_Bhattacharyya() {notify("Criterion_Multinomial_Bhattacharyya destructor.");}

        virtual bool evaluate(RETURNTYPE &result, const PSubset sub) override;
        virtual bool initialize(PDataAccessor da) override; 
 
 
 
        virtual std::ostream& print(std::ostream& os) const override {os << "Criterion_Multinomial_Bhattacharyya()"; return os;}
private:
        friend parent_impl; 
        Criterion_Multinomial_Bhattacharyya(const Criterion_Multinomial_Bhattacharyya& cmb);
private:
        bool _IB_computed; 
};
 
template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
Criterion_Multinomial_Bhattacharyya<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR>::Criterion_Multinomial_Bhattacharyya(const Criterion_Multinomial_Bhattacharyya& cmb) :
        parent_impl(cmb),
        _IB_computed(cmb._IB_computed)
{
        notify("Criterion_Multinomial_Bhattacharyya copy-constructor.");
}
 
 
 
template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
bool Criterion_Multinomial_Bhattacharyya<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR>::evaluate(RETURNTYPE &result, const PSubset sub)
{
        notify("Criterion_Multinomial_Bhattacharyya::evaluate().");
        assert(parent::_model);
        assert(parent::get_n()>0);
        assert(sub);
        if(sub->get_d_raw()==0) return false;
        DIMTYPE _d = sub->get_d_raw();
        DIMTYPE f;
 
        if(_d==1) {// general form of Bhattacharyya unusable, return the individual Bhattacharyya (see the class warning: different scale)
                if(!_IB_computed) {
                        parent::_model->denarrow();
                        parent::_model->compute_theta();
                        parent::_model->compute_IB();
                        _IB_computed=true;      
                }
                { // expects a singleton subset: read its single selected feature index
                        auto r=sub->selected_features(); auto it=r.begin();
                        if(!(it!=r.end())) return false;
                        f=*it;
                }
                assert(f<parent::_model->get_n());
                result = parent::_model->get_IB()[f]; // individual Bhatt - higher values denote better terms
        } else {
                parent::_model->narrow_to(sub);
                parent::_model->compute_theta();
                REALTYPE doc_avg_length = parent::_model->get_doc_avg_length(); // valid after compute_theta() call
                DIMTYPE _classes=parent::_model->get_classes();
                
                REALTYPE *tmpoint1, *tmpoint2;
                RETURNTYPE thetasum;
                RETURNTYPE value=0.0;
                DIMTYPE c1,c2;
                // the DEBUG blocks below trace the per-class-pair accumulation of the Bhattacharyya
                // coefficient; they are compiled in only in DEBUG builds and print nothing otherwise
#ifdef DEBUG
                {
                        std::ostringstream sos; sos << "d="<<_d<<", doc_avg_length="<<doc_avg_length<<std::endl;
                        syncout::print(std::cout,sos);
                }
#endif
                for(c1=0;c1<_classes;c1++) for(c2=c1+1;c2<_classes;c2++) // for class pair c1,c2
                {
                        tmpoint1=&(parent::_model->get_theta()[c1*_d]);
                        tmpoint2=&(parent::_model->get_theta()[c2*_d]);
                        thetasum=0.0;
                        for(f=0;f<_d;f++) 
                        {
                                thetasum+=sqrt(tmpoint1[f]*tmpoint2[f]);
#ifdef DEBUG
                                {
                                        std::ostringstream sos; sos << "classes<"<<c1<<","<<c2<<">: feat "<<f<<".thetasum="<<thetasum<<", tmpoint1[i="<<f<<"]="<< tmpoint1[f]<< ", tmpoint2[i="<<f<<"]="<< tmpoint2[f]<<std::endl;
                                        syncout::print(std::cout,sos);
                                }
#endif
                        }
                        value+= (double)log(thetasum) * parent::_model->get_Pc(c1) * parent::_model->get_Pc(c2); // weighted
                }
                result = (-doc_avg_length)*value;
#ifdef DEBUG
                {
                        std::ostringstream sos; sos << "result="<<result<<std::endl<<std::endl;
                        syncout::print(std::cout,sos);
                }
#endif
        }
        return true;
}
 
template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
bool Criterion_Multinomial_Bhattacharyya<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR>::initialize(PDataAccessor da)
{
        notify("Criterion_Multinomial_Bhattacharyya::initialize().");
        parent::initialize(da);
        _IB_computed=false;
        return true; 
}
 
 
//----------------------------------------------------------------------------

template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
class Criterion_Multinomial_MI : public Clonable_Impl<Criterion_Multinomial_MI<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR>,Criterion_Multinomial<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR> > {
public:
        typedef Criterion_Multinomial<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR> parent; 
        typedef Clonable_Impl<Criterion_Multinomial_MI,parent> parent_impl; 
        typedef std::shared_ptr<DATAACCESSOR> PDataAccessor;  
        typedef std::shared_ptr<SUBSET> PSubset;              
        Criterion_Multinomial_MI() {_MI_computed=false; notify("Criterion_Multinomial_MI constructor.");}
        virtual ~Criterion_Multinomial_MI() {notify("Criterion_Multinomial_MI destructor.");}

        virtual bool evaluate(RETURNTYPE &result, const PSubset sub) override;
        virtual bool initialize(PDataAccessor da) override; 
 
        virtual std::ostream& print(std::ostream& os) const override {os << "Criterion_Multinomial_MI()"; return os;}
private:
        friend parent_impl; 
        Criterion_Multinomial_MI(const Criterion_Multinomial_MI &cmi) : parent_impl(cmi), _MI_computed(cmi._MI_computed) {notify("Criterion_Multinomial_MI copy-constructor.");}
        bool _MI_computed; 
};
 
template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
bool Criterion_Multinomial_MI<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR>::evaluate(RETURNTYPE &result, const PSubset sub)
{
        notify("Criterion_Multinomial_MI::evaluate().");
        assert(parent::_model);
        assert(parent::get_n()>0);
        assert(sub);
        if(sub->get_d_raw()==0) return false;
 
        if(!_MI_computed) {
                parent::_model->denarrow();
                parent::_model->compute_theta();
                parent::_model->compute_MI();
                _MI_computed=true;
        }
        { // sum of individual MI over the selected features;
          // on a singleton (the ranking phase) this equals the individual MI itself
                result=0;
                bool any=false;
                for(DIMTYPE f : sub->selected_features()) {
                        assert(f<parent::_model->get_n());
                        result += parent::_model->get_MI()[f]; // individual MI - higher values denote better terms
                        any=true;
                }
                if(!any) return false;
        }
        return true;
}
 
template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
bool Criterion_Multinomial_MI<RETURNTYPE,DATATYPE,REALTYPE,IDXTYPE,DIMTYPE,SUBSET,DATAACCESSOR>::initialize(PDataAccessor da)
{
        notify("Criterion_Multinomial_MI::initialize().");
        parent::initialize(da);
        _MI_computed=false;
        return true; 
}
 
} // namespace
#endif // FSTCRITERIONMULTINOMBHATTACHARYYA_H ///:~