criterion_wrapper.hpp

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#ifndef FSTCRITERIONWRAPPER_H
#define FSTCRITERIONWRAPPER_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 <cmath>
#include "error.hpp"
#include "global.hpp"
#include "criterion.hpp"
#include "wrapper_metrics.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, class SUBSET, class CLASSIFIER, class DATAACCESSOR>
class Criterion_Wrapper : public Clonable_Impl<Criterion_Wrapper<RETURNTYPE,SUBSET,CLASSIFIER,DATAACCESSOR>,Criterion<RETURNTYPE,SUBSET> > { // adapter class
public:
        typedef Clonable_Impl<Criterion_Wrapper,Criterion<RETURNTYPE,SUBSET> > parent_impl; 
        typedef std::shared_ptr<CLASSIFIER> PClassifier;      
        typedef std::shared_ptr<DATAACCESSOR> PDataAccessor;  
        typedef std::shared_ptr<SUBSET> PSubset;              
        Criterion_Wrapper() {notify("Criterion_Wrapper constructor.");}
        virtual ~Criterion_Wrapper() {notify("Criterion_Wrapper destructor.");}
        
        virtual void initialize(const PClassifier classifier, const PDataAccessor da);

        virtual bool evaluate(RETURNTYPE &result, const PSubset sub) override;

        void set_metric(const Metric_Spec<RETURNTYPE> &spec) {_metric_spec=spec;}
        const Metric_Spec<RETURNTYPE>& get_metric() const {return _metric_spec;} 
 
 
        virtual std::ostream& print(std::ostream& os) const override {os << "Criterion_Wrapper()"; if(_classifier) os << " with " << *_classifier; return os;}
protected:
        friend parent_impl; 
        Criterion_Wrapper(const Criterion_Wrapper& cw);
 
        std::shared_ptr<CLASSIFIER> _classifier;    
        std::shared_ptr<DATAACCESSOR> _da;          
        Metric_Spec<RETURNTYPE> _metric_spec;       
};
 
template<class RETURNTYPE, class SUBSET, class CLASSIFIER, class DATAACCESSOR>
Criterion_Wrapper<RETURNTYPE,SUBSET,CLASSIFIER,DATAACCESSOR>::Criterion_Wrapper(const Criterion_Wrapper& cw)
{
        notify("Criterion_Wrapper copy-constructor.");
        _classifier=clone_unique(*cw._classifier);
        _da=sharing_clone_unique(*cw._da);
        _metric_spec=cw._metric_spec;
}
 
 
 
template<class RETURNTYPE, class SUBSET, class CLASSIFIER, class DATAACCESSOR>
void Criterion_Wrapper<RETURNTYPE,SUBSET,CLASSIFIER,DATAACCESSOR>::initialize(const PClassifier classifier, const PDataAccessor da) // passing by std::shared_ptr to enable keeping the reference throughout *this life cycle
{
        assert(da);
        assert(classifier);
        _da=da;
        _classifier=classifier;
}
 
template<class RETURNTYPE, class SUBSET, class CLASSIFIER, class DATAACCESSOR>
bool Criterion_Wrapper<RETURNTYPE,SUBSET,CLASSIFIER,DATAACCESSOR>::evaluate(RETURNTYPE &result, const PSubset sub)
{
        assert(_da);
        assert(_classifier);
        RETURNTYPE val;
        result=0.0;
        RETURNTYPE cnt=0.0;
        if(!_metric_spec.is_default()) {
                // non-default metric: per-split metric, then mean over splits (macro over folds,
                // same shape as the accuracy path below). Splits on which the metric is undefined
                // (e.g. AUC with a single-class fold) are skipped; all-splits-undefined = failure.
                for(bool b=_da->getFirstSplit();b==true;b=_da->getNextSplit()) {
                        if(!_classifier->train(_da,sub)) return false;
                        if(_classifier->test_metric(val,_da,_metric_spec)) {
                                result+=val;
                                cnt+=1.0;
                        }
                }
                if(cnt==0.0) return false;
                result/=(RETURNTYPE)cnt;
                return true;
        }
        for(bool b=_da->getFirstSplit();b==true;b=_da->getNextSplit()) {
                if(!_classifier->train(_da,sub)) return false;
                if(!_classifier->test(val,_da)) return false;
                result+=val;
                cnt+=1.0;
        }
        if(cnt==0.0) return false; // no split produced (an unprepared or exhausted splitter)
        result/=(RETURNTYPE)cnt;
        return true;
}
 
} // namespace
#endif // FSTCRITERIONWRAPPER_H ///:~