candidate_evaluator_sequential.hpp

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#ifndef FSTCANDIDATEEVALUATORSEQUENTIAL_H
#define FSTCANDIDATEEVALUATORSEQUENTIAL_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 "error.hpp"
#include "global.hpp"
#include "candidate_evaluator.hpp"
 
namespace FST {

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION>
class Candidate_Evaluator_Sequential : public Candidate_Evaluator<RETURNTYPE,DIMTYPE,SUBSET,CRITERION> {
public:
        typedef Candidate_Evaluator<RETURNTYPE,DIMTYPE,SUBSET,CRITERION> parent; 
        typedef typename parent::PCriterion PCriterion;             
        typedef typename parent::PSubset PSubset;                   
        typedef typename parent::PResultTracker PResultTracker;     
        typedef typename parent::Generator Generator;                
        typedef typename parent::ResultCallback ResultCallback;      
        typedef typename parent::BestCallback BestCallback;          
        typedef typename parent::BetterPredicate BetterPredicate;    
 
        Candidate_Evaluator_Sequential() : _best_available(false), _bestval(RETURNTYPE()), _bestfeature(0), _evaluated(0), _failed(false) {notify("Candidate_Evaluator_Sequential constructor.");}
        virtual ~Candidate_Evaluator_Sequential() {notify("Candidate_Evaluator_Sequential destructor.");}
 
        virtual unsigned int get_max_threads() const override {return 1;}
        virtual bool is_threaded() const override {return false;}
 
        virtual void initialize(const PCriterion &crit, const DIMTYPE max_candidates, ResultCallback on_result=ResultCallback()) override
        {
                assert(crit);
                _crit=crit;
                _on_result=on_result;
                _best_available=false;
                _evaluated=0;
                _failed=false;
        }
 
        virtual bool add_candidate(const PSubset &sub, const DIMTYPE feature=0) override
        {
                assert(_crit);
                assert(sub);
                RETURNTYPE val;
                if(!_crit->evaluate(val,sub)) {_failed=true; return false;}
                ++_evaluated;
                if(_on_result) _on_result(val,sub,feature);
                if(!_best_available || val>_bestval) {
                        if(!_bestsub || _bestsub->get_n()!=sub->get_n()) _bestsub.reset(new SUBSET(sub->get_n()));
                        _bestsub->stateless_copy(*sub);
                        _bestval=val;
                        _bestfeature=feature;
                        _best_available=true;
                }
                return true;
        }

        virtual bool collect() override {return _evaluated>0 && !_failed;}
 
        virtual bool getBestResult(RETURNTYPE &result, PSubset &sub, DIMTYPE &feature) override
        {
                if(!_best_available || _failed) return false; // a failed batch hands out nothing, as in the threaded engine
                result=_bestval;
                sub=_bestsub;
                feature=_bestfeature;
                return true;
        }
 
        virtual bool evaluate_stream(Generator generator, const PCriterion &crit, const PResultTracker tracker, BetterPredicate better, BestCallback on_best, RETURNTYPE &result, const PSubset bestsub) override
        {
                assert(generator);
                assert(crit);
                assert(better);
                assert(bestsub);
                assert(bestsub->get_n()>0);
                PSubset tmp_sub(new SUBSET(bestsub->get_n()));
                RETURNTYPE val;
                bool best_available=false;
                unsigned long long ordinal=0; // 64-bit to match BestCallback (see the LLP64 note there)
                while(generator(*tmp_sub)) {
                        if(!crit->evaluate(val,tmp_sub)) return false;
                        if(tracker) tracker->add(val,tmp_sub);
                        if(!best_available || better(val,tmp_sub,result,bestsub)) {
                                result=val;
                                bestsub->stateless_copy(*tmp_sub);
                                best_available=true;
                                if(on_best) on_best(-1,ordinal,val,tmp_sub);
                        }
                        ++ordinal;
                }
                return best_available;
        }
 
        virtual std::ostream& print(std::ostream& os) const override {os << "Candidate_Evaluator_Sequential()"; return os;}
 
protected:
        PCriterion _crit;              
        ResultCallback _on_result;     
        PSubset _bestsub;               
        bool _best_available;          
        RETURNTYPE _bestval;           
        DIMTYPE _bestfeature;          
        DIMTYPE _evaluated;            
        bool _failed;                  
};
 
} // namespace
#endif // FSTCANDIDATEEVALUATORSEQUENTIAL_H ///:~