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#ifndef moses_FeatureFunction_h
#define moses_FeatureFunction_h
#include <vector>
#include <set>
#include <string>
#include "PhraseBasedFeatureContext.h"
#include "ChartBasedFeatureContext.h"
#include "moses/TypeDef.h"
namespace Moses
{
class Phrase;
class TargetPhrase;
class TranslationOption;
class Hypothesis;
class ChartHypothesis;
class FFState;
class InputType;
class ScoreComponentCollection;
class WordsBitmap;
class WordsRange;
class FactorMask;
/** base class for all feature functions.
*/
class FeatureFunction
{
protected:
/**< all the score producers in this run */
static std::vector<FeatureFunction*> m_producers;
std::string m_description, m_argLine;
std::vector<std::vector<std::string> > m_args;
bool m_tuneable;
size_t m_numScoreComponents;
//In case there's multiple producers with the same description
static std::multiset<std::string> description_counts;
void Initialize(const std::string& description, const std::string &line);
void ParseLine(const std::string& description, const std::string &line);
public:
static const std::vector<FeatureFunction*>& GetFeatureFunctions() {
return m_producers;
}
static FeatureFunction &FindFeatureFunction(const std::string& name);
FeatureFunction(const std::string& description, const std::string &line);
FeatureFunction(const std::string& description, size_t numScoreComponents, const std::string &line);
virtual bool IsStateless() const = 0;
virtual ~FeatureFunction();
//! override to load model files
virtual void Load()
{}
static void ResetDescriptionCounts() {
description_counts.clear();
}
//! returns the number of scores that a subclass produces.
//! For example, a language model conventionally produces 1, a translation table some arbitrary number, etc
size_t GetNumScoreComponents() const {
return m_numScoreComponents;
}
//! returns a string description of this producer
const std::string& GetScoreProducerDescription() const {
return m_description;
}
//! if false, then this feature is not displayed in the n-best list.
// use with care
virtual bool IsTuneable() const {
return m_tuneable;
}
//! Called before search and collecting of translation options
virtual void InitializeForInput(InputType const& source)
{}
// clean up temporary memory, called after processing each sentence
virtual void CleanUpAfterSentenceProcessing(const InputType& source)
{}
const std::string &GetArgLine() const {
return m_argLine;
}
// given a target phrase containing only factors specified in mask
// return true if the feature function can be evaluated
virtual bool IsUseable(const FactorMask &mask) const = 0;
// used by stateless ff. And stateful ff to make initial score estimate during loading of phrase table
virtual void Evaluate(const Phrase &source
, const TargetPhrase &targetPhrase
, ScoreComponentCollection &scoreBreakdown
, ScoreComponentCollection &estimatedFutureScore) const
{}
virtual void Evaluate(const InputType &source
, ScoreComponentCollection &scoreBreakdown) const
{}
virtual bool OverrideParameter(const std::string& key, const std::string& value);
};
}
#endif
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