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#ifndef _RULE_EXTRACTOR_HELPER_H_
#define _RULE_EXTRACTOR_HELPER_H_
#include <memory>
#include <unordered_map>
#include <vector>
using namespace std;
namespace extractor {
class Alignment;
class DataArray;
/**
* Helper class for extracting SCFG rules.
*/
class RuleExtractorHelper {
public:
RuleExtractorHelper(shared_ptr<DataArray> source_data_array,
shared_ptr<DataArray> target_data_array,
shared_ptr<Alignment> alignment,
int max_rule_span,
int max_rule_symbols,
bool require_aligned_terminal,
bool require_aligned_chunks,
bool require_tight_phrases);
virtual ~RuleExtractorHelper();
// Find the alignment span for each word in the source target sentence pair.
virtual void GetLinksSpans(vector<int>& source_low, vector<int>& source_high,
vector<int>& target_low, vector<int>& target_high,
int sentence_id) const;
// Check if one chunk (all chunks) is aligned at least in one point.
virtual bool CheckAlignedTerminals(const vector<int>& matching,
const vector<int>& chunklen,
const vector<int>& source_low) const;
// Check if the chunks are tight.
virtual bool CheckTightPhrases(const vector<int>& matching,
const vector<int>& chunklen,
const vector<int>& source_low) const;
// Find the target span and the reflected source span for a source phrase
// occurrence.
virtual bool FindFixPoint(
int source_phrase_low, int source_phrase_high,
const vector<int>& source_low, const vector<int>& source_high,
int& target_phrase_low, int& target_phrase_high,
const vector<int>& target_low, const vector<int>& target_high,
int& source_back_low, int& source_back_high, int sentence_id,
int min_source_gap_size, int min_target_gap_size,
int max_new_x, bool allow_low_x, bool allow_high_x,
bool allow_arbitrary_expansion) const;
// Find the gap spans for each nonterminal in the source phrase.
virtual bool GetGaps(
vector<pair<int, int> >& source_gaps, vector<pair<int, int> >& target_gaps,
const vector<int>& matching, const vector<int>& chunklen,
const vector<int>& source_low, const vector<int>& source_high,
const vector<int>& target_low, const vector<int>& target_high,
int source_phrase_low, int source_phrase_high, int source_back_low,
int source_back_high, int& num_symbols, bool& met_constraints) const;
// Get the order of the nonterminals in the target phrase.
virtual vector<int> GetGapOrder(const vector<pair<int, int> >& gaps) const;
// Map each terminal symbol with its position in the source phrase.
virtual unordered_map<int, int> GetSourceIndexes(
const vector<int>& matching, const vector<int>& chunklen,
int starts_with_x) const;
protected:
RuleExtractorHelper();
private:
// Find the projection of a source phrase in the target sentence. May also be
// used to find the projection of a target phrase in the source sentence.
void FindProjection(
int source_phrase_low, int source_phrase_high,
const vector<int>& source_low, const vector<int>& source_high,
int& target_phrase_low, int& target_phrase_high) const;
shared_ptr<DataArray> source_data_array;
shared_ptr<DataArray> target_data_array;
shared_ptr<Alignment> alignment;
int max_rule_span;
int max_rule_symbols;
bool require_aligned_terminal;
bool require_aligned_chunks;
bool require_tight_phrases;
};
} // namespace extractor
#endif
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