LMert.h

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//Copyright (c) 2012, University of Cambridge
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#ifndef LMERT_H_
#define LMERT_H_

#include <vector>

#include <fst/fstlib.h>

#include "MertCommon.h"
#include "function-weight.h"

bool GradientSortPredicate (const MertLine& line1, const MertLine& line2);

class MertEnvelope {
 public:
  void SortLines(); // sort envelope lines by slope
  void SweepLine(); // compute upper envelope of lines in array
  std::string ToString (
    bool); // returns lines that constitute the envelope as a string
  std::vector<MertLine> lines; // lines that define the envelope / convex hull
};

class MertLattice {
 public:
  MertLattice (TupleArcFst *, const PARAMS&, const PARAMS&);
  void InitializeEnvelopes();
  void InitializeStartState();
  void PropagateEnvelope (const TupleArcFst::StateId&,
                          const TupleArcFst::StateId&,
                          const TupleW&, const Wid& w);
  void ComputeStateEnvelopes();
  void ComputeFinalEnvelope();
  MertEnvelope ComputeLatticeEnvelope();
 private:
  TupleArcFst* fst;
  std::vector<MertEnvelope> envelopes;
  PARAMS lambda;
  PARAMS direction;
};

class LMertAlgorithm {
 public:
  typedef std::vector<MertLine> Lines;

  static Lines const ComputeLatticeEnvelope (TupleArcFst*, const PARAMS&,
      const PARAMS&);
};

#endif /* LMERT_H_ */