diff options
author | Chris Dyer <redpony@gmail.com> | 2009-12-03 16:49:30 -0500 |
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committer | Chris Dyer <redpony@gmail.com> | 2009-12-03 16:49:30 -0500 |
commit | 9fae7b75c64f4dfb6e45ff8f2ec61b597f37d225 (patch) | |
tree | 61a187c4fa6db8527f90f3060d18357f7b60b44a /vest/viterbi_envelope.h | |
parent | 671c21451542e2dd20e45b4033d44d8e8735f87b (diff) |
fix build in new layout
Diffstat (limited to 'vest/viterbi_envelope.h')
-rw-r--r-- | vest/viterbi_envelope.h | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/vest/viterbi_envelope.h b/vest/viterbi_envelope.h new file mode 100644 index 00000000..39d2b537 --- /dev/null +++ b/vest/viterbi_envelope.h @@ -0,0 +1,79 @@ +#ifndef _VITERBI_ENVELOPE_H_ +#define _VITERBI_ENVELOPE_H_ + +#include <vector> +#include <iostream> +#include <boost/shared_ptr.hpp> + +#include "hg.h" +#include "sparse_vector.h" + +static const double kMinusInfinity = -std::numeric_limits<double>::infinity(); +static const double kPlusInfinity = std::numeric_limits<double>::infinity(); + +struct Segment { + Segment() : x(), m(), b() {} + Segment(double _m, double _b) : + x(kMinusInfinity), m(_m), b(_b) {} + Segment(double _x, double _m, double _b, const boost::shared_ptr<Segment>& p1_, const boost::shared_ptr<Segment>& p2_) : + x(_x), m(_m), b(_b), p1(p1_), p2(p2_) {} + Segment(double _m, double _b, TRulePtr _rule) : + x(kMinusInfinity), m(_m), b(_b), rule(_rule) {} + + double x; // x intersection with previous segment in env, or -inf if none + double m; // this line's slope + double b; // intercept with y-axis + + // we keep a pointer to the "parents" of this segment so we can reconstruct + // the Viterbi translation corresponding to this segment + boost::shared_ptr<Segment> p1; + boost::shared_ptr<Segment> p2; + + // only Segments created from an edge using the ViterbiEnvelopeWeightFunction + // have rules + TRulePtr rule; + + // recursively recover the Viterbi translation that will result from setting + // the weights to origin + axis * x, where x is any value from this->x up + // until the next largest x in the containing ViterbiEnvelope + void ConstructTranslation(std::vector<WordID>* trans) const; +}; + +// this is the semiring value type, +// it defines constructors for 0, 1, and the operations + and * +struct ViterbiEnvelope { + // create semiring zero + ViterbiEnvelope() : is_sorted(true) {} // zero + // for debugging: + ViterbiEnvelope(const std::vector<boost::shared_ptr<Segment> >& s) : segs(s) { Sort(); } + // create semiring 1 or 0 + explicit ViterbiEnvelope(int i); + ViterbiEnvelope(int n, Segment* seg) : is_sorted(true), segs(n, boost::shared_ptr<Segment>(seg)) {} + const ViterbiEnvelope& operator+=(const ViterbiEnvelope& other); + const ViterbiEnvelope& operator*=(const ViterbiEnvelope& other); + bool IsMultiplicativeIdentity() const { + return size() == 1 && (segs[0]->b == 0.0 && segs[0]->m == 0.0) && (!segs[0]->rule); } + const std::vector<boost::shared_ptr<Segment> >& GetSortedSegs() const { + if (!is_sorted) Sort(); + return segs; + } + size_t size() const { return segs.size(); } + + private: + bool IsEdgeEnvelope() const { + return segs.size() == 1 && segs[0]->rule; } + void Sort() const; + mutable bool is_sorted; + mutable std::vector<boost::shared_ptr<Segment> > segs; +}; +std::ostream& operator<<(std::ostream& os, const ViterbiEnvelope& env); + +struct ViterbiEnvelopeWeightFunction { + ViterbiEnvelopeWeightFunction(const SparseVector<double>& ori, + const SparseVector<double>& dir) : origin(ori), direction(dir) {} + ViterbiEnvelope operator()(const Hypergraph::Edge& e) const; + const SparseVector<double> origin; + const SparseVector<double> direction; +}; + +#endif |