1 files changed, 110 insertions, 0 deletions
diff --git a/extools/extract.h b/extools/extract.h
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+++ b/extools/extract.h
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+#ifndef _EXTRACT_H_
+#define _EXTRACT_H_
+
+#include <iostream>
+#include <utility>
+#include <vector>
+#include "array2d.h"
+#include "wordid.h"
+#include "sparse_vector.h"
+
+struct AnnotatedParallelSentence;
+
+// usually represents a consistent phrase, which may
+// be annotated with a type (cat)
+// inside the rule extractor, this class is also used to represent a word
+// in a partial rule.
+struct ParallelSpan {
+  // i1 = i of f side
+  // i2 = j of f side
+  // j1 = i of e side
+  // j2 = j of e side
+  short i1,i2,j1,j2;
+  // cat is set by AnnotatePhrasesWithCategoryTypes, otherwise it's 0
+  WordID cat;  // category type of span (also overloaded by RuleItem class
+               //                        to be a word ID)
+  ParallelSpan() : i1(-1), i2(-1), j1(-1), j2(-1), cat() {}
+  // used by Rule class to represent a terminal symbol:
+  explicit ParallelSpan(WordID w) : i1(-1), i2(-1), j1(-1), j2(-1), cat(w) {}
+  ParallelSpan(int pi1, int pi2, int pj1, int pj2) : i1(pi1), i2(pi2), j1(pj1), j2(pj2), cat() {}
+  ParallelSpan(int pi1, int pi2, int pj1, int pj2, WordID c) : i1(pi1), i2(pi2), j1(pj1), j2(pj2), cat(c) {}
+
+  // ParallelSpan is used in the Rule class where it is
+  // overloaded to also represent terminal symbols
+  inline bool IsVariable() const { return i1 != -1; }
+};
+
+// rule extraction logic lives here. this has no data, it's just got
+// static member functions.
+struct Extract {
+  // RuleObserver's CountRule is called for each rule extracted
+  // implement CountRuleImpl to do things like count the rules,
+  // write them to a file, etc.
+  struct RuleObserver {
+    RuleObserver() : count() {}
+    virtual void CountRule(WordID lhs,
+                           const std::vector<WordID>& rhs_f,
+                           const std::vector<WordID>& rhs_e,
+                           const std::vector<std::pair<short, short> >& fe_terminal_alignments) {
+      ++count;
+      CountRuleImpl(lhs, rhs_f, rhs_e, fe_terminal_alignments);
+    }
+    virtual ~RuleObserver();
+
+   protected:
+    virtual void CountRuleImpl(WordID lhs,
+                           const std::vector<WordID>& rhs_f,
+                           const std::vector<WordID>& rhs_e,
+                           const std::vector<std::pair<short, short> >& fe_terminal_alignments) = 0;
+   private:
+    int count;
+  };
+
+  // given a set of "tight" phrases and the aligned sentence they were
+  // extracted from, "loosen" them
+  static void LoosenPhraseBounds(const AnnotatedParallelSentence& sentence,
+                                 const int max_base_phrase_size,
+                                 std::vector<ParallelSpan>* phrases);
+
+  // extract all consistent phrase pairs, up to size max_base_phrase_size
+  // (on the source side). these phrases will be "tight".
+  static void ExtractBasePhrases(const int max_base_phrase_size,
+                        const AnnotatedParallelSentence& sentence,
+                        std::vector<ParallelSpan>* phrases);
+
+  // this uses the TARGET span (i,j) to annotate phrases, will copy
+  // phrases if there is more than one annotation.
+  // TODO: support source annotation
+  static void AnnotatePhrasesWithCategoryTypes(const WordID default_cat,
+                                      const Array2D<std::vector<WordID> >& types,
+                                      std::vector<ParallelSpan>* phrases);
+
+  // use the Chiang (2007) extraction logic to extract consistent subphrases
+  // observer->CountRule is called once for each rule extracted
+  static void ExtractConsistentRules(const AnnotatedParallelSentence& sentence,
+                          const std::vector<ParallelSpan>& phrases,
+                          const int max_vars,
+                          const int max_syms,
+                          const bool permit_adjacent_nonterminals,
+                          const bool require_aligned_terminal,
+                          RuleObserver* observer);
+};
+
+// represents statistics / information about a rule pair
+struct RuleStatistics {
+  SparseVector<float> counts;
+  std::vector<std::pair<short,short> > aligns;
+  RuleStatistics() {}
+  RuleStatistics(int name, float val, const std::vector<std::pair<short,short> >& al) :
+      aligns(al) {
+    counts.set_value(name, val);
+  }
+  void ParseRuleStatistics(const char* buf, int start, int end);
+  RuleStatistics& operator+=(const RuleStatistics& rhs) {
+    counts += rhs.counts;
+    return *this;
+  }
+};
+std::ostream& operator<<(std::ostream& os, const RuleStatistics& s);
+
+#endif