Merge branch 'master' of github.com:redpony/cdec

1 files changed, 57 insertions, 0 deletions

diff --git a/decoder/ffset.h b/decoder/ffset.h
new file mode 100644
index 00000000..28aef667
--- /dev/null
+++ b/decoder/ffset.h
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+#ifndef _FFSET_H_
+#define _FFSET_H_
+
+#include <vector>
+#include "value_array.h"
+#include "prob.h"
+
+namespace HG { struct Edge; struct Node; }
+class Hypergraph;
+class FeatureFunction;
+class SentenceMetadata;
+class FeatureFunction;  // see definition below
+
+// TODO let states be dynamically sized
+typedef ValueArray<uint8_t> FFState; // this is a fixed array, but about 10% faster than string
+
+//FIXME: only context.data() is required to be contiguous, and it becomes invalid after next string operation.  use ValueArray instead? (higher performance perhaps, save a word due to fixed size)
+typedef std::vector<FFState> FFStates;
+
+// this class is a set of FeatureFunctions that can be used to score, rescore,
+// etc. a (translation?) forest
+class ModelSet {
+ public:
+  ModelSet(const std::vector<double>& weights,
+           const std::vector<const FeatureFunction*>& models);
+
+  // sets edge->feature_values_ and edge->edge_prob_
+  // NOTE: edge must not necessarily be in hg.edges_ but its TAIL nodes
+  // must be.  edge features are supposed to be overwritten, not added to (possibly because rule features aren't in ModelSet so need to be left alone
+  void AddFeaturesToEdge(const SentenceMetadata& smeta,
+                         const Hypergraph& hg,
+                         const FFStates& node_states,
+                         HG::Edge* edge,
+                         FFState* residual_context,
+                         prob_t* combination_cost_estimate = NULL) const;
+
+  //this is called INSTEAD of above when result of edge is goal (must be a unary rule - i.e. one variable, but typically it's assumed that there are no target terminals either (e.g. for LM))
+  void AddFinalFeatures(const FFState& residual_context,
+                        HG::Edge* edge,
+                        SentenceMetadata const& smeta) const;
+
+  // this is called once before any feature functions apply to a hypergraph
+  // it can be used to initialize sentence-specific data structures
+  void PrepareForInput(const SentenceMetadata& smeta);
+
+  bool empty() const { return models_.empty(); }
+
+  bool stateless() const { return !state_size_; }
+
+ private:
+  std::vector<const FeatureFunction*> models_;
+  const std::vector<double>& weights_;
+  int state_size_;
+  std::vector<int> model_state_pos_;
+};
+
+#endif