From 7dfee211a81fdb42f250ba793a469ed8a2dcc3bf Mon Sep 17 00:00:00 2001
From: Chris Dyer <cdyer@cs.cmu.edu>
Date: Mon, 7 Feb 2011 15:03:39 -0500
Subject: more span-level features

---
 decoder/ff_spans.cc | 29 +++++++++++++++++++++++++++--
 decoder/ff_spans.h  |  1 +
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/decoder/ff_spans.cc b/decoder/ff_spans.cc
index 6fa49d45..b454c9fd 100644
--- a/decoder/ff_spans.cc
+++ b/decoder/ff_spans.cc
@@ -25,7 +25,10 @@ void SpanFeatures::TraversalFeaturesImpl(const SentenceMetadata& smeta,
   assert(edge.j_ < end_span_ids_.size());
   assert(edge.j_ >= 0);
   features->set_value(end_span_ids_[edge.j_], 1);
-
+  assert(edge.i_ < beg_span_ids_.size());
+  assert(edge.i_ >= 0);
+  features->set_value(beg_span_ids_[edge.i_], 1);
+  features->set_value(span_feats_(edge.i_,edge.j_), 1);
   if (edge.Arity() == 2) {
     const TRule& rule = *edge.rule_;
     if (rule.f_[0] == kS && rule.f_[1] == kX) {
@@ -36,15 +39,37 @@ void SpanFeatures::TraversalFeaturesImpl(const SentenceMetadata& smeta,
 
 void SpanFeatures::PrepareForInput(const SentenceMetadata& smeta) {
   const Lattice& lattice = smeta.GetSourceLattice();
-  WordID eos = TD::Convert("</s>");
+  const WordID eos = TD::Convert("</s>");
+  const WordID bos = TD::Convert("<s>");
+  beg_span_ids_.resize(lattice.size() + 1);
   end_span_ids_.resize(lattice.size() + 1);
   for (int i = 0; i <= lattice.size(); ++i) {
     WordID word = eos;
+    WordID bword = bos;
+    if (i > 0)
+      bword = lattice[i-1][0].label;
     if (i < lattice.size())
       word = lattice[i][0].label;  // rather arbitrary for lattices
     ostringstream sfid;
     sfid << "ES:" << TD::Convert(word);
     end_span_ids_[i] = FD::Convert(sfid.str());
+    ostringstream bfid;
+    bfid << "BS:" << TD::Convert(bword);
+    beg_span_ids_[i] = FD::Convert(bfid.str());
   }
+  span_feats_.resize(lattice.size() + 1, lattice.size() + 1);
+  for (int i = 0; i <= lattice.size(); ++i) {
+    WordID bword = bos;
+    if (i > 0)
+      bword = lattice[i-1][0].label;
+    for (int j = 0; j <= lattice.size(); ++j) {
+      WordID word = eos;
+      if (j < lattice.size())
+        word = lattice[j][0].label;
+      ostringstream pf;
+      pf << "SS:" << TD::Convert(bword) << "_" << TD::Convert(word);
+      span_feats_(i,j) = FD::Convert(pf.str());
+    }
+  } 
 }
 
diff --git a/decoder/ff_spans.h b/decoder/ff_spans.h
index 588956c9..0446d062 100644
--- a/decoder/ff_spans.h
+++ b/decoder/ff_spans.h
@@ -21,6 +21,7 @@ class SpanFeatures : public FeatureFunction {
   const int kX;
   Array2D<int> span_feats_;
   std::vector<int> end_span_ids_;
+  std::vector<int> beg_span_ids_;
 };
 
 #endif
-- 
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