fixed CreateViterbiHypergraph (old impl did not work), so --show_derivation works

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@408 ec762483-ff6d-05da-a07a-a48fb63a330f

1 files changed, 18 insertions, 1 deletions

diff --git a/decoder/indices_after.h b/decoder/indices_after.h
index ad94c576..dec94cc0 100755
--- a/decoder/indices_after.h
+++ b/decoder/indices_after.h
@@ -3,6 +3,7 @@
 
 #include <boost/config.hpp> // STATIC_CONSTANT
 #include <algorithm> //swap
+#include <iterator>
 
 // iterator wrapper.  inverts boolean value.
 template <class AB>
@@ -47,7 +48,8 @@ unsigned new_indices(KEEP keep,O out) {
   return new_indices(keep.begin(),keep.end(),out);
 }
 
-// given a vector and a parallel sequence of bools where true means keep, keep only the marked elements while maintaining order
+// given a vector and a parallel sequence of bools where true means keep, keep only the marked elements while maintaining order.
+// this is done with a parallel sequence to the input, marked with positions the kept items would map into in a destination array, with removed items marked with the index -1.  the reverse would be more compact (parallel to destination array, index of input item that goes into it) but would require the input sequence be random access.
 struct indices_after
 {
   BOOST_STATIC_CONSTANT(unsigned,REMOVED=(unsigned)-1);
@@ -142,6 +144,21 @@ struct indices_after
         to[map[i]]=v[i];
   }
 
+  //transform collection of indices into what we're remapping.  (input/output iterators)
+  template <class IndexI,class IndexO>
+  void reindex(IndexI i,IndexI const end,IndexO o) const {
+    for(;i<end;++i) {
+      unsigned m=map[*i];
+      if (m!=REMOVED)
+        *o++=m;
+    }
+  }
+
+  template <class VecI,class VecO>
+  void reindex_push_back(VecI const& i,VecO &o) const {
+    reindex(i.begin(),i.end(),std::back_inserter(o));
+  }
+
 private:
   indices_after(indices_after const& o)
   {