1 files changed, 41 insertions, 0 deletions
diff --git a/moses/TranslationModel/UG/sapt_pscore_rareness.h b/moses/TranslationModel/UG/sapt_pscore_rareness.h
new file mode 100644
index 000000000..58f204c88
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+++ b/moses/TranslationModel/UG/sapt_pscore_rareness.h
@@ -0,0 +1,41 @@
+// -*- c++ -*-
+// Phrase scorer that rewards the number of phrase pair occurrences in a bitext
+// with the asymptotic function x/(j+x) where x > 0 is a function
+// parameter that determines the steepness of the rewards curve
+// written by Ulrich Germann 
+
+#include "sapt_pscore_base.h"
+#include <boost/dynamic_bitset.hpp>
+
+using namespace std;
+namespace Moses {
+  namespace bitext  {
+    
+    // rareness penalty: x/(n+x)
+    template<typename Token>
+    class
+    PScoreRareness : public SingleRealValuedParameterPhraseScorerFamily<Token>
+    {
+    public:
+      PScoreRareness(string const spec) 
+      {
+	this->m_tag = "rare";
+	this->init(spec);
+      }
+
+      bool
+      isLogVal(int i) const { return false; } 
+
+      void 
+      operator()(Bitext<Token> const& bt, 
+		 PhrasePair<Token>& pp, 
+		 vector<float> * dest = NULL) const
+      {
+	if (!dest) dest = &pp.fvals;
+	size_t i = this->m_index;
+	BOOST_FOREACH(float const x, this->m_x)
+	  (*dest).at(i++) = x/(x + pp.joint);
+      }
+    };
+  } // namespace bitext
+} // namespace Moses