optional variational bayes

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@734 ec762483-ff6d-05da-a07a-a48fb63a330f

1 files changed, 14 insertions, 0 deletions

diff --git a/training/ttables.h b/training/ttables.h
index 53f5f2ab..50d85a68 100644
--- a/training/ttables.h
+++ b/training/ttables.h
@@ -6,6 +6,7 @@
 
 #include "wordid.h"
 #include "tdict.h"
+#include "em_utils.h"
 
 class TTable {
  public:
@@ -29,6 +30,19 @@ class TTable {
   inline void Increment(const int& e, const int& f, double x) {
     counts[e][f] += x;
   }
+  void NormalizeVB(const double alpha) {
+    ttable.swap(counts);
+    for (Word2Word2Double::iterator cit = ttable.begin();
+         cit != ttable.end(); ++cit) {
+      double tot = 0;
+      Word2Double& cpd = cit->second;
+      for (Word2Double::iterator it = cpd.begin(); it != cpd.end(); ++it)
+        tot += it->second + alpha;
+      for (Word2Double::iterator it = cpd.begin(); it != cpd.end(); ++it)
+        it->second = exp(digamma(it->second + alpha) - digamma(tot));
+    }
+    counts.clear();
+  }
   void Normalize() {
     ttable.swap(counts);
     for (Word2Word2Double::iterator cit = ttable.begin();