1 files changed, 22 insertions, 0 deletions
diff --git a/training/utils/entropy.h b/training/utils/entropy.h
new file mode 100644
index 00000000..796589ca
--- /dev/null
+++ b/training/utils/entropy.h
@@ -0,0 +1,22 @@
+#ifndef _CSENTROPY_H_
+#define _CSENTROPY_H_
+
+#include <vector>
+#include "sparse_vector.h"
+
+namespace training {
+  class CandidateSet;
+
+  class CandidateSetEntropy {
+   public:
+    explicit CandidateSetEntropy(const CandidateSet& cs) : cands_(cs) {}
+    // compute the entropy (expected log likelihood) of a CandidateSet
+    // (optional) the gradient of the entropy with respect to params
+    double operator()(const std::vector<double>& params,
+                      SparseVector<double>* g = NULL) const;
+   private:
+    const CandidateSet& cands_;
+  };
+};
+
+#endif