diff --git a/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h b/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h
old mode 100644
new mode 100755
index 8b58b512b..e30ad5b6d
--- a/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h
+++ b/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h
@@ -99,7 +99,11 @@ class AutoDiffScalar
     {}
 
     template<typename OtherDerType>
-    AutoDiffScalar(const AutoDiffScalar<OtherDerType>& other)
+    AutoDiffScalar(const AutoDiffScalar<OtherDerType>& other
+#ifndef EIGEN_PARSED_BY_DOXYGEN
+    , typename internal::enable_if<internal::is_same<Scalar,typename OtherDerType::Scalar>::value,void*>::type = 0
+#endif
+    )
       : m_value(other.value()), m_derivatives(other.derivatives())
     {}
 
@@ -127,6 +131,14 @@ class AutoDiffScalar
       return *this;
     }
 
+    inline AutoDiffScalar& operator=(const Scalar& other)
+    {
+      m_value = other;
+      if(m_derivatives.size()>0)
+        m_derivatives.setZero();
+      return *this;
+    }
+
 //     inline operator const Scalar& () const { return m_value; }
 //     inline operator Scalar& () { return m_value; }