diff --git a/unsupported/Eigen/AdolcForward b/unsupported/Eigen/AdolcForward
index 6c0a68d67..477c75378 100644
--- a/unsupported/Eigen/AdolcForward
+++ b/unsupported/Eigen/AdolcForward
@@ -79,33 +79,22 @@ namespace Eigen {
 
 } // namespace Eigen
 
-// the Adolc's type adouble is defined in the adtl namespace
-// therefore, the following internal::* functions *must* be defined
-// in the same namespace
-namespace Eigen {
+// Eigen's require a few additional functions which must be defined in the same namespace
+// than the custom scalar type own namespace
+namespace adtl {
 
-  namespace internal {
-
-    inline const adtl::adouble& conj(const adtl::adouble& x)  { return x; }
-    inline const adtl::adouble& real(const adtl::adouble& x)  { return x; }
-    inline adtl::adouble imag(const adtl::adouble&)    { return 0.; }
-    inline adtl::adouble abs(const adtl::adouble&  x)  { return adtl::fabs(x); }
-    inline adtl::adouble abs2(const adtl::adouble& x)  { return x*x; }
-    
-    using adtl::sqrt;
-    using adtl::exp;
-    using adtl::log;
-    using adtl::sin;
-    using adtl::cos;
-    using adtl::pow;
-
-  }
+inline const adouble& conj(const adouble& x)  { return x; }
+inline const adouble& real(const adouble& x)  { return x; }
+inline adouble imag(const adouble&)    { return 0.; }
+inline adouble abs(const adouble&  x)  { return fabs(x); }
+inline adouble abs2(const adouble& x)  { return x*x; }
 
 }
 
 namespace Eigen {
 
 template<> struct NumTraits<adtl::adouble>
+    : NumTraits<double>
 {
   typedef adtl::adouble Real;
   typedef adtl::adouble NonInteger;
diff --git a/unsupported/test/forward_adolc.cpp b/unsupported/test/forward_adolc.cpp
index 1971d883b..07959a668 100644
--- a/unsupported/test/forward_adolc.cpp
+++ b/unsupported/test/forward_adolc.cpp
@@ -23,11 +23,20 @@
 // Eigen. If not, see <http://www.gnu.org/licenses/>.
 
 #include "main.h"
+#include <Eigen/Dense>
+
 #define NUMBER_DIRECTIONS 16
 #include <unsupported/Eigen/AdolcForward>
 
 int adtl::ADOLC_numDir;
 
+template<typename Vector>
+EIGEN_DONT_INLINE typename Vector::Scalar foo(const Vector& p)
+{
+  typedef typename Vector::Scalar Scalar;
+  return (p-Vector(Scalar(-1),Scalar(1.))).norm() + (p.array().sqrt().abs() * p.array().sin()).sum() + p.dot(p);
+}
+
 template<typename _Scalar, int NX=Dynamic, int NY=Dynamic>
 struct TestFunc1
 {
@@ -138,4 +147,12 @@ void test_forward_adolc()
     CALL_SUBTEST(( adolc_forward_jacobian(TestFunc1<double,3,3>()) ));
     CALL_SUBTEST(( adolc_forward_jacobian(TestFunc1<double>(3,3)) ));
   }
+
+  {
+    // simple instanciation tests
+    Matrix<adtl::adouble,2,1> x;
+    foo(x);
+    Matrix<adtl::adouble,Dynamic,Dynamic> A(4,4);;
+    A.selfadjointView<Lower>().eigenvalues();
+  }
 }