diff --git a/Eigen/src/Core/Assign_MKL.h b/Eigen/src/Core/Assign_MKL.h
index 7772951b9..97134ffd7 100644
--- a/Eigen/src/Core/Assign_MKL.h
+++ b/Eigen/src/Core/Assign_MKL.h
@@ -202,6 +202,7 @@ EIGEN_MKL_VML_DECLARE_UNARY_CALLS_LA(asin, Asin)
 EIGEN_MKL_VML_DECLARE_UNARY_CALLS_LA(cos,  Cos)
 EIGEN_MKL_VML_DECLARE_UNARY_CALLS_LA(acos, Acos)
 EIGEN_MKL_VML_DECLARE_UNARY_CALLS_LA(tan,  Tan)
+EIGEN_MKL_VML_DECLARE_UNARY_CALLS_LA(atan,  Atan)
 //EIGEN_MKL_VML_DECLARE_UNARY_CALLS(abs,  Abs)
 EIGEN_MKL_VML_DECLARE_UNARY_CALLS_LA(exp,  Exp)
 EIGEN_MKL_VML_DECLARE_UNARY_CALLS_LA(log,  Ln)
diff --git a/Eigen/src/Core/GenericPacketMath.h b/Eigen/src/Core/GenericPacketMath.h
index 98313c68f..4523d2263 100755
--- a/Eigen/src/Core/GenericPacketMath.h
+++ b/Eigen/src/Core/GenericPacketMath.h
@@ -318,6 +318,10 @@ Packet pasin(const Packet& a) { using std::asin; return asin(a); }
 template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
 Packet pacos(const Packet& a) { using std::acos; return acos(a); }
 
+/** \internal \returns the atan of \a a (coeff-wise) */
+template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
+Packet patan(const Packet& a) { using std::atan; return atan(a); }
+
 /** \internal \returns the exp of \a a (coeff-wise) */
 template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
 Packet pexp(const Packet& a) { using std::exp; return exp(a); }
diff --git a/Eigen/src/Core/GlobalFunctions.h b/Eigen/src/Core/GlobalFunctions.h
index 2acf97723..2067a2a6e 100644
--- a/Eigen/src/Core/GlobalFunctions.h
+++ b/Eigen/src/Core/GlobalFunctions.h
@@ -45,6 +45,7 @@ namespace Eigen
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(asin,scalar_asin_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(acos,scalar_acos_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(tan,scalar_tan_op)
+  EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(atan,scalar_atan_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(exp,scalar_exp_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(log,scalar_log_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(abs,scalar_abs_op)
diff --git a/Eigen/src/Core/functors/UnaryFunctors.h b/Eigen/src/Core/functors/UnaryFunctors.h
index a0fcea3f9..ec42e6850 100644
--- a/Eigen/src/Core/functors/UnaryFunctors.h
+++ b/Eigen/src/Core/functors/UnaryFunctors.h
@@ -320,6 +320,26 @@ struct functor_traits<scalar_asin_op<Scalar> >
   };
 };
 
+
+/** \internal
+  * \brief Template functor to compute the atan of a scalar
+  * \sa class CwiseUnaryOp, ArrayBase::atan()
+  */
+template<typename Scalar> struct scalar_atan_op {
+  EIGEN_EMPTY_STRUCT_CTOR(scalar_atan_op)
+  inline const Scalar operator() (const Scalar& a) const { using std::atan; return atan(a); }
+  typedef typename packet_traits<Scalar>::type Packet;
+  inline Packet packetOp(const Packet& a) const { return internal::patan(a); }
+};
+template<typename Scalar>
+struct functor_traits<scalar_atan_op<Scalar> >
+{
+  enum {
+    Cost = 5 * NumTraits<Scalar>::MulCost,
+    PacketAccess = packet_traits<Scalar>::HasATan
+  };
+};
+
 /** \internal
   * \brief Template functor to compute the inverse of a scalar
   * \sa class CwiseUnaryOp, Cwise::inverse()
diff --git a/Eigen/src/plugins/ArrayCwiseUnaryOps.h b/Eigen/src/plugins/ArrayCwiseUnaryOps.h
index aea3375ed..d2a8ea75b 100644
--- a/Eigen/src/plugins/ArrayCwiseUnaryOps.h
+++ b/Eigen/src/plugins/ArrayCwiseUnaryOps.h
@@ -141,6 +141,15 @@ tan() const
   return derived();
 }
 
+/** \returns an expression of the coefficient-wise arc tan of *this.
+  *
+  * \sa cos(), sin(), tan()
+  */
+inline const CwiseUnaryOp<internal::scalar_atan_op<Scalar>, Derived>
+atan() const
+{
+  return derived();
+}
 
 /** \returns an expression of the coefficient-wise power of *this to the given exponent.
   *