add tan function in Array world

Eigen/src/Core/Functors.h

@@ -705,6 +705,26 @@ struct functor_traits<scalar_sin_op<Scalar> >
   };
 };
 
+
+/** \internal
+  * \brief Template functor to compute the tan of a scalar
+  * \sa class CwiseUnaryOp, Cwise::tan()
+  */
+template<typename Scalar> struct scalar_tan_op {
+  EIGEN_EMPTY_STRUCT_CTOR(scalar_tan_op)
+  inline const Scalar operator() (const Scalar& a) const { return tan(a); }
+  typedef typename packet_traits<Scalar>::type Packet;
+  inline Packet packetOp(const Packet& a) const { return internal::ptan(a); }
+};
+template<typename Scalar>
+struct functor_traits<scalar_tan_op<Scalar> >
+{
+  enum {
+    Cost = 5 * NumTraits<Scalar>::MulCost,
+    PacketAccess = packet_traits<Scalar>::HasTan
+  };
+};
+
 /** \internal
   * \brief Template functor to raise a scalar to a power
   * \sa class CwiseUnaryOp, Cwise::pow

Eigen/src/Core/GenericPacketMath.h

@@ -237,6 +237,10 @@ Packet psin(const Packet& a) { return sin(a); }
 template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
 Packet pcos(const Packet& a) { return cos(a); }
 
+/** \internal \returns the tan of \a a (coeff-wise) */
+template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
+Packet ptan(const Packet& a) { return tan(a); }
+
 /** \internal \returns the exp of \a a (coeff-wise) */
 template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
 Packet pexp(const Packet& a) { return exp(a); }

Eigen/src/plugins/ArrayCwiseUnaryOps.h

@@ -93,6 +93,20 @@ sin() const
 }
 
 
+/** \returns an expression of the coefficient-wise tan of *this.
+  *
+  * Example: \include Cwise_tan.cpp
+  * Output: \verbinclude Cwise_tan.out
+  *
+  * \sa cos(), sin()
+  */
+inline const CwiseUnaryOp<internal::scalar_tan_op<Scalar>, Derived>
+tan() const
+{
+  return derived();
+}
+
+
 /** \returns an expression of the coefficient-wise power of *this to the given exponent.
   *
   * Example: \include Cwise_pow.cpp

doc/snippets/Cwise_tan.cpp

@@ -0,0 +1,2 @@
+Array3d v(M_PI, M_PI/2, M_PI/3);
+cout << v.tan() << endl;