From 2f712771059624d2c948e71fa1fb7f88888493cb Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Thu, 3 Feb 2011 14:45:21 +0100
Subject: [PATCH] add global tan function

---
 Eigen/src/Core/GlobalFunctions.h |  2 ++
 Eigen/src/Core/MathFunctions.h   | 38 ++++++++++++++++++++++++++++++++
 test/array.cpp                   |  2 ++
 3 files changed, 42 insertions(+)

diff --git a/Eigen/src/Core/GlobalFunctions.h b/Eigen/src/Core/GlobalFunctions.h
index c94b578dd..f049bff42 100644
--- a/Eigen/src/Core/GlobalFunctions.h
+++ b/Eigen/src/Core/GlobalFunctions.h
@@ -56,6 +56,7 @@ namespace std
   EIGEN_ARRAY_DECLARE_GLOBAL_STD_UNARY(imag,scalar_imag_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_STD_UNARY(sin,scalar_sin_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_STD_UNARY(cos,scalar_cos_op)
+  EIGEN_ARRAY_DECLARE_GLOBAL_STD_UNARY(tan,scalar_tan_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_STD_UNARY(exp,scalar_exp_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_STD_UNARY(log,scalar_log_op)
   EIGEN_ARRAY_DECLARE_GLOBAL_STD_UNARY(abs,scalar_abs_op)
@@ -76,6 +77,7 @@ namespace Eigen
     EIGEN_ARRAY_DECLARE_GLOBAL_EIGEN_UNARY(imag,scalar_imag_op)
     EIGEN_ARRAY_DECLARE_GLOBAL_EIGEN_UNARY(sin,scalar_sin_op)
     EIGEN_ARRAY_DECLARE_GLOBAL_EIGEN_UNARY(cos,scalar_cos_op)
+    EIGEN_ARRAY_DECLARE_GLOBAL_EIGEN_UNARY(tan,scalar_tan_op)
     EIGEN_ARRAY_DECLARE_GLOBAL_EIGEN_UNARY(exp,scalar_exp_op)
     EIGEN_ARRAY_DECLARE_GLOBAL_EIGEN_UNARY(log,scalar_log_op)
     EIGEN_ARRAY_DECLARE_GLOBAL_EIGEN_UNARY(abs,scalar_abs_op)
diff --git a/Eigen/src/Core/MathFunctions.h b/Eigen/src/Core/MathFunctions.h
index 8e7def187..4138ab436 100644
--- a/Eigen/src/Core/MathFunctions.h
+++ b/Eigen/src/Core/MathFunctions.h
@@ -567,6 +567,44 @@ inline EIGEN_MATHFUNC_RETVAL(sin, Scalar) sin(const Scalar& x)
   return EIGEN_MATHFUNC_IMPL(sin, Scalar)::run(x);
 }
 
+/****************************************************************************
+* Implementation of tan                                                  *
+****************************************************************************/
+
+template<typename Scalar, bool IsInteger>
+struct tan_default_impl
+{
+  static inline Scalar run(const Scalar& x)
+  {
+    return std::tan(x);
+  }
+};
+
+template<typename Scalar>
+struct tan_default_impl<Scalar, true>
+{
+  static inline Scalar run(const Scalar&)
+  {
+    EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar)
+    return Scalar(0);
+  }
+};
+
+template<typename Scalar>
+struct tan_impl : tan_default_impl<Scalar, NumTraits<Scalar>::IsInteger> {};
+
+template<typename Scalar>
+struct tan_retval
+{
+  typedef Scalar type;
+};
+
+template<typename Scalar>
+inline EIGEN_MATHFUNC_RETVAL(tan, Scalar) tan(const Scalar& x)
+{
+  return EIGEN_MATHFUNC_IMPL(tan, Scalar)::run(x);
+}
+
 /****************************************************************************
 * Implementation of log                                                  *
 ****************************************************************************/
diff --git a/test/array.cpp b/test/array.cpp
index 7da4c998c..26c6c33b7 100644
--- a/test/array.cpp
+++ b/test/array.cpp
@@ -173,6 +173,8 @@ template<typename ArrayType> void array_real(const ArrayType& m)
   VERIFY_IS_APPROX(m1.sin(), internal::sin(m1));
   VERIFY_IS_APPROX(m1.cos(), std::cos(m1));
   VERIFY_IS_APPROX(m1.cos(), internal::cos(m1));
+  VERIFY_IS_APPROX(m1.tan(), std::tan(m1));
+  VERIFY_IS_APPROX(m1.tan(), internal::tan(m1));
 
   VERIFY_IS_APPROX(internal::cos(m1+RealScalar(3)*m2), internal::cos((m1+RealScalar(3)*m2).eval()));
   VERIFY_IS_APPROX(std::cos(m1+RealScalar(3)*m2), std::cos((m1+RealScalar(3)*m2).eval()));