From 72c95383e03ea86d6a154faa7ec684d7f4d1e750 Mon Sep 17 00:00:00 2001
From: Geoffrey Lalonde <lalondegeoffrey@gmail.com>
Date: Wed, 15 Jun 2016 23:33:19 -0700
Subject: [PATCH] Add autodiff coverage for standard library hyperbolic
 functions, and tests. * * * Corrected tanh derivatived, moved test
 definitions. * * * Added more test cases, removed lingering lines

---
 .../Eigen/src/AutoDiff/AutoDiffScalar.h       | 15 ++++++++
 unsupported/test/autodiff_scalar.cpp          | 35 +++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h b/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h
index 089042751..1c60e96a7 100755
--- a/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h
+++ b/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h
@@ -646,6 +646,21 @@ EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(acos,
   using std::acos;
   return ReturnType(acos(x.value()),x.derivatives() * (Scalar(-1)/sqrt(1-numext::abs2(x.value()))));)
 
+EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(tanh,
+  using std::cosh;
+  using std::tanh;
+  return ReturnType(tanh(x.value()),x.derivatives() * (Scalar(1)/numext::abs2(cosh(x.value()))));)
+
+EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(sinh,
+  using std::sinh;
+  using std::cosh;
+  return ReturnType(sinh(x.value()),x.derivatives() * cosh(x.value()));)
+
+EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(cosh,
+  using std::sinh;
+  using std::cosh;
+  return ReturnType(cosh(x.value()),x.derivatives() * sinh(x.value()));)
+
 #undef EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY
 
 template<typename DerType> struct NumTraits<AutoDiffScalar<DerType> >
diff --git a/unsupported/test/autodiff_scalar.cpp b/unsupported/test/autodiff_scalar.cpp
index c631c734a..4df2f5c57 100644
--- a/unsupported/test/autodiff_scalar.cpp
+++ b/unsupported/test/autodiff_scalar.cpp
@@ -36,13 +36,48 @@ template<typename Scalar> void check_atan2()
   VERIFY_IS_APPROX(res.derivatives(), x.derivatives());
 }
 
+template<typename Scalar> void check_hyperbolic_functions()
+{
+  using std::sinh;
+  using std::cosh;
+  using std::tanh;
+  typedef Matrix<Scalar, 1, 1> Deriv1;
+  typedef AutoDiffScalar<Deriv1> AD;
+  Deriv1 p = Deriv1::Random();
+  AD val(p.x(),Deriv1::UnitX());
 
+  Scalar cosh_px = std::cosh(p.x());
+  AD res1 = tanh(val);
+  VERIFY_IS_APPROX(res1.value(), std::tanh(p.x()));
+  VERIFY_IS_APPROX(res1.derivatives().x(), Scalar(1.0) / (cosh_px * cosh_px));
 
+  AD res2 = sinh(val);
+  VERIFY_IS_APPROX(res2.value(), std::sinh(p.x()));
+  VERIFY_IS_APPROX(res2.derivatives().x(), cosh_px);
+
+  AD res3 = cosh(val);
+  VERIFY_IS_APPROX(res3.value(), cosh_px);
+  VERIFY_IS_APPROX(res3.derivatives().x(), std::sinh(p.x()));
+
+  // Check constant values.
+  const Scalar sample_point = Scalar(1) / Scalar(3); 
+  val = AD(sample_point,Deriv1::UnitX());
+  res1 = tanh(val);
+  VERIFY_IS_APPROX(res1.derivatives().x(), Scalar(0.896629559604914));
+
+  res2 = sinh(val);
+  VERIFY_IS_APPROX(res2.derivatives().x(), Scalar(1.056071867829939));
+
+  res3 = cosh(val);
+  VERIFY_IS_APPROX(res3.derivatives().x(), Scalar(0.339540557256150));
+}
 
 void test_autodiff_scalar()
 {
   for(int i = 0; i < g_repeat; i++) {
     CALL_SUBTEST_1( check_atan2<float>() );
     CALL_SUBTEST_2( check_atan2<double>() );
+    CALL_SUBTEST_3( check_hyperbolic_functions<float>() );
+    CALL_SUBTEST_4( check_hyperbolic_functions<double>() );
   }
 }