Added boost header

test/external/boost/math/complex/acosh.hpp

@@ -0,0 +1,34 @@
+//  (C) Copyright John Maddock 2005.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_MATH_COMPLEX_ACOSH_INCLUDED
+#define BOOST_MATH_COMPLEX_ACOSH_INCLUDED
+
+#ifndef BOOST_MATH_COMPLEX_DETAILS_INCLUDED
+#  include <boost/math/complex/details.hpp>
+#endif
+#ifndef BOOST_MATH_COMPLEX_ATANH_INCLUDED
+#  include <boost/math/complex/acos.hpp>
+#endif
+
+namespace boost{ namespace math{
+
+template<class T> 
+inline std::complex<T> acosh(const std::complex<T>& z)
+{
+   //
+   // We use the relation acosh(z) = +-i acos(z)
+   // Choosing the sign of multiplier to give real(acosh(z)) >= 0
+   // as well as compatibility with C99.
+   //
+   std::complex<T> result = boost::math::acos(z);
+   if(!detail::test_is_nan(result.imag()) && result.imag() <= 0)
+      return detail::mult_i(result);
+   return detail::mult_minus_i(result);
+}
+
+} } // namespaces
+
+#endif // BOOST_MATH_COMPLEX_ACOSH_INCLUDED