Updated boost to v1.55.0

[rsem.git] / boost / math / special_functions / sign.hpp

diff --git a/boost/math/special_functions/sign.hpp b/boost/math/special_functions/sign.hpp
index 88db77729a8d1485f740bf982f334f8e8103cb3d..75fb01292a48292d400ede360065b1e7757a4112 100644 (file)
--- a/boost/math/special_functions/sign.hpp
+++ b/boost/math/special_functions/sign.hpp
@@ -1,4 +1,7 @@
 //  (C) Copyright John Maddock 2006.
+//  (C) Copyright Johan Rade 2006.
+//  (C) Copyright Paul A. Bristow 2011 (added changesign).
+
 //  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)
@@ -18,6 +21,8 @@ namespace boost{ namespace math{
 
 namespace detail {
 
+  // signbit
+
 #ifdef BOOST_MATH_USE_STD_FPCLASSIFY
     template<class T> 
     inline int signbit_impl(T x, native_tag const&)
@@ -58,14 +63,56 @@ namespace detail {
 
         return a & traits::sign ? 1 : 0;
     }
+
+    // Changesign
+
+    template<class T>
+    inline T (changesign_impl)(T x, generic_tag<true> const&)
+    {
+        return -x;
+    }
+
+    template<class T>
+    inline T (changesign_impl)(T x, generic_tag<false> const&)
+    {
+        return -x;
+    }
+
+
+    template<class T>
+    inline T changesign_impl(T x, ieee_copy_all_bits_tag const&)
+    {
+        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::sign_change_type traits;
+
+        BOOST_DEDUCED_TYPENAME traits::bits a;
+        traits::get_bits(x,a);
+        a ^= traits::sign;
+        traits::set_bits(x,a);
+        return x;
+    }
+
+    template<class T>
+    inline T (changesign_impl)(T x, ieee_copy_leading_bits_tag const&)
+    {
+        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::sign_change_type traits;
+
+        BOOST_DEDUCED_TYPENAME traits::bits a;
+        traits::get_bits(x,a);
+        a ^= traits::sign;
+        traits::set_bits(x,a);
+        return x;
+    }
+
+
 }   // namespace detail
 
 template<class T> int (signbit)(T x)
-{ //!< \brief return true if floating-point type t is NaN (Not A Number).
+{ 
    typedef typename detail::fp_traits<T>::type traits;
    typedef typename traits::method method;
-   typedef typename boost::is_floating_point<T>::type fp_tag;
-   return detail::signbit_impl(x, method());
+   // typedef typename boost::is_floating_point<T>::type fp_tag;
+   typedef typename tools::promote_args_permissive<T>::type result_type;
+   return detail::signbit_impl(static_cast<result_type>(x), method());
 }
 
 template <class T>
@@ -74,11 +121,24 @@ inline int sign BOOST_NO_MACRO_EXPAND(const T& z)
    return (z == 0) ? 0 : (boost::math::signbit)(z) ? -1 : 1;
 }
 
-template <class T>
-inline T copysign BOOST_NO_MACRO_EXPAND(const T& x, const T& y)
+template <class T> typename tools::promote_args_permissive<T>::type (changesign)(const T& x)
+{ //!< \brief return unchanged binary pattern of x, except for change of sign bit. 
+   typedef typename detail::fp_traits<T>::sign_change_type traits;
+   typedef typename traits::method method;
+   // typedef typename boost::is_floating_point<T>::type fp_tag;
+   typedef typename tools::promote_args_permissive<T>::type result_type;
+
+   return detail::changesign_impl(static_cast<result_type>(x), method());
+}
+
+template <class T, class U>
+inline typename tools::promote_args_permissive<T, U>::type 
+   copysign BOOST_NO_MACRO_EXPAND(const T& x, const U& y)
 {
    BOOST_MATH_STD_USING
-      return fabs(x) * ((boost::math::signbit)(y) ? -1 : 1);
+   typedef typename tools::promote_args_permissive<T, U>::type result_type;
+   return (boost::math::signbit)(static_cast<result_type>(x)) != (boost::math::signbit)(static_cast<result_type>(y)) 
+      ? (boost::math::changesign)(static_cast<result_type>(x)) : static_cast<result_type>(x);
 }
 
 } // namespace math