[Boost-commit] svn:boost r71405 - in trunk/boost/math/special_functions: . detail

Subject: [Boost-commit] svn:boost r71405 - in trunk/boost/math/special_functions: . detail
From: john_at_[hidden]
Date: 2011-04-21 14:11:37

Author: johnmaddock
Date: 2011-04-21 14:11:37 EDT (Thu, 21 Apr 2011)
New Revision: 71405
URL: http://svn.boost.org/trac/boost/changeset/71405

Log:
Change fp_traits to handle sign manipulation separately from fp-classification.
Fixes some Linux/GCC regressions but not yet all.
Text files modified: 
   trunk/boost/math/special_functions/detail/fp_traits.hpp |     3 ++-                                     
   trunk/boost/math/special_functions/sign.hpp             |    30 +++++++++++-------------------          
   2 files changed, 13 insertions(+), 20 deletions(-)

Modified: trunk/boost/math/special_functions/detail/fp_traits.hpp
==============================================================================
--- trunk/boost/math/special_functions/detail/fp_traits.hpp	(original)
+++ trunk/boost/math/special_functions/detail/fp_traits.hpp	2011-04-21 14:11:37 EDT (Thu, 21 Apr 2011)
@@ -552,12 +552,13 @@
 
 template<class T> struct fp_traits
 {
+    typedef BOOST_DEDUCED_TYPENAME size_to_precision<sizeof(T), ::boost::is_floating_point<T>::value>::type precision;
 #if defined(BOOST_MATH_USE_STD_FPCLASSIFY) && !defined(BOOST_MATH_DISABLE_STD_FPCLASSIFY)
     typedef typename select_native<T>::type type;
 #else
-    typedef BOOST_DEDUCED_TYPENAME size_to_precision<sizeof(T), ::boost::is_floating_point<T>::value>::type precision;
     typedef fp_traits_non_native<T, precision> type;
 #endif
+    typedef fp_traits_non_native<T, precision> sign_change_type;
 };
 
 //------------------------------------------------------------------------------

Modified: trunk/boost/math/special_functions/sign.hpp
==============================================================================
--- trunk/boost/math/special_functions/sign.hpp	(original)
+++ trunk/boost/math/special_functions/sign.hpp	2011-04-21 14:11:37 EDT (Thu, 21 Apr 2011)
@@ -66,14 +66,6 @@
 
     // Changesign
 
-#ifdef BOOST_MATH_USE_STD_FPCLASSIFY
-    template<class T> 
-    inline int changesign_impl(T x, native_tag const&)
-    {
-         return -x;
-    }
-#endif
-
     template<class T>
     inline T (changesign_impl)(T x, generic_tag<true> const&)
     {
@@ -90,7 +82,7 @@
     template<class T>
     inline T changesign_impl(T x, ieee_copy_all_bits_tag const&)
     {
-        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;
+        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::sign_change_type traits;
 
         BOOST_DEDUCED_TYPENAME traits::bits a;
         traits::get_bits(x,a);
@@ -102,7 +94,7 @@
     template<class T>
     inline T (changesign_impl)(T x, ieee_copy_leading_bits_tag const&)
     {
-        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;
+        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::sign_change_type traits;
 
         BOOST_DEDUCED_TYPENAME traits::bits a;
         traits::get_bits(x,a);
@@ -115,7 +107,7 @@
 }   // 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;
@@ -128,22 +120,22 @@
    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)
-{
-   BOOST_MATH_STD_USING
-      return fabs(x) * ((boost::math::signbit)(y) ? -1 : 1);
-}
-
 template<class T> T (changesign)(T x)
 { //!< \brief return unchanged binary pattern of x, except for change of sign bit. 
-   typedef typename detail::fp_traits<T>::type traits;
+   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;
 
    return detail::changesign_impl(x, method());
 }
 
+template <class T>
+inline T copysign BOOST_NO_MACRO_EXPAND(const T& x, const T& y)
+{
+   BOOST_MATH_STD_USING
+   return (boost::math::signbit)(x) != (boost::math::signbit)(y) ? (boost::math::changesign)(x) : x;
+}
+
 } // namespace math
 } // namespace boost