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authorChanho Park <chanho61.park@samsung.com>2014-12-11 09:55:56 (GMT)
committerChanho Park <chanho61.park@samsung.com>2014-12-11 09:55:56 (GMT)
commit08c1e93fa36a49f49325a07fe91ff92c964c2b6c (patch)
tree7a7053ceb8874b28ec4b868d4c49b500008a102e /boost/math/special_functions/sign.hpp
parentbb4dd8289b351fae6b55e303f189127a394a1edd (diff)
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Imported Upstream version 1.57.0upstream/1.57.0
Diffstat (limited to 'boost/math/special_functions/sign.hpp')
-rw-r--r--boost/math/special_functions/sign.hpp71
1 files changed, 60 insertions, 11 deletions
diff --git a/boost/math/special_functions/sign.hpp b/boost/math/special_functions/sign.hpp
index 6de88b2..f5c562d 100644
--- a/boost/math/special_functions/sign.hpp
+++ b/boost/math/special_functions/sign.hpp
@@ -31,7 +31,10 @@ namespace detail {
}
#endif
- template<class T>
+ // Generic versions first, note that these do not handle
+ // signed zero or NaN.
+
+ template<class T>
inline int signbit_impl(T x, generic_tag<true> const&)
{
return x < 0;
@@ -43,7 +46,25 @@ namespace detail {
return x < 0;
}
- template<class T>
+#if defined(__GNUC__) && (LDBL_MANT_DIG == 106)
+ //
+ // Special handling for GCC's "double double" type,
+ // in this case the sign is the same as the sign we
+ // get by casting to double, no overflow/underflow
+ // can occur since the exponents are the same magnitude
+ // for the two types:
+ //
+ inline int signbit_impl(long double x, generic_tag<true> const&)
+ {
+ return boost::math::signbit(static_cast<double>(x));
+ }
+ inline int signbit_impl(long double x, generic_tag<false> const&)
+ {
+ return boost::math::signbit(static_cast<double>(x));
+ }
+#endif
+
+ template<class T>
inline int signbit_impl(T x, ieee_copy_all_bits_tag const&)
{
typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;
@@ -65,6 +86,9 @@ namespace detail {
}
// Changesign
+
+ // Generic versions first, note that these do not handle
+ // signed zero or NaN.
template<class T>
inline T (changesign_impl)(T x, generic_tag<true> const&)
@@ -77,7 +101,27 @@ namespace detail {
{
return -x;
}
-
+#if defined(__GNUC__) && (LDBL_MANT_DIG == 106)
+ //
+ // Special handling for GCC's "double double" type,
+ // in this case we need to change the sign of both
+ // components of the "double double":
+ //
+ inline long double (changesign_impl)(long double x, generic_tag<true> const&)
+ {
+ double* pd = reinterpret_cast<double*>(&x);
+ pd[0] = boost::math::changesign(pd[0]);
+ pd[1] = boost::math::changesign(pd[1]);
+ return x;
+ }
+ inline long double (changesign_impl)(long double x, generic_tag<false> const&)
+ {
+ double* pd = reinterpret_cast<double*>(&x);
+ pd[0] = boost::math::changesign(pd[0]);
+ pd[1] = boost::math::changesign(pd[1]);
+ return x;
+ }
+#endif
template<class T>
inline T changesign_impl(T x, ieee_copy_all_bits_tag const&)
@@ -110,8 +154,9 @@ template<class T> int (signbit)(T x)
{
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>
@@ -120,20 +165,24 @@ inline int sign BOOST_NO_MACRO_EXPAND(const T& z)
return (z == 0) ? 0 : (boost::math::signbit)(z) ? -1 : 1;
}
-template<class T> T (changesign)(const T& x)
+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 boost::is_floating_point<T>::type fp_tag;
+ typedef typename tools::promote_args_permissive<T>::type result_type;
- return detail::changesign_impl(x, method());
+ return detail::changesign_impl(static_cast<result_type>(x), method());
}
-template <class T>
-inline T copysign BOOST_NO_MACRO_EXPAND(const T& x, const T& y)
+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 (boost::math::signbit)(x) != (boost::math::signbit)(y) ? (boost::math::changesign)(x) : x;
+ 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