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Merge pull request #333 from boostorg/better_arg_promotion

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Better argument promotion for float_next
This commit is contained in:
jzmaddock
2020-04-10 11:52:43 +01:00
committed by GitHub
parent 8eb40afd6b fd842536c9
commit 0cc85253e2
1 changed files with 31 additions and 3 deletions
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34
include/boost/math/special_functions/next.hpp
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@@ -9,7 +9,8 @@
#ifdef _MSC_VER
#pragma once
#endif
#include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/is_integral.hpp>
#include <boost/math/special_functions/math_fwd.hpp>
#include <boost/math/policies/error_handling.hpp>
#include <boost/math/special_functions/fpclassify.hpp>
@@ -658,8 +659,35 @@ T float_distance_imp(const T& a, const T& b, const boost::false_type&, const Pol
template <class T, class U, class Policy>
inline typename tools::promote_args<T, U>::type float_distance(const T& a, const U& b, const Policy& pol)
{
typedef typename tools::promote_args<T, U>::type result_type;
return detail::float_distance_imp(detail::normalize_value(static_cast<result_type>(a), typename detail::has_hidden_guard_digits<result_type>::type()), detail::normalize_value(static_cast<result_type>(b), typename detail::has_hidden_guard_digits<result_type>::type()), boost::integral_constant<bool, !std::numeric_limits<result_type>::is_specialized || (std::numeric_limits<result_type>::radix == 2)>(), pol);
//
// We allow ONE of a and b to be an integer type, otherwise both must be the SAME type.
//
BOOST_STATIC_ASSERT_MSG(
(boost::is_same<T, U>::value
|| (boost::is_integral<T>::value && !boost::is_integral<U>::value)
|| (!boost::is_integral<T>::value && boost::is_integral<U>::value)
|| (std::numeric_limits<T>::is_specialized && std::numeric_limits<U>::is_specialized
&& (std::numeric_limits<T>::digits == std::numeric_limits<U>::digits)
&& (std::numeric_limits<T>::radix == std::numeric_limits<U>::radix)
&& !std::numeric_limits<T>::is_integer && !std::numeric_limits<U>::is_integer)),
"Float distance between two different floating point types is undefined.");
BOOST_IF_CONSTEXPR (!boost::is_same<T, U>::value)
{
BOOST_IF_CONSTEXPR(boost::is_integral<T>::value)
{
return float_distance(static_cast<U>(a), b, pol);
}
else
{
return float_distance(a, static_cast<T>(b), pol);
}
}
else
{
typedef typename tools::promote_args<T, U>::type result_type;
return detail::float_distance_imp(detail::normalize_value(static_cast<result_type>(a), typename detail::has_hidden_guard_digits<result_type>::type()), detail::normalize_value(static_cast<result_type>(b), typename detail::has_hidden_guard_digits<result_type>::type()), boost::integral_constant<bool, !std::numeric_limits<result_type>::is_specialized || (std::numeric_limits<result_type>::radix == 2)>(), pol);
}
}
template <class T, class U>