Merge pull request #158 from BoostGSoC21/igamma_inv

Fix #131 via tune elem and special funcs

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail.hpp

@@ -95,11 +95,13 @@ struct exact_arithmetic
 
    static constexpr auto normalize(float_pair& result, float_type a, float_type b) -> void
    {
-      // Converts a pair of floats to standard form.
-      const float_pair tmp = fast_sum(a, b);
+      float_type u { a + b };
+      float_type v { a - u };
 
-      result.first  = tmp.first;
-      result.second = tmp.second;
+      v = v + b;
+
+      result.first  = u;
+      result.second = v;
    }
 
    static constexpr auto split(const float_type& a) -> float_pair

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath.hpp

@@ -10,6 +10,7 @@
 
 #include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_fabs.hpp>
 #include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_fma.hpp>
+#include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_fpclassify.hpp>
 #include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_frexp.hpp>
 #include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_isinf.hpp>
 #include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_isnan.hpp>

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_fpclassify.hpp

@@ -0,0 +1,52 @@
+///////////////////////////////////////////////////////////////////////////////
+//  Copyright Christopher Kormanyos 2024.
+//  Distributed under 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_MP_CPP_DF_QF_DETAIL_CCMATH_FPCLASSIFY_2024_12_26_HPP
+#define BOOST_MP_CPP_DF_QF_DETAIL_CCMATH_FPCLASSIFY_2024_12_26_HPP
+
+#include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_fabs.hpp>
+#include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_isinf.hpp>
+#include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_isnan.hpp>
+#include <boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_limits.hpp>
+
+#include <cmath>
+
+namespace boost { namespace multiprecision { namespace backends { namespace cpp_df_qf_detail { namespace ccmath {
+
+template <typename T>
+constexpr auto fpclassify(T x) -> typename std::enable_if<!std::is_integral<T>::value, int>::type
+{
+   if ((boost::multiprecision::backends::cpp_df_qf_detail::ccmath::isnan)(x))
+   {
+      return FP_NAN;
+   }
+   else if ((boost::multiprecision::backends::cpp_df_qf_detail::ccmath::isinf)(x))
+   {
+      return FP_INFINITE;
+   }
+   else
+   {
+      const T fabs_x { boost::multiprecision::backends::cpp_df_qf_detail::ccmath::fabs(x) };
+
+      if (fabs_x == T(0))
+      {
+         return FP_ZERO;
+      }
+      else if ((fabs_x > 0) && (fabs_x < (boost::multiprecision::backends::cpp_df_qf_detail::ccmath::numeric_limits<T>::min)()))
+      {
+         return FP_SUBNORMAL;
+      }
+      else
+      {
+         return FP_NORMAL;
+      }
+   }
+}
+
+} } } } } // namespace boost::multiprecision::backends::cpp_df_qf_detail::ccmath
+
+#endif // BOOST_MP_CPP_DF_QF_DETAIL_CCMATH_FPCLASSIFY_2024_12_26_HPP

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_isnan.hpp

@@ -11,7 +11,7 @@
 namespace boost { namespace multiprecision { namespace backends { namespace cpp_df_qf_detail { namespace ccmath {
 
 template <class FloatingPointType>
-constexpr bool isnan(FloatingPointType x)
+constexpr auto isnan(FloatingPointType x) -> bool
 {
    return (x != x);
 }