libstdc++
numeric
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00001 // <numeric> -*- C++ -*-
00002 
00003 // Copyright (C) 2001-2019 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the
00007 // terms of the GNU General Public License as published by the
00008 // Free Software Foundation; either version 3, or (at your option)
00009 // any later version.
00010 
00011 // This library is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /*
00026  *
00027  * Copyright (c) 1994
00028  * Hewlett-Packard Company
00029  *
00030  * Permission to use, copy, modify, distribute and sell this software
00031  * and its documentation for any purpose is hereby granted without fee,
00032  * provided that the above copyright notice appear in all copies and
00033  * that both that copyright notice and this permission notice appear
00034  * in supporting documentation.  Hewlett-Packard Company makes no
00035  * representations about the suitability of this software for any
00036  * purpose.  It is provided "as is" without express or implied warranty.
00037  *
00038  *
00039  * Copyright (c) 1996,1997
00040  * Silicon Graphics Computer Systems, Inc.
00041  *
00042  * Permission to use, copy, modify, distribute and sell this software
00043  * and its documentation for any purpose is hereby granted without fee,
00044  * provided that the above copyright notice appear in all copies and
00045  * that both that copyright notice and this permission notice appear
00046  * in supporting documentation.  Silicon Graphics makes no
00047  * representations about the suitability of this software for any
00048  * purpose.  It is provided "as is" without express or implied warranty.
00049  */
00050 
00051 /** @file include/numeric
00052  *  This is a Standard C++ Library header.
00053  */
00054 
00055 #ifndef _GLIBCXX_NUMERIC
00056 #define _GLIBCXX_NUMERIC 1
00057 
00058 #pragma GCC system_header
00059 
00060 #include <bits/c++config.h>
00061 #include <bits/stl_iterator_base_types.h>
00062 #include <bits/stl_numeric.h>
00063 
00064 #ifdef _GLIBCXX_PARALLEL
00065 # include <parallel/numeric>
00066 #endif
00067 
00068 /**
00069  * @defgroup numerics Numerics
00070  *
00071  * Components for performing numeric operations. Includes support for
00072  * for complex number types, random number generation, numeric
00073  * (n-at-a-time) arrays, generalized numeric algorithms, and special
00074  * math functions.
00075  */
00076 
00077 #if __cplusplus >= 201402L
00078 #include <type_traits>
00079 
00080 namespace std _GLIBCXX_VISIBILITY(default)
00081 {
00082 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00083 
00084 namespace __detail
00085 {
00086   // std::abs is not constexpr and doesn't support unsigned integers.
00087   template<typename _Tp>
00088     constexpr
00089     enable_if_t<__and_<is_integral<_Tp>, is_signed<_Tp>>::value, _Tp>
00090     __abs_integral(_Tp __val)
00091     { return __val < 0 ? -__val : __val; }
00092 
00093   template<typename _Tp>
00094     constexpr
00095     enable_if_t<__and_<is_integral<_Tp>, is_unsigned<_Tp>>::value, _Tp>
00096     __abs_integral(_Tp __val)
00097     { return __val; }
00098 
00099   void __abs_integral(bool) = delete;
00100 
00101   template<typename _Mn, typename _Nn>
00102     constexpr common_type_t<_Mn, _Nn>
00103     __gcd(_Mn __m, _Nn __n)
00104     {
00105       return __m == 0 ? __detail::__abs_integral(__n)
00106         : __n == 0 ? __detail::__abs_integral(__m)
00107         : __detail::__gcd(__n, __m % __n);
00108     }
00109 
00110   /// Least common multiple
00111   template<typename _Mn, typename _Nn>
00112     constexpr common_type_t<_Mn, _Nn>
00113     __lcm(_Mn __m, _Nn __n)
00114     {
00115       return (__m != 0 && __n != 0)
00116         ? (__detail::__abs_integral(__m) / __detail::__gcd(__m, __n))
00117           * __detail::__abs_integral(__n)
00118         : 0;
00119     }
00120 } // namespace __detail
00121 
00122 #if __cplusplus >= 201703L
00123 
00124 #define __cpp_lib_gcd_lcm 201606
00125 // These were used in drafts of SD-6:
00126 #define __cpp_lib_gcd 201606
00127 #define __cpp_lib_lcm 201606
00128 
00129   /// Greatest common divisor
00130   template<typename _Mn, typename _Nn>
00131     constexpr common_type_t<_Mn, _Nn>
00132     gcd(_Mn __m, _Nn __n)
00133     {
00134       static_assert(is_integral_v<_Mn>, "gcd arguments are integers");
00135       static_assert(is_integral_v<_Nn>, "gcd arguments are integers");
00136       static_assert(!is_same_v<remove_cv_t<_Mn>, bool>,
00137                     "gcd arguments are not bools");
00138       static_assert(!is_same_v<remove_cv_t<_Nn>, bool>,
00139                     "gcd arguments are not bools");
00140       return __detail::__gcd(__m, __n);
00141     }
00142 
00143   /// Least common multiple
00144   template<typename _Mn, typename _Nn>
00145     constexpr common_type_t<_Mn, _Nn>
00146     lcm(_Mn __m, _Nn __n)
00147     {
00148       static_assert(is_integral_v<_Mn>, "lcm arguments are integers");
00149       static_assert(is_integral_v<_Nn>, "lcm arguments are integers");
00150       static_assert(!is_same_v<remove_cv_t<_Mn>, bool>,
00151                     "lcm arguments are not bools");
00152       static_assert(!is_same_v<remove_cv_t<_Nn>, bool>,
00153                     "lcm arguments are not bools");
00154       return __detail::__lcm(__m, __n);
00155     }
00156 
00157 #endif // C++17
00158 
00159 #if __cplusplus > 201703L
00160   // midpoint
00161 # define __cpp_lib_interpolate 201902L
00162 
00163 template<typename _Tp>
00164     constexpr
00165     enable_if_t<__and_v<is_arithmetic<_Tp>, is_same<remove_cv_t<_Tp>, _Tp>,
00166                         __not_<is_same<_Tp, bool>>>,
00167                 _Tp>
00168     midpoint(_Tp __a, _Tp __b) noexcept
00169     {
00170       if constexpr (is_integral_v<_Tp>)
00171         {
00172           using _Up = make_unsigned_t<_Tp>;
00173 
00174           int __k = 1;
00175           _Up __m = __a;
00176           _Up __M = __b;
00177           if (__a > __b)
00178             {
00179               __k = -1;
00180               __m = __b;
00181               __M = __a;
00182             }
00183           return __a + __k * _Tp(_Up(__M - __m) / 2);
00184         }
00185       else
00186         {
00187           return __builtin_isnormal(__a) && __builtin_isnormal(__b)
00188             ? __a / 2 + __b / 2
00189             : (__a + __b) / 2;
00190         }
00191     }
00192 
00193   template<typename _Tp>
00194     constexpr
00195     enable_if_t<__and_v<is_object<_Tp>, bool_constant<sizeof(_Tp) != 0>>, _Tp*>
00196     midpoint(_Tp* __a, _Tp* __b) noexcept
00197     {
00198       return __a  + (__b - __a) / 2;
00199     }
00200 #endif // C++20
00201 
00202 _GLIBCXX_END_NAMESPACE_VERSION
00203 } // namespace std
00204 
00205 #endif // C++14
00206 
00207 #if __cplusplus > 201402L
00208 // Parallel STL algorithms
00209 # if __PSTL_EXECUTION_POLICIES_DEFINED
00210 // If <execution> has already been included, pull in implementations
00211 #  include <pstl/glue_numeric_impl.h>
00212 # else
00213 // Otherwise just pull in forward declarations
00214 #  include <pstl/glue_numeric_defs.h>
00215 #  define __PSTL_NUMERIC_FORWARD_DECLARED 1
00216 # endif
00217 
00218 // Feature test macro for parallel algorithms
00219 # define __cpp_lib_parallel_algorithm 201703L
00220 #endif // C++17
00221 
00222 #endif /* _GLIBCXX_NUMERIC */