libstdc++
numeric
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1 // <numeric> -*- C++ -*-
2 
3 // Copyright (C) 2001-2019 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /*
26  *
27  * Copyright (c) 1994
28  * Hewlett-Packard Company
29  *
30  * Permission to use, copy, modify, distribute and sell this software
31  * and its documentation for any purpose is hereby granted without fee,
32  * provided that the above copyright notice appear in all copies and
33  * that both that copyright notice and this permission notice appear
34  * in supporting documentation. Hewlett-Packard Company makes no
35  * representations about the suitability of this software for any
36  * purpose. It is provided "as is" without express or implied warranty.
37  *
38  *
39  * Copyright (c) 1996,1997
40  * Silicon Graphics Computer Systems, Inc.
41  *
42  * Permission to use, copy, modify, distribute and sell this software
43  * and its documentation for any purpose is hereby granted without fee,
44  * provided that the above copyright notice appear in all copies and
45  * that both that copyright notice and this permission notice appear
46  * in supporting documentation. Silicon Graphics makes no
47  * representations about the suitability of this software for any
48  * purpose. It is provided "as is" without express or implied warranty.
49  */
50 
51 /** @file include/numeric
52  * This is a Standard C++ Library header.
53  */
54 
55 #ifndef _GLIBCXX_NUMERIC
56 #define _GLIBCXX_NUMERIC 1
57 
58 #pragma GCC system_header
59 
60 #include <bits/c++config.h>
62 #include <bits/stl_numeric.h>
63 
64 #ifdef _GLIBCXX_PARALLEL
65 # include <parallel/numeric>
66 #endif
67 
68 /**
69  * @defgroup numerics Numerics
70  *
71  * Components for performing numeric operations. Includes support for
72  * for complex number types, random number generation, numeric
73  * (n-at-a-time) arrays, generalized numeric algorithms, and special
74  * math functions.
75  */
76 
77 #if __cplusplus >= 201402L
78 #include <type_traits>
79 
80 namespace std _GLIBCXX_VISIBILITY(default)
81 {
82 _GLIBCXX_BEGIN_NAMESPACE_VERSION
83 
84 namespace __detail
85 {
86  // std::abs is not constexpr and doesn't support unsigned integers.
87  template<typename _Tp>
88  constexpr
89  enable_if_t<__and_<is_integral<_Tp>, is_signed<_Tp>>::value, _Tp>
90  __abs_integral(_Tp __val)
91  { return __val < 0 ? -__val : __val; }
92 
93  template<typename _Tp>
94  constexpr
95  enable_if_t<__and_<is_integral<_Tp>, is_unsigned<_Tp>>::value, _Tp>
96  __abs_integral(_Tp __val)
97  { return __val; }
98 
99  void __abs_integral(bool) = delete;
100 
101  template<typename _Mn, typename _Nn>
102  constexpr common_type_t<_Mn, _Nn>
103  __gcd(_Mn __m, _Nn __n)
104  {
105  return __m == 0 ? __detail::__abs_integral(__n)
106  : __n == 0 ? __detail::__abs_integral(__m)
107  : __detail::__gcd(__n, __m % __n);
108  }
109 
110  /// Least common multiple
111  template<typename _Mn, typename _Nn>
112  constexpr common_type_t<_Mn, _Nn>
113  __lcm(_Mn __m, _Nn __n)
114  {
115  return (__m != 0 && __n != 0)
116  ? (__detail::__abs_integral(__m) / __detail::__gcd(__m, __n))
117  * __detail::__abs_integral(__n)
118  : 0;
119  }
120 } // namespace __detail
121 
122 #if __cplusplus >= 201703L
123 
124 #define __cpp_lib_gcd_lcm 201606
125 // These were used in drafts of SD-6:
126 #define __cpp_lib_gcd 201606
127 #define __cpp_lib_lcm 201606
128 
129  /// Greatest common divisor
130  template<typename _Mn, typename _Nn>
131  constexpr common_type_t<_Mn, _Nn>
132  gcd(_Mn __m, _Nn __n)
133  {
134  static_assert(is_integral_v<_Mn>, "gcd arguments are integers");
135  static_assert(is_integral_v<_Nn>, "gcd arguments are integers");
136  static_assert(!is_same_v<remove_cv_t<_Mn>, bool>,
137  "gcd arguments are not bools");
138  static_assert(!is_same_v<remove_cv_t<_Nn>, bool>,
139  "gcd arguments are not bools");
140  return __detail::__gcd(__m, __n);
141  }
142 
143  /// Least common multiple
144  template<typename _Mn, typename _Nn>
145  constexpr common_type_t<_Mn, _Nn>
146  lcm(_Mn __m, _Nn __n)
147  {
148  static_assert(is_integral_v<_Mn>, "lcm arguments are integers");
149  static_assert(is_integral_v<_Nn>, "lcm arguments are integers");
150  static_assert(!is_same_v<remove_cv_t<_Mn>, bool>,
151  "lcm arguments are not bools");
152  static_assert(!is_same_v<remove_cv_t<_Nn>, bool>,
153  "lcm arguments are not bools");
154  return __detail::__lcm(__m, __n);
155  }
156 
157 #endif // C++17
158 
159 #if __cplusplus > 201703L
160  // midpoint
161 # define __cpp_lib_interpolate 201902L
162 
163 template<typename _Tp>
164  constexpr
165  enable_if_t<__and_v<is_arithmetic<_Tp>, is_same<remove_cv_t<_Tp>, _Tp>,
166  __not_<is_same<_Tp, bool>>>,
167  _Tp>
168  midpoint(_Tp __a, _Tp __b) noexcept
169  {
170  if constexpr (is_integral_v<_Tp>)
171  {
172  using _Up = make_unsigned_t<_Tp>;
173 
174  int __k = 1;
175  _Up __m = __a;
176  _Up __M = __b;
177  if (__a > __b)
178  {
179  __k = -1;
180  __m = __b;
181  __M = __a;
182  }
183  return __a + __k * _Tp(_Up(__M - __m) / 2);
184  }
185  else
186  {
187  return __builtin_isnormal(__a) && __builtin_isnormal(__b)
188  ? __a / 2 + __b / 2
189  : (__a + __b) / 2;
190  }
191  }
192 
193  template<typename _Tp>
194  constexpr
195  enable_if_t<__and_v<is_object<_Tp>, bool_constant<sizeof(_Tp) != 0>>, _Tp*>
196  midpoint(_Tp* __a, _Tp* __b) noexcept
197  {
198  return __a + (__b - __a) / 2;
199  }
200 #endif // C++20
201 
202 _GLIBCXX_END_NAMESPACE_VERSION
203 } // namespace std
204 
205 #endif // C++14
206 
207 #if __cplusplus > 201402L
208 // Parallel STL algorithms
209 # if __PSTL_EXECUTION_POLICIES_DEFINED
210 // If <execution> has already been included, pull in implementations
211 # include <pstl/glue_numeric_impl.h>
212 # else
213 // Otherwise just pull in forward declarations
214 # include <pstl/glue_numeric_defs.h>
215 # define __PSTL_NUMERIC_FORWARD_DECLARED 1
216 # endif
217 
218 // Feature test macro for parallel algorithms
219 # define __cpp_lib_parallel_algorithm 201703L
220 #endif // C++17
221 
222 #endif /* _GLIBCXX_NUMERIC */
enable_if< ::__array_traits< _Tp, _Nm >::_Is_swappable::value >::type noexcept(noexcept(__one.swap(__two)))
swap
Definition: array:295
Parallel STL function calls corresponding to stl_numeric.h. The functions defined here mainly do case...
constexpr common_type_t< _Mn, _Nn > __lcm(_Mn __m, _Nn __n)
Least common multiple.
Definition: numeric:113