libstdc++
numeric
Go to the documentation of this file.
1 // <numeric> -*- C++ -*-
2 
3 // Copyright (C) 2001-2017 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 namespace __detail
83 {
84 _GLIBCXX_BEGIN_NAMESPACE_VERSION
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 
121 _GLIBCXX_END_NAMESPACE_VERSION
122 }
123 
124 _GLIBCXX_BEGIN_NAMESPACE_VERSION
125 
126 #if __cplusplus > 201402L
127 
128 #define __cpp_lib_gcd 201606
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<_Mn>::value, "gcd arguments are integers");
135  static_assert(is_integral<_Nn>::value, "gcd arguments are integers");
136  static_assert(!is_same<_Mn, bool>::value, "gcd arguments are not bools");
137  static_assert(!is_same<_Nn, bool>::value, "gcd arguments are not bools");
138  return __detail::__gcd(__m, __n);
139  }
140 
141 #define __cpp_lib_lcm 201606
142  /// Least common multiple
143  template<typename _Mn, typename _Nn>
144  constexpr common_type_t<_Mn, _Nn>
145  lcm(_Mn __m, _Nn __n)
146  {
147  static_assert(is_integral<_Mn>::value, "lcm arguments are integers");
148  static_assert(is_integral<_Nn>::value, "lcm arguments are integers");
149  static_assert(!is_same<_Mn, bool>::value, "lcm arguments are not bools");
150  static_assert(!is_same<_Nn, bool>::value, "lcm arguments are not bools");
151  return __detail::__lcm(__m, __n);
152  }
153 
154 #endif // C++17
155 
156 _GLIBCXX_END_NAMESPACE_VERSION
157 } // namespace std
158 
159 #endif // C++14
160 
161 
162 #endif /* _GLIBCXX_NUMERIC */
ISO C++ entities toplevel namespace is std.
is_integral
Definition: type_traits:328
constexpr common_type_t< _Mn, _Nn > __lcm(_Mn __m, _Nn __n)
Least common multiple.
Definition: numeric:113
Parallel STL function calls corresponding to stl_numeric.h. The functions defined here mainly do case...