lognormal_distribution.h 4.5 KB

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  1. //===----------------------------------------------------------------------===//
  2. //
  3. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  4. // See https://llvm.org/LICENSE.txt for license information.
  5. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  6. //
  7. //===----------------------------------------------------------------------===//
  8. #ifndef _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H
  9. #define _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H
  10. #include <__config>
  11. #include <__random/is_valid.h>
  12. #include <__random/normal_distribution.h>
  13. #include <cmath>
  14. #include <iosfwd>
  15. #include <limits>
  16. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  17. # pragma GCC system_header
  18. #endif
  19. _LIBCPP_PUSH_MACROS
  20. #include <__undef_macros>
  21. _LIBCPP_BEGIN_NAMESPACE_STD
  22. template <class _RealType = double>
  23. class _LIBCPP_TEMPLATE_VIS lognormal_distribution {
  24. static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,
  25. "RealType must be a supported floating-point type");
  26. public:
  27. // types
  28. typedef _RealType result_type;
  29. class _LIBCPP_TEMPLATE_VIS param_type {
  30. result_type __m_;
  31. result_type __s_;
  32. public:
  33. typedef lognormal_distribution distribution_type;
  34. _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __m = 0, result_type __s = 1) : __m_(__m), __s_(__s) {}
  35. _LIBCPP_HIDE_FROM_ABI result_type m() const { return __m_; }
  36. _LIBCPP_HIDE_FROM_ABI result_type s() const { return __s_; }
  37. friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
  38. return __x.__m_ == __y.__m_ && __x.__s_ == __y.__s_;
  39. }
  40. friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
  41. };
  42. private:
  43. normal_distribution<result_type> __nd_;
  44. public:
  45. // constructor and reset functions
  46. #ifndef _LIBCPP_CXX03_LANG
  47. _LIBCPP_HIDE_FROM_ABI lognormal_distribution() : lognormal_distribution(0) {}
  48. _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(result_type __m, result_type __s = 1) : __nd_(__m, __s) {}
  49. #else
  50. _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(result_type __m = 0, result_type __s = 1) : __nd_(__m, __s) {}
  51. #endif
  52. _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(const param_type& __p) : __nd_(__p.m(), __p.s()) {}
  53. _LIBCPP_HIDE_FROM_ABI void reset() { __nd_.reset(); }
  54. // generating functions
  55. template <class _URNG>
  56. _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
  57. return std::exp(__nd_(__g));
  58. }
  59. template <class _URNG>
  60. _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p) {
  61. typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
  62. return std::exp(__nd_(__g, __pn));
  63. }
  64. // property functions
  65. _LIBCPP_HIDE_FROM_ABI result_type m() const { return __nd_.mean(); }
  66. _LIBCPP_HIDE_FROM_ABI result_type s() const { return __nd_.stddev(); }
  67. _LIBCPP_HIDE_FROM_ABI param_type param() const { return param_type(__nd_.mean(), __nd_.stddev()); }
  68. _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) {
  69. typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
  70. __nd_.param(__pn);
  71. }
  72. _LIBCPP_HIDE_FROM_ABI result_type min() const { return 0; }
  73. _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); }
  74. friend _LIBCPP_HIDE_FROM_ABI bool operator==(const lognormal_distribution& __x, const lognormal_distribution& __y) {
  75. return __x.__nd_ == __y.__nd_;
  76. }
  77. friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const lognormal_distribution& __x, const lognormal_distribution& __y) {
  78. return !(__x == __y);
  79. }
  80. template <class _CharT, class _Traits, class _RT>
  81. friend basic_ostream<_CharT, _Traits>&
  82. operator<<(basic_ostream<_CharT, _Traits>& __os, const lognormal_distribution<_RT>& __x);
  83. template <class _CharT, class _Traits, class _RT>
  84. friend basic_istream<_CharT, _Traits>&
  85. operator>>(basic_istream<_CharT, _Traits>& __is, lognormal_distribution<_RT>& __x);
  86. };
  87. template <class _CharT, class _Traits, class _RT>
  88. inline _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
  89. operator<<(basic_ostream<_CharT, _Traits>& __os, const lognormal_distribution<_RT>& __x) {
  90. return __os << __x.__nd_;
  91. }
  92. template <class _CharT, class _Traits, class _RT>
  93. inline _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
  94. operator>>(basic_istream<_CharT, _Traits>& __is, lognormal_distribution<_RT>& __x) {
  95. return __is >> __x.__nd_;
  96. }
  97. _LIBCPP_END_NAMESPACE_STD
  98. _LIBCPP_POP_MACROS
  99. #endif // _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H