llvm-project/libcxx/include/__random/geometric_distribution.h

142 lines
4.2 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H
#define _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H
#include <__config>
#include <__random/negative_binomial_distribution.h>
#include <iosfwd>
#include <limits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
template<class _IntType = int>
class _LIBCPP_TEMPLATE_VIS geometric_distribution
{
public:
// types
typedef _IntType result_type;
class _LIBCPP_TEMPLATE_VIS param_type
{
double __p_;
public:
typedef geometric_distribution distribution_type;
_LIBCPP_INLINE_VISIBILITY
explicit param_type(double __p = 0.5) : __p_(__p) {}
_LIBCPP_INLINE_VISIBILITY
double p() const {return __p_;}
friend _LIBCPP_INLINE_VISIBILITY
bool operator==(const param_type& __x, const param_type& __y)
{return __x.__p_ == __y.__p_;}
friend _LIBCPP_INLINE_VISIBILITY
bool operator!=(const param_type& __x, const param_type& __y)
{return !(__x == __y);}
};
private:
param_type __p_;
public:
// constructors and reset functions
#ifndef _LIBCPP_CXX03_LANG
_LIBCPP_INLINE_VISIBILITY
geometric_distribution() : geometric_distribution(0.5) {}
_LIBCPP_INLINE_VISIBILITY
explicit geometric_distribution(double __p)
: __p_(__p) {}
#else
_LIBCPP_INLINE_VISIBILITY
explicit geometric_distribution(double __p = 0.5)
: __p_(__p) {}
#endif
_LIBCPP_INLINE_VISIBILITY
explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
_LIBCPP_INLINE_VISIBILITY
void reset() {}
// generating functions
template<class _URNG>
_LIBCPP_INLINE_VISIBILITY
result_type operator()(_URNG& __g)
{return (*this)(__g, __p_);}
template<class _URNG>
_LIBCPP_INLINE_VISIBILITY
result_type operator()(_URNG& __g, const param_type& __p)
{return negative_binomial_distribution<result_type>(1, __p.p())(__g);}
// property functions
_LIBCPP_INLINE_VISIBILITY
double p() const {return __p_.p();}
_LIBCPP_INLINE_VISIBILITY
param_type param() const {return __p_;}
_LIBCPP_INLINE_VISIBILITY
void param(const param_type& __p) {__p_ = __p;}
_LIBCPP_INLINE_VISIBILITY
result_type min() const {return 0;}
_LIBCPP_INLINE_VISIBILITY
result_type max() const {return numeric_limits<result_type>::max();}
friend _LIBCPP_INLINE_VISIBILITY
bool operator==(const geometric_distribution& __x,
const geometric_distribution& __y)
{return __x.__p_ == __y.__p_;}
friend _LIBCPP_INLINE_VISIBILITY
bool operator!=(const geometric_distribution& __x,
const geometric_distribution& __y)
{return !(__x == __y);}
};
template <class _CharT, class _Traits, class _IntType>
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
const geometric_distribution<_IntType>& __x)
{
__save_flags<_CharT, _Traits> __lx(__os);
typedef basic_ostream<_CharT, _Traits> _OStream;
__os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
_OStream::scientific);
return __os << __x.p();
}
template <class _CharT, class _Traits, class _IntType>
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is,
geometric_distribution<_IntType>& __x)
{
typedef geometric_distribution<_IntType> _Eng;
typedef typename _Eng::param_type param_type;
__save_flags<_CharT, _Traits> __lx(__is);
typedef basic_istream<_CharT, _Traits> _Istream;
__is.flags(_Istream::dec | _Istream::skipws);
double __p;
__is >> __p;
if (!__is.fail())
__x.param(param_type(__p));
return __is;
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H