include/__random/lognormal_distribution.h

//===----------------------------------------------------------------------===//
//
// 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_LOGNORMAL_DISTRIBUTION_H
#define _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H

#include <__config>
#include <__random/normal_distribution.h>
#include <cmath>
#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 _RealType = double>
class _LIBCPP_TEMPLATE_VIS lognormal_distribution
{
public:
    // types
    typedef _RealType result_type;

    class _LIBCPP_TEMPLATE_VIS param_type
    {
        normal_distribution<result_type> __nd_;
    public:
        typedef lognormal_distribution distribution_type;

        _LIBCPP_INLINE_VISIBILITY
        explicit param_type(result_type __m = 0, result_type __s = 1)
            : __nd_(__m, __s) {}

        _LIBCPP_INLINE_VISIBILITY
        result_type m() const {return __nd_.mean();}
        _LIBCPP_INLINE_VISIBILITY
        result_type s() const {return __nd_.stddev();}

        friend _LIBCPP_INLINE_VISIBILITY
            bool operator==(const param_type& __x, const param_type& __y)
            {return __x.__nd_ == __y.__nd_;}
        friend _LIBCPP_INLINE_VISIBILITY
            bool operator!=(const param_type& __x, const param_type& __y)
            {return !(__x == __y);}
        friend class lognormal_distribution;

        template <class _CharT, class _Traits, class _RT>
        friend
        basic_ostream<_CharT, _Traits>&
        operator<<(basic_ostream<_CharT, _Traits>& __os,
                   const lognormal_distribution<_RT>& __x);

        template <class _CharT, class _Traits, class _RT>
        friend
        basic_istream<_CharT, _Traits>&
        operator>>(basic_istream<_CharT, _Traits>& __is,
                   lognormal_distribution<_RT>& __x);
    };

private:
    param_type __p_;

public:
    // constructor and reset functions
#ifndef _LIBCPP_CXX03_LANG
    _LIBCPP_INLINE_VISIBILITY
    lognormal_distribution() : lognormal_distribution(0) {}
    _LIBCPP_INLINE_VISIBILITY
    explicit lognormal_distribution(result_type __m, result_type __s = 1)
        : __p_(param_type(__m, __s)) {}
#else
    _LIBCPP_INLINE_VISIBILITY
    explicit lognormal_distribution(result_type __m = 0,
                                    result_type __s = 1)
        : __p_(param_type(__m, __s)) {}
#endif
    _LIBCPP_INLINE_VISIBILITY
    explicit lognormal_distribution(const param_type& __p)
        : __p_(__p) {}
    _LIBCPP_INLINE_VISIBILITY
    void reset() {__p_.__nd_.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 _VSTD::exp(const_cast<normal_distribution<result_type>&>(__p.__nd_)(__g));}

    // property functions
    _LIBCPP_INLINE_VISIBILITY
    result_type m() const {return __p_.m();}
    _LIBCPP_INLINE_VISIBILITY
    result_type s() const {return __p_.s();}

    _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>::infinity();}

    friend _LIBCPP_INLINE_VISIBILITY
        bool operator==(const lognormal_distribution& __x,
                        const lognormal_distribution& __y)
        {return __x.__p_ == __y.__p_;}
    friend _LIBCPP_INLINE_VISIBILITY
        bool operator!=(const lognormal_distribution& __x,
                        const lognormal_distribution& __y)
        {return !(__x == __y);}

    template <class _CharT, class _Traits, class _RT>
    friend
    basic_ostream<_CharT, _Traits>&
    operator<<(basic_ostream<_CharT, _Traits>& __os,
               const lognormal_distribution<_RT>& __x);

    template <class _CharT, class _Traits, class _RT>
    friend
    basic_istream<_CharT, _Traits>&
    operator>>(basic_istream<_CharT, _Traits>& __is,
               lognormal_distribution<_RT>& __x);
};

template <class _CharT, class _Traits, class _RT>
inline _LIBCPP_INLINE_VISIBILITY
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
           const lognormal_distribution<_RT>& __x)
{
    return __os << __x.__p_.__nd_;
}

template <class _CharT, class _Traits, class _RT>
inline _LIBCPP_INLINE_VISIBILITY
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is,
           lognormal_distribution<_RT>& __x)
{
    return __is >> __x.__p_.__nd_;
}

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H