[rand.dist.norm.t] git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@104052 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/random b/include/random index f1ae33b..6a3dcce 100644 --- a/include/random +++ b/include/random
@@ -1305,7 +1305,7 @@ class param_type { public: - typedef result_type distribution_type; + typedef fisher_f_distribution distribution_type; explicit param_type(result_type m = 1, result_type n = 1); @@ -1354,7 +1354,60 @@ }; template<class RealType = double> - class student_t_distribution; +class student_t_distribution +{ +public: + // types + typedef RealType result_type; + + class param_type + { + public: + typedef student_t_distribution distribution_type; + + explicit param_type(result_type n = 1); + + result_type n() const; + + friend bool operator==(const param_type& x, const param_type& y); + friend bool operator!=(const param_type& x, const param_type& y); + }; + + // constructor and reset functions + explicit student_t_distribution(result_type n = 1); + explicit student_t_distribution(const param_type& parm); + void reset(); + + // generating functions + template<class URNG> result_type operator()(URNG& g); + template<class URNG> result_type operator()(URNG& g, const param_type& parm); + + // property functions + result_type n() const; + + param_type param() const; + void param(const param_type& parm); + + result_type min() const; + result_type max() const; + + friend bool operator==(const student_t_distribution& x, + const student_t_distribution& y); + friend bool operator!=(const student_t_distribution& x, + const student_t_distribution& y); + + template <class charT, class traits> + friend + basic_ostream<charT, traits>& + operator<<(basic_ostream<charT, traits>& os, + const student_t_distribution& x); + + template <class charT, class traits> + friend + basic_istream<charT, traits>& + operator>>(basic_istream<charT, traits>& is, + student_t_distribution& x); +}; template<class IntType = int> class discrete_distribution; @@ -5123,6 +5176,100 @@ return __is; } +template<class _RealType = double> +class student_t_distribution +{ +public: + // types + typedef _RealType result_type; + + class param_type + { + result_type __n_; + public: + typedef student_t_distribution distribution_type; + + explicit param_type(result_type __n = 1) : __n_(__n) {} + + result_type n() const {return __n_;} + + friend bool operator==(const param_type& __x, const param_type& __y) + {return __x.__n_ == __y.__n_;} + friend bool operator!=(const param_type& __x, const param_type& __y) + {return !(__x == __y);} + }; + +private: + param_type __p_; + normal_distribution<result_type> __nd_; + +public: + // constructor and reset functions + explicit student_t_distribution(result_type __n = 1) + : __p_(param_type(__n)) {} + explicit student_t_distribution(const param_type& __p) + : __p_(__p) {} + void reset() {__nd_.reset();} + + // generating functions + template<class _URNG> result_type operator()(_URNG& __g) + {return (*this)(__g, __p_);} + template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p); + + // property functions + result_type n() const {return __p_.n();} + + param_type param() const {return __p_;} + void param(const param_type& __p) {return __p_ = __p;} + + result_type min() const {return -numeric_limits<result_type>::infinity();} + result_type max() const {return numeric_limits<result_type>::infinity();} + + friend bool operator==(const student_t_distribution& __x, + const student_t_distribution& __y) + {return __x.__p_ == __y.__p_;} + friend bool operator!=(const student_t_distribution& __x, + const student_t_distribution& __y) + {return !(__x == __y);} +}; + +template <class _RealType> +template<class _URNG> +_RealType +student_t_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) +{ + gamma_distribution<result_type> __gd(__p.n() * .5, 2); + return __nd_(__g) * _STD::sqrt(__p.n()/__gd(__g)); +} + +template <class _CharT, class _Traits, class _RT> +basic_ostream<_CharT, _Traits>& +operator<<(basic_ostream<_CharT, _Traits>& __os, + const student_t_distribution<_RT>& __x) +{ + __save_flags<_CharT, _Traits> _(__os); + __os.flags(ios_base::dec | ios_base::left); + __os << __x.n(); + return __os; +} + +template <class _CharT, class _Traits, class _RT> +basic_istream<_CharT, _Traits>& +operator>>(basic_istream<_CharT, _Traits>& __is, + student_t_distribution<_RT>& __x) +{ + typedef student_t_distribution<_RT> _Eng; + typedef typename _Eng::result_type result_type; + typedef typename _Eng::param_type param_type; + __save_flags<_CharT, _Traits> _(__is); + __is.flags(ios_base::dec | ios_base::skipws); + result_type __n; + __is >> __n; + if (!__is.fail()) + __x.param(param_type(__n)); + return __is; +} + _LIBCPP_END_NAMESPACE_STD #endif // _LIBCPP_RANDOM