[rand.dist.bern.bin]. The evaluation function for this binomial distribution is hopefully just a placeholder. It is using the simplest and slowest method for computing the distribution and needs to be upgraded.

llvm-svn: 103524
This commit is contained in:
Howard Hinnant 2010-05-11 23:26:59 +00:00
parent e476fa0b8e
commit deb23ecdf9
5 changed files with 168 additions and 13 deletions

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@ -642,5 +642,3 @@ __split_buffer<_Tp, _Allocator>::emplace_back(_Args&&... __args)
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_SPLIT_BUFFER
// hh 080222 Created

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@ -3820,5 +3820,3 @@ void* align(size_t, size_t, void*&, size_t&);
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_MEMORY
// hh 060228 Created

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@ -608,7 +608,62 @@ public:
};
template<class IntType = int>
class binomial_distribution;
class binomial_distribution
{
public:
// types
typedef IntType result_type;
class param_type
{
public:
typedef binomial_distribution distribution_type;
explicit param_type(IntType t = 1, double p = 0.5);
IntType t() const;
double p() const;
friend bool operator==(const param_type& x, const param_type& y);
friend bool operator!=(const param_type& x, const param_type& y);
};
// constructors and reset functions
explicit binomial_distribution(IntType t = 1, double p = 0.5);
explicit binomial_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
IntType t() const;
double p() const;
param_type param() const;
void param(const param_type& parm);
result_type min() const;
result_type max() const;
friend bool operator==(const binomial_distribution& x,
const binomial_distribution& y);
friend bool operator!=(const binomial_distribution& x,
const binomial_distribution& y);
template <class charT, class traits>
friend
basic_ostream<charT, traits>&
operator<<(basic_ostream<charT, traits>& os,
const binomial_distribution& x);
template <class charT, class traits>
friend
basic_istream<charT, traits>&
operator>>(basic_istream<charT, traits>& is,
binomial_distribution& x);
};
template<class IntType = int>
class geometric_distribution;
@ -2797,11 +2852,7 @@ public:
// 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)
{
return _STD::generate_canonical<double, numeric_limits<double>::digits>(__g)
< __p.p();
}
template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
// property functions
double p() const {return __p_.p();}
@ -2820,6 +2871,14 @@ public:
{return !(__x == __y);}
};
template<class _URNG>
inline
bernoulli_distribution::result_type
bernoulli_distribution::operator()(_URNG& __g, const param_type& __p)
{
return (__g() - __g.min()) < __p.p() * (__g.max() - __g.min() + 1.);
}
template <class _CharT, class _Traits>
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os, const bernoulli_distribution& __x)
@ -2846,6 +2905,108 @@ operator>>(basic_istream<_CharT, _Traits>& __is, bernoulli_distribution& __x)
return __is;
}
template<class _IntType = int>
class binomial_distribution
{
public:
// types
typedef _IntType result_type;
class param_type
{
result_type __t_;
double __p_;
public:
typedef binomial_distribution distribution_type;
explicit param_type(result_type __t = 1, double __p = 0.5)
: __t_(__t), __p_(__p) {}
result_type t() const {return __t_;}
double p() const {return __p_;}
friend bool operator==(const param_type& __x, const param_type& __y)
{return __x.__t_ == __y.__t_ && __x.__p_ == __y.__p_;}
friend bool operator!=(const param_type& __x, const param_type& __y)
{return !(__x == __y);}
};
private:
param_type __p_;
public:
// constructors and reset functions
explicit binomial_distribution(result_type __t = 1, double __p = 0.5)
: __p_(param_type(__t, __p)) {}
explicit binomial_distribution(const param_type& __p) : __p_(__p) {}
void 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 t() const {return __p_.t();}
double p() const {return __p_.p();}
param_type param() const {return __p_;}
void param(const param_type& __p) {__p_ = __p;}
result_type min() const {return 0;}
result_type max() const {return t();}
friend bool operator==(const binomial_distribution& __x,
const binomial_distribution& __y)
{return __x.__p_ == __y.__p_;}
friend bool operator!=(const binomial_distribution& __x,
const binomial_distribution& __y)
{return !(__x == __y);}
};
template<class _IntType>
template<class _URNG>
_IntType
binomial_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
{
bernoulli_distribution __bd(__p.p());
_IntType __r = 0;
_IntType __t = __p.t();
for (_IntType __i = 0; __i < __t; ++__i)
__r += __bd(__g);
return __r;
}
template <class _CharT, class _Traits, class _IntType>
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
const binomial_distribution<_IntType>& __x)
{
__save_flags<_CharT, _Traits> _(__os);
__os.flags(ios_base::dec | ios_base::left);
_CharT __sp = __os.widen(' ');
__os.fill(__sp);
return __os << __x.t() << __sp << __x.p();
}
template <class _CharT, class _Traits, class _IntType>
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is,
binomial_distribution<_IntType>& __x)
{
typedef binomial_distribution<_IntType> _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 __t;
double __p;
__is >> __t >> __p;
if (!__is.fail())
__x.param(param_type(__t, __p));
return __is;
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_RANDOM

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@ -3539,5 +3539,3 @@ extern template
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STRING
// hh 060525 Created

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@ -19,7 +19,7 @@
int main()
{
{
typedef std::uniform_int_distribution<> D;
typedef std::bernoulli_distribution D;
typedef std::minstd_rand0 G;
G g;
D d(.75);