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random (gamma_distribution<>::_M_initialize, [...]): Add.

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2006-08-20  Paolo Carlini  <pcarlini@suse.de>

	* include/tr1/random (gamma_distribution<>::_M_initialize,
	gamma_distribution<>::_M_l_d): Add.
	(gamma_distribution<>::gamma_distribution(const result_type&),
	operator>>(std::basic_istream<>&, gamma_distribution&)): Use it.
	include/tr1/random.tcc (gamma_distribution<>::_M_initialize):
	Define.
	(gamma_distribution<>::operator()): Adjust.

	* include/tr1/random (geometric_distribution<>::_M_initialize): Add.
	(geometric_distribution<>::geometric_distribution(const _RealType&),
	operator>>(std::basic_istream<>&, geometric_distribution&)): Use it.

From-SVN: r116273
This commit is contained in:
Paolo Carlini 2006-08-20 16:05:05 +00:00 committed by Paolo Carlini
parent ffcba5714a
commit 96ddac7425
3 changed files with 64 additions and 23 deletions
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14
libstdc++-v3/ChangeLog
View File

@ -1,3 +1,17 @@
2006-08-20 Paolo Carlini <pcarlini@suse.de>
* include/tr1/random (gamma_distribution<>::_M_initialize,
gamma_distribution<>::_M_l_d): Add.
(gamma_distribution<>::gamma_distribution(const result_type&),
operator>>(std::basic_istream<>&, gamma_distribution&)): Use it.
include/tr1/random.tcc (gamma_distribution<>::_M_initialize):
Define.
(gamma_distribution<>::operator()): Adjust.
* include/tr1/random (geometric_distribution<>::_M_initialize): Add.
(geometric_distribution<>::geometric_distribution(const _RealType&),
operator>>(std::basic_istream<>&, geometric_distribution&)): Use it.
2006-08-18 Paolo Carlini <pcarlini@suse.de>
* include/tr1/random (class binomial_distribution<>): Add.

25
libstdc++-v3/include/tr1/random
View File

@ -1588,9 +1588,10 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
// constructors and member function
explicit
geometric_distribution(const _RealType& __p = _RealType(0.5))
: _M_p(__p), _M_log_p(std::log(__p))
: _M_p(__p)
{
_GLIBCXX_DEBUG_ASSERT((_M_p > 0.0) && (_M_p < 1.0));
_M_initialize();
}
/**
@ -1639,11 +1640,15 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
geometric_distribution& __x)
{
__is >> __x._M_p;
__x._M_log_p = std::log(__x._M_p);
__x._M_initialize();
return __is;
}
private:
void
_M_initialize()
{ _M_log_p = std::log(_M_p); }
_RealType _M_p;
_RealType _M_log_p;
};
@ -1746,8 +1751,7 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
_RealType _M_mean;
// _M_lm_thr hosts either log(mean) or the threshold of the simple
// method.
// Hosts either log(mean) or the threshold of the simple method.
_RealType _M_lm_thr;
#if _GLIBCXX_USE_C99_MATH_TR1
_RealType _M_lfm, _M_sm, _M_d, _M_scx, _M_1cx, _M_c2b, _M_cb;
@ -2204,6 +2208,7 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
: _M_alpha(__alpha_val)
{
_GLIBCXX_DEBUG_ASSERT(_M_alpha > 0);
_M_initialize();
}
/**
@ -2251,10 +2256,20 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
friend std::basic_istream<_CharT, _Traits>&
operator>>(std::basic_istream<_CharT, _Traits>& __is,
gamma_distribution& __x)
{ return __is >> __x._M_alpha; }
{
__is >> __x._M_alpha;
__x._M_initialize();
return __is;
}
private:
void
_M_initialize();
result_type _M_alpha;
// Hosts either lambda of GB or d of modified Vaduva's.
result_type _M_l_d;
};
/* @} */ // group tr1_random_distributions_continuous

48
libstdc++-v3/include/tr1/random.tcc
View File

@ -1106,11 +1106,10 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
/**
* Classic Box-Muller method.
* Polar method due to Marsaglia.
*
* Reference:
* Box, G. E. P. and Muller, M. E. "A Note on the Generation of
* Random Normal Deviates." Ann. Math. Stat. 29, 610-611, 1958.
* Devroye, L. "Non-Uniform Random Variates Generation." Springer-Verlag,
* New York, 1986, Ch. V, Sect. 4.4.
*/
template<typename _RealType>
template<class _UniformRandomNumberGenerator>
@ -1189,6 +1188,18 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
}
template<typename _RealType>
void
gamma_distribution<_RealType>::
_M_initialize()
{
if (_M_alpha >= 1)
_M_l_d = std::sqrt(2 * _M_alpha - 1);
else
_M_l_d = (std::pow(_M_alpha, _M_alpha / (1 - _M_alpha))
* (1 - _M_alpha));
}
/**
* Cheng's rejection algorithm GB for alpha >= 1 and a modification
* of Vaduva's rejection from Weibull algorithm due to Devroye for
@ -1213,19 +1224,18 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
{
result_type __x;
bool __reject;
if (_M_alpha >= 1)
{
// alpha - log(4)
const result_type __b = _M_alpha
- result_type(1.3862943611198906188344642429163531L);
const result_type __l = std::sqrt(2 * _M_alpha - 1);
const result_type __c = _M_alpha + __l;
const result_type __1l = 1 / __l;
const result_type __c = _M_alpha + _M_l_d;
const result_type __1l = 1 / _M_l_d;
// 1 + log(9 / 2)
const result_type __k = 2.5040773967762740733732583523868748L;
result_type __z, __r;
do
{
const result_type __u = __urng();
@ -1234,27 +1244,29 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
const result_type __y = __1l * std::log(__v / (1 - __v));
__x = _M_alpha * std::exp(__y);
__z = __u * __v * __v;
__r = __b + __c * __y - __x;
const result_type __z = __u * __v * __v;
const result_type __r = __b + __c * __y - __x;
__reject = __r < result_type(4.5) * __z - __k;
if (__reject)
__reject = __r < std::log(__z);
}
while (__r < result_type(4.5) * __z - __k
&& __r < std::log(__z));
while (__reject);
}
else
{
const result_type __c = 1 / _M_alpha;
const result_type __d =
std::pow(_M_alpha, _M_alpha / (1 - _M_alpha)) * (1 - _M_alpha);
result_type __z, __e;
do
{
__z = -std::log(__urng());
__e = -std::log(__urng());
const result_type __z = -std::log(__urng());
const result_type __e = -std::log(__urng());
__x = std::pow(__z, __c);
__reject = __z + __e < _M_l_d + __x;
}
while (__z + __e < __d + __x);
while (__reject);
}
return __x;