diff options
| author | paolo <paolo@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-03-25 10:06:33 +0000 |
|---|---|---|
| committer | paolo <paolo@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-03-25 10:06:33 +0000 |
| commit | b74d57a52001bad39e29f0a4efc41150d53e0bbd (patch) | |
| tree | c2c00d3744d6db99bffcbbfba5d53c4e3559288b /libstdc++-v3/include/bits/random.tcc | |
| parent | 5c55078237e2a812e69d6b76ca8ac82e4b2f3819 (diff) | |
| download | gcc-b74d57a52001bad39e29f0a4efc41150d53e0bbd.tar.gz | |
2011-03-25 Paolo Carlini <paolo.carlini@oracle.com>
* include/bits/random.h (negative_binomial_distribution<>::
negative_binomial_distribution(_IntType, double),
negative_binomial_distribution<>::
negative_binomial_distribution(const param_type&)): Tweak
construction of _M_gd.
* include/bits/random.tcc (negative_binomial_distribution<>::
operator()): Adjust.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@171443 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'libstdc++-v3/include/bits/random.tcc')
| -rw-r--r-- | libstdc++-v3/include/bits/random.tcc | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/libstdc++-v3/include/bits/random.tcc b/libstdc++-v3/include/bits/random.tcc index 0bbc9fd400d..01ee5824cd9 100644 --- a/libstdc++-v3/include/bits/random.tcc +++ b/libstdc++-v3/include/bits/random.tcc @@ -1075,7 +1075,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return __is; } - // This is Leger's algorithm. + // This is Leger's algorithm, also in Devroye, Ch. X, Example 1.5. template<typename _IntType> template<typename _UniformRandomNumberGenerator> typename negative_binomial_distribution<_IntType>::result_type @@ -1085,8 +1085,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION const double __y = _M_gd(__urng); // XXX Is the constructor too slow? - std::poisson_distribution<result_type> __poisson(__y * (1.0 - p()) - / p()); + std::poisson_distribution<result_type> __poisson(__y); return __poisson(__urng); } @@ -1100,10 +1099,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION typedef typename std::gamma_distribution<result_type>::param_type param_type; - const double __y = _M_gd(__urng, param_type(__p.k(), 1.0)); + const double __y = + _M_gd(__urng, param_type(__p.k(), (1.0 - __p.p()) / __p.p())); - std::poisson_distribution<result_type> __poisson(__y * (1.0 - __p.p()) - / __p.p() ); + std::poisson_distribution<result_type> __poisson(__y); return __poisson(__urng); } |