diff options
Diffstat (limited to 'libstdc++-v3/include/tr1/random.tcc')
| -rw-r--r-- | libstdc++-v3/include/tr1/random.tcc | 42 |
1 files changed, 40 insertions, 2 deletions
diff --git a/libstdc++-v3/include/tr1/random.tcc b/libstdc++-v3/include/tr1/random.tcc index 8624f128f35..67d79edf69a 100644 --- a/libstdc++-v3/include/tr1/random.tcc +++ b/libstdc++-v3/include/tr1/random.tcc @@ -768,6 +768,28 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1) } + template<typename _IntType, typename _RealType> + template<class _UniformRandomNumberGenerator> + typename geometric_distribution<_IntType, _RealType>::result_type + geometric_distribution<_IntType, _RealType>:: + operator()(_UniformRandomNumberGenerator& __urng) + { + // About the epsilon thing see this thread: + // http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00971.html + const _RealType __naf = + (1 - std::numeric_limits<_RealType>::epsilon()) / 2; + // The largest _RealType convertible to _IntType. + const _RealType __thr = + std::numeric_limits<_IntType>::max() + __naf; + + _RealType __cand; + do + __cand = std::ceil(std::log(__urng()) / _M_log_p); + while (__cand >= __thr); + + return result_type(__cand + __naf); + } + template<typename _IntType, typename _RealType, typename _CharT, typename _Traits> std::basic_ostream<_CharT, _Traits>& @@ -841,6 +863,12 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1) { _RealType __x; + // See comments above... + const _RealType __naf = + (1 - std::numeric_limits<_RealType>::epsilon()) / 2; + const _RealType __thr = + std::numeric_limits<_IntType>::max() + __naf; + const _RealType __m = std::floor(_M_mean); // sqrt(pi / 2) const _RealType __spi_2 = 1.2533141373155002512078826424055226L; @@ -899,9 +927,11 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1) __reject = (__w - __e - __x * _M_lm_thr > _M_lfm - std::tr1::lgamma(__x + __m + 1)); + __reject |= __x + __m >= __thr; + } while (__reject); - return _IntType(__x + __m + 0.5); + return result_type(__x + __m + __naf); } else #endif @@ -1055,6 +1085,12 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1) { _RealType __x; + // See comments above... + const _RealType __naf = + (1 - std::numeric_limits<_RealType>::epsilon()) / 2; + const _RealType __thr = + std::numeric_limits<_IntType>::max() + __naf; + const _RealType __np = std::floor(_M_t * __p12); const _RealType __pa = __np / _M_t; @@ -1127,10 +1163,12 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1) + std::tr1::lgamma(_M_t - (__np + __x) + 1); __reject = __v > _M_lf - __lfx + __x * _M_lp1p; } + + __reject |= __x + __np >= __thr; } while (__reject); - __x += __np + 0.5; + __x += __np + __naf; const _IntType __z = _M_waiting(__urng, _M_t - _IntType(__x)); __ret = _IntType(__x) + __z; |