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| author | Andrey Zholos <aaz@althenia.net> | 2011-03-14 17:57:48 +0000 |
|---|---|---|
| committer | Paolo Carlini <paolo@gcc.gnu.org> | 2011-03-14 17:57:48 +0000 |
| commit | d8d4db3345ec3271a5edf4bd84e999662cd8e2e2 (patch) | |
| tree | 252af3acb8afb7f38157c3d59aadf4acfdef3cd4 /libstdc++-v3 | |
| parent | 7edc478cef220dd4fa0dbe3a50c1030abac83ec1 (diff) | |
| download | gcc-d8d4db3345ec3271a5edf4bd84e999662cd8e2e2.tar.gz | |
re PR libstdc++/48114 ([C++0x] binomial_distribution incorrect for p > .5 and geometric_distribution wrongly implements the TR1 definition)
2011-03-14 Andrey Zholos <aaz@althenia.net>
PR libstdc++/48114
* include/bits/random.h (geometric_distribution): Correct formula
in comment, per C++0x.
(geometric_distribution<>::param_type::param_type(double)): Fix check.
(geometric_distribution<>::param_type::_M_initialize):
Store log(1 - p).
* include/bits/random.tcc (geometric_distribution<>::operator()):
Fix computation.
(binomial_distribution<>::operator()): Likewise.
From-SVN: r170946
Diffstat (limited to 'libstdc++-v3')
| -rw-r--r-- | libstdc++-v3/ChangeLog | 12 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/random.h | 12 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/random.tcc | 4 |
3 files changed, 20 insertions, 8 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 6c3f1d34cda..ef93431bf09 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,15 @@ +2011-03-14 Andrey Zholos <aaz@althenia.net> + + PR libstdc++/48114 + * include/bits/random.h (geometric_distribution): Correct formula + in comment, per C++0x. + (geometric_distribution<>::param_type::param_type(double)): Fix check. + (geometric_distribution<>::param_type::_M_initialize): + Store log(1 - p). + * include/bits/random.tcc (geometric_distribution<>::operator()): + Fix computation. + (binomial_distribution<>::operator()): Likewise. + 2011-03-09 Paolo Carlini <paolo.carlini@oracle.com> * testsuite/util/testsuite_rvalref.h: Minor tweaks. diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h index 5c406a648c3..26cec8a885e 100644 --- a/libstdc++-v3/include/bits/random.h +++ b/libstdc++-v3/include/bits/random.h @@ -1,6 +1,6 @@ // random number generation -*- C++ -*- -// Copyright (C) 2009, 2010 Free Software Foundation, Inc. +// Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the @@ -3589,7 +3589,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION * @brief A discrete geometric random number distribution. * * The formula for the geometric probability density function is - * @f$p(i|p) = (1 - p)p^{i-1}@f$ where @f$p@f$ is the parameter of the + * @f$p(i|p) = p(1 - p)^{i}@f$ where @f$p@f$ is the parameter of the * distribution. */ template<typename _IntType = int> @@ -3611,8 +3611,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION param_type(double __p = 0.5) : _M_p(__p) { - _GLIBCXX_DEBUG_ASSERT((_M_p >= 0.0) - && (_M_p <= 1.0)); + _GLIBCXX_DEBUG_ASSERT((_M_p > 0.0) + && (_M_p < 1.0)); _M_initialize(); } @@ -3627,11 +3627,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION private: void _M_initialize() - { _M_log_p = std::log(_M_p); } + { _M_log_1_p = std::log(1.0 - _M_p); } double _M_p; - double _M_log_p; + double _M_log_1_p; }; // constructors and member function diff --git a/libstdc++-v3/include/bits/random.tcc b/libstdc++-v3/include/bits/random.tcc index 20f7667e298..4b17e914e56 100644 --- a/libstdc++-v3/include/bits/random.tcc +++ b/libstdc++-v3/include/bits/random.tcc @@ -1025,7 +1025,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION double __cand; do - __cand = std::ceil(std::log(__aurng()) / __param._M_log_p); + __cand = std::floor(std::log(__aurng()) / __param._M_log_1_p); while (__cand >= __thr); return result_type(__cand + __naf); @@ -1434,7 +1434,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { result_type __ret; const _IntType __t = __param.t(); - const _IntType __p = __param.p(); + const double __p = __param.p(); const double __p12 = __p <= 0.5 ? __p : 1.0 - __p; __detail::_Adaptor<_UniformRandomNumberGenerator, double> __aurng(__urng); |