// random number generation (out of line) -*- 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
/** @file bits/random.tcc
* This is an internal header file, included by other library headers.
- * You should not attempt to use it directly.
+ * Do not attempt to use it directly. @headername{random}
*/
+#ifndef _RANDOM_TCC
+#define _RANDOM_TCC 1
+
#include <numeric> // std::accumulate and std::partial_sum
-namespace std
+namespace std _GLIBCXX_VISIBILITY(default)
{
/*
* (Further) implementation-space details.
*/
namespace __detail
{
+ _GLIBCXX_BEGIN_NAMESPACE_VERSION
+
// General case for x = (ax + c) mod m -- use Schrage's algorithm to
// avoid integer overflow.
//
{ return __a * __x + __c; }
};
- template<typename _InputIterator, typename _OutputIterator,
- typename _UnaryOperation>
- _OutputIterator
- __transform(_InputIterator __first, _InputIterator __last,
- _OutputIterator __result, _UnaryOperation __unary_op)
- {
- for (; __first != __last; ++__first, ++__result)
- *__result = __unary_op(*__first);
- return __result;
- }
+ template<typename _InputIterator, typename _OutputIterator,
+ typename _UnaryOperation>
+ _OutputIterator
+ __transform(_InputIterator __first, _InputIterator __last,
+ _OutputIterator __result, _UnaryOperation __unary_op)
+ {
+ for (; __first != __last; ++__first, ++__result)
+ *__result = __unary_op(*__first);
+ return __result;
+ }
+
+ _GLIBCXX_END_NAMESPACE_VERSION
} // namespace __detail
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
- const _UIntType
+ constexpr _UIntType
linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
- const _UIntType
+ constexpr _UIntType
linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
- const _UIntType
+ constexpr _UIntType
linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
- const _UIntType
+ constexpr _UIntType
linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
/**
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::word_size;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::state_size;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::shift_size;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::mask_bits;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const _UIntType
+ constexpr _UIntType
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::xor_mask;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::tempering_u;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const _UIntType
+ constexpr _UIntType
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::tempering_d;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::tempering_s;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const _UIntType
+ constexpr _UIntType
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::tempering_b;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::tempering_t;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const _UIntType
+ constexpr _UIntType
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::tempering_c;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const size_t
+ constexpr size_t
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::tempering_l;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const _UIntType
+ constexpr _UIntType
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::
initialization_multiplier;
_UIntType __a, size_t __u, _UIntType __d, size_t __s,
_UIntType __b, size_t __t, _UIntType __c, size_t __l,
_UIntType __f>
- const _UIntType
+ constexpr _UIntType
mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
__s, __b, __t, __c, __l, __f>::default_seed;
template<typename _UIntType, size_t __w, size_t __s, size_t __r>
- const size_t
+ constexpr size_t
subtract_with_carry_engine<_UIntType, __w, __s, __r>::word_size;
template<typename _UIntType, size_t __w, size_t __s, size_t __r>
- const size_t
+ constexpr size_t
subtract_with_carry_engine<_UIntType, __w, __s, __r>::short_lag;
template<typename _UIntType, size_t __w, size_t __s, size_t __r>
- const size_t
+ constexpr size_t
subtract_with_carry_engine<_UIntType, __w, __s, __r>::long_lag;
template<typename _UIntType, size_t __w, size_t __s, size_t __r>
- const _UIntType
+ constexpr _UIntType
subtract_with_carry_engine<_UIntType, __w, __s, __r>::default_seed;
template<typename _UIntType, size_t __w, size_t __s, size_t __r>
template<typename _RandomNumberEngine, size_t __p, size_t __r>
- const size_t
+ constexpr size_t
discard_block_engine<_RandomNumberEngine, __p, __r>::block_size;
template<typename _RandomNumberEngine, size_t __p, size_t __r>
- const size_t
+ constexpr size_t
discard_block_engine<_RandomNumberEngine, __p, __r>::used_block;
template<typename _RandomNumberEngine, size_t __p, size_t __r>
template<typename _RandomNumberEngine, size_t __k>
- const size_t
+ constexpr size_t
shuffle_order_engine<_RandomNumberEngine, __k>::table_size;
template<typename _RandomNumberEngine, size_t __k>
operator()(_UniformRandomNumberGenerator& __urng,
const param_type& __param)
{
- // XXX Must be fixed to work well for *arbitrary* __urng.max(),
- // __urng.min(), __param.b(), __param.a(). Currently works fine only
- // in the most common case __urng.max() - __urng.min() >=
- // __param.b() - __param.a(), with __urng.max() > __urng.min() >= 0.
typedef typename std::make_unsigned<typename
- _UniformRandomNumberGenerator::result_type>::type __urntype;
+ _UniformRandomNumberGenerator::result_type>::type __urngtype;
typedef typename std::make_unsigned<result_type>::type __utype;
- typedef typename std::conditional<(sizeof(__urntype) > sizeof(__utype)),
- __urntype, __utype>::type __uctype;
+ typedef typename std::conditional<(sizeof(__urngtype)
+ > sizeof(__utype)),
+ __urngtype, __utype>::type __uctype;
- result_type __ret;
+ const __uctype __urngmin = __urng.min();
+ const __uctype __urngmax = __urng.max();
+ const __uctype __urngrange = __urngmax - __urngmin;
+ const __uctype __urange
+ = __uctype(__param.b()) - __uctype(__param.a());
- const __urntype __urnmin = __urng.min();
- const __urntype __urnmax = __urng.max();
- const __urntype __urnrange = __urnmax - __urnmin;
- const __uctype __urange = __param.b() - __param.a();
- const __uctype __udenom = (__urnrange <= __urange
- ? 1 : __urnrange / (__urange + 1));
- do
- __ret = (__urntype(__urng()) - __urnmin) / __udenom;
- while (__ret > __param.b() - __param.a());
+ __uctype __ret;
+
+ if (__urngrange > __urange)
+ {
+ // downscaling
+ const __uctype __uerange = __urange + 1; // __urange can be zero
+ const __uctype __scaling = __urngrange / __uerange;
+ const __uctype __past = __uerange * __scaling;
+ do
+ __ret = __uctype(__urng()) - __urngmin;
+ while (__ret >= __past);
+ __ret /= __scaling;
+ }
+ else if (__urngrange < __urange)
+ {
+ // upscaling
+ /*
+ Note that every value in [0, urange]
+ can be written uniquely as
+
+ (urngrange + 1) * high + low
+
+ where
+
+ high in [0, urange / (urngrange + 1)]
+
+ and
+
+ low in [0, urngrange].
+ */
+ __uctype __tmp; // wraparound control
+ do
+ {
+ const __uctype __uerngrange = __urngrange + 1;
+ __tmp = (__uerngrange * operator()
+ (__urng, param_type(0, __urange / __uerngrange)));
+ __ret = __tmp + (__uctype(__urng()) - __urngmin);
+ }
+ while (__ret > __urange || __ret < __tmp);
+ }
+ else
+ __ret = __uctype(__urng()) - __urngmin;
return __ret + __param.a();
}
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);
return __is;
}
-
+ // 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
param_type;
const double __y =
- _M_gd(__urng, param_type(__p.k(), __p.p() / (1.0 - __p.p())));
+ _M_gd(__urng, param_type(__p.k(), (1.0 - __p.p()) / __p.p()));
std::poisson_distribution<result_type> __poisson(__y);
return __poisson(__urng);
{
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);
if (_M_prob.size() < 2)
{
_M_prob.clear();
- _M_prob.push_back(1.0);
return;
}
operator()(_UniformRandomNumberGenerator& __urng,
const param_type& __param)
{
+ if (__param._M_cp.empty())
+ return result_type(0);
+
__detail::_Adaptor<_UniformRandomNumberGenerator, double>
__aurng(__urng);
piecewise_constant_distribution<_RealType>::param_type::
_M_initialize()
{
- if (_M_int.size() < 2)
+ if (_M_int.size() < 2
+ || (_M_int.size() == 2
+ && _M_int[0] == _RealType(0)
+ && _M_int[1] == _RealType(1)))
{
_M_int.clear();
- _M_int.reserve(2);
- _M_int.push_back(_RealType(0));
- _M_int.push_back(_RealType(1));
-
_M_den.clear();
- _M_den.push_back(1.0);
-
return;
}
__aurng(__urng);
const double __p = __aurng();
+ if (__param._M_cp.empty())
+ return __p;
+
auto __pos = std::lower_bound(__param._M_cp.begin(),
__param._M_cp.end(), __p);
const size_t __i = __pos - __param._M_cp.begin();
piecewise_linear_distribution<_RealType>::param_type::
_M_initialize()
{
- if (_M_int.size() < 2)
+ if (_M_int.size() < 2
+ || (_M_int.size() == 2
+ && _M_int[0] == _RealType(0)
+ && _M_int[1] == _RealType(1)
+ && _M_den[0] == _M_den[1]))
{
_M_int.clear();
- _M_int.reserve(2);
- _M_int.push_back(_RealType(0));
- _M_int.push_back(_RealType(1));
-
_M_den.clear();
- _M_den.reserve(2);
- _M_den.push_back(1.0);
- _M_den.push_back(1.0);
-
return;
}
__aurng(__urng);
const double __p = __aurng();
+ if (__param._M_cp.empty())
+ return __p;
+
auto __pos = std::lower_bound(__param._M_cp.begin(),
__param._M_cp.end(), __p);
const size_t __i = __pos - __param._M_cp.begin();
}
return __sum / __tmp;
}
-}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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