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random (xor_combine<>::_M_initialize_max_aux): New.

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2006-10-01  Paolo Carlini  <pcarlini@suse.de>

	* include/tr1/random (xor_combine<>::_M_initialize_max_aux): New.
	(xor_combine<>::operator()()): Tweak per N2079.
	* include/tr1/random.tcc (xor_combine<>::_M_initialize_max_aux):
	Define.
	(xor_combine<>::_M_initialize_max): Use it.
	* testsuite/tr1/5_numerical_facilities/random/xor_combine/
	cons/default.cc: Adjust.
	* docs/html/ext/tr1.html: Adjust.

From-SVN: r117353
This commit is contained in:
Paolo Carlini 2006-10-02 00:12:50 +00:00 committed by Paolo Carlini
parent a40776a295
commit 276116fdcc
5 changed files with 73 additions and 25 deletions
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11
libstdc++-v3/ChangeLog
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@ -1,3 +1,14 @@
2006-10-01 Paolo Carlini <pcarlini@suse.de>
* include/tr1/random (xor_combine<>::_M_initialize_max_aux): New.
(xor_combine<>::operator()()): Tweak per N2079.
* include/tr1/random.tcc (xor_combine<>::_M_initialize_max_aux):
Define.
(xor_combine<>::_M_initialize_max): Use it.
* testsuite/tr1/5_numerical_facilities/random/xor_combine/
cons/default.cc: Adjust.
* docs/html/ext/tr1.html: Adjust.
2006-10-01 Paolo Carlini <pcarlini@suse.de>
* include/ext/type_traits.h: Avoid _T, badname for some targets;

4
libstdc++-v3/docs/html/ext/tr1.html
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@ -706,7 +706,7 @@ release.
<td>done</td>
<td></td>
<td></td>
<td>Buggy min() and max()</td>
<td>operator()() per N2079</td>
</tr>
<tr>
<td>5.1.5</td>
@ -2307,7 +2307,7 @@ permitted in any medium, provided this notice is preserved.
<table width="100%" border="0">
<tr>
<td>
<!-- IGNORE DIFF -->Last modified 2006-08-25
<!-- IGNORE DIFF -->Last modified 2006-10-01
</td>
<td align="right" valign="bottom">
<a href="http://validator.w3.org/check/referer">

13
libstdc++-v3/include/tr1/random
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@ -1262,7 +1262,8 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
public:
/** The type of the generated random value. */
typedef typename __gnu_cxx::__conditional_type<(sizeof(_Result_type1) > sizeof(_Result_type2)),
typedef typename __gnu_cxx::__conditional_type<(sizeof(_Result_type1)
> sizeof(_Result_type2)),
_Result_type1, _Result_type2>::__type result_type;
// parameter values
@ -1310,7 +1311,6 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
base2() const
{ return _M_b2; }
// XXX Per N2032, but aren't always right...
result_type
min() const
{ return 0; }
@ -1322,9 +1322,13 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
/**
* Gets the next random number in the sequence.
*/
// NB: Not exactly the TR1 formula, per N2079 instead.
result_type
operator()()
{ return ((_M_b1() << shift1) ^ (_M_b2() << shift2)); }
{
return ((result_type(_M_b1() - _M_b1.min()) << shift1)
^ (result_type(_M_b2() - _M_b2.min()) << shift2));
}
/**
* Compares two %xor_combine random number generator objects of
@ -1397,6 +1401,9 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
void
_M_initialize_max();
result_type
_M_initialize_max_aux(result_type, result_type, int);
base1_type _M_b1;
base2_type _M_b2;
result_type _M_max;

68
libstdc++-v3/include/tr1/random.tcc
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@ -619,30 +619,59 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
_UniformRandomNumberGenerator2, __s2>::
_M_initialize_max()
{
const int __lshift = std::abs(__s1 - __s2);
const int __w = std::numeric_limits<result_type>::digits;
result_type __m1 = _M_b1.max() - _M_b1.min();
result_type __m2 = _M_b2.max() - _M_b2.min();
const result_type __m1 =
std::min(result_type(_M_b1.max() - _M_b1.min()),
_Shift<result_type, __w - __s1>::__value - 1);
// NB: in TR1 s1 is not required to be >= s2.
if (__s1 >= __s2)
__m1 <<= __lshift;
const result_type __m2 =
std::min(result_type(_M_b2.max() - _M_b2.min()),
_Shift<result_type, __w - __s2>::__value - 1);
// NB: In TR1 s1 is not required to be >= s2.
if (__s1 < __s2)
_M_max = _M_initialize_max_aux(__m2, __m1, __s2 - __s1) << __s1;
else
__m2 <<= __lshift;
_M_max = _M_initialize_max_aux(__m1, __m2, __s1 - __s2) << __s2;
}
result_type __a = __m1 & __m2;
const result_type __b = __m1 | __m2;
template<class _UniformRandomNumberGenerator1, int __s1,
class _UniformRandomNumberGenerator2, int __s2>
typename xor_combine<_UniformRandomNumberGenerator1, __s1,
_UniformRandomNumberGenerator2, __s2>::result_type
xor_combine<_UniformRandomNumberGenerator1, __s1,
_UniformRandomNumberGenerator2, __s2>::
_M_initialize_max_aux(result_type __a, result_type __b, int __d)
{
const result_type __two2d = result_type(1) << __d;
const result_type __c = __a * __two2d;
result_type __c = 0;
if (__a)
{
result_type __k;
for (__k = 0; __a != 1; __a >>= 1)
++__k;
__c = (result_type(1) << __k) - 1;
}
if (__a == 0 || __b < __two2d)
return __c + __b;
_M_max = (__c | __b) << __lshift;
const result_type __t = std::max(__c, __b);
const result_type __u = std::min(__c, __b);
result_type __ub = __u;
result_type __p;
for (__p = 0; __ub != 1; __ub >>= 1)
++__p;
const result_type __two2p = result_type(1) << __p;
const result_type __k = __t / __two2p;
if (__k & 1)
return (__k + 1) * __two2p - 1;
if (__c >= __b)
return (__k + 1) * __two2p + _M_initialize_max_aux((__t % __two2p)
/ __two2d,
__u % __two2p, __d);
else
return (__k + 1) * __two2p + _M_initialize_max_aux((__u % __two2p)
/ __two2d,
__t % __two2p, __d);
}
template<class _UniformRandomNumberGenerator1, int __s1,
@ -852,7 +881,8 @@ _GLIBCXX_BEGIN_NAMESPACE(tr1)
continue;
}
else if (__u <= __c3)
// XXX This case not in the book, nor in the Errata...
// NB: This case not in the book, nor in the Errata,
// but should be ok...
__x = -1;
else if (__u <= __c4)
__x = 0;

2
libstdc++-v3/testsuite/tr1/5_numerical_facilities/random/xor_combine/cons/default.cc
View File

@ -36,7 +36,7 @@ test01()
minstd_rand0, 2
> x;
VERIFY( x() == 32642 );
VERIFY( x() == 32644 );
}
int main()