1 // random number generation (out of line) -*- C++ -*-
2 
3 // Copyright (C) 2009, 2010 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 
26 /** @file tr1/random.tcc
27  *  This is an internal header file, included by other library headers.
28  *  Do not attempt to use it directly. @headername{tr1/random}
29  */
30 
31 #ifndef _GLIBCXX_TR1_RANDOM_TCC
32 #define _GLIBCXX_TR1_RANDOM_TCC 1
33 
34 namespace std _GLIBCXX_VISIBILITY(default)
35 {
36 namespace tr1
37 {
38   /*
39    * (Further) implementation-space details.
40    */
41   namespace __detail
42   {
43   _GLIBCXX_BEGIN_NAMESPACE_VERSION
44 
45     // General case for x = (ax + c) mod m -- use Schrage's algorithm to avoid
46     // integer overflow.
47     //
48     // Because a and c are compile-time integral constants the compiler kindly
49     // elides any unreachable paths.
50     //
51     // Preconditions:  a > 0, m > 0.
52     //
53     template<typename _Tp, _Tp __a, _Tp __c, _Tp __m, bool>
54       struct _Mod
55       {
56 	static _Tp
57 	__calc(_Tp __x)
58 	{
59 	  if (__a == 1)
60 	    __x %= __m;
61 	  else
62 	    {
63 	      static const _Tp __q = __m / __a;
64 	      static const _Tp __r = __m % __a;
65 
66 	      _Tp __t1 = __a * (__x % __q);
67 	      _Tp __t2 = __r * (__x / __q);
68 	      if (__t1 >= __t2)
69 		__x = __t1 - __t2;
70 	      else
71 		__x = __m - __t2 + __t1;
72 	    }
73 
74 	  if (__c != 0)
75 	    {
76 	      const _Tp __d = __m - __x;
77 	      if (__d > __c)
78 		__x += __c;
79 	      else
80 		__x = __c - __d;
81 	    }
82 	  return __x;
83 	}
84       };
85 
86     // Special case for m == 0 -- use unsigned integer overflow as modulo
87     // operator.
88     template<typename _Tp, _Tp __a, _Tp __c, _Tp __m>
89       struct _Mod<_Tp, __a, __c, __m, true>
90       {
91 	static _Tp
92 	__calc(_Tp __x)
93 	{ return __a * __x + __c; }
94       };
95   _GLIBCXX_END_NAMESPACE_VERSION
96   } // namespace __detail
97 
98 _GLIBCXX_BEGIN_NAMESPACE_VERSION
99 
100   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
101     const _UIntType
102     linear_congruential<_UIntType, __a, __c, __m>::multiplier;
103 
104   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
105     const _UIntType
106     linear_congruential<_UIntType, __a, __c, __m>::increment;
107 
108   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
109     const _UIntType
110     linear_congruential<_UIntType, __a, __c, __m>::modulus;
111 
112   /**
113    * Seeds the LCR with integral value @p __x0, adjusted so that the
114    * ring identity is never a member of the convergence set.
115    */
116   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
117     void
118     linear_congruential<_UIntType, __a, __c, __m>::
119     seed(unsigned long __x0)
120     {
121       if ((__detail::__mod<_UIntType, 1, 0, __m>(__c) == 0)
122 	  && (__detail::__mod<_UIntType, 1, 0, __m>(__x0) == 0))
123 	_M_x = __detail::__mod<_UIntType, 1, 0, __m>(1);
124       else
125 	_M_x = __detail::__mod<_UIntType, 1, 0, __m>(__x0);
126     }
127 
128   /**
129    * Seeds the LCR engine with a value generated by @p __g.
130    */
131   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
132     template<class _Gen>
133       void
134       linear_congruential<_UIntType, __a, __c, __m>::
135       seed(_Gen& __g, false_type)
136       {
137 	_UIntType __x0 = __g();
138 	if ((__detail::__mod<_UIntType, 1, 0, __m>(__c) == 0)
139 	    && (__detail::__mod<_UIntType, 1, 0, __m>(__x0) == 0))
140 	  _M_x = __detail::__mod<_UIntType, 1, 0, __m>(1);
141 	else
142 	  _M_x = __detail::__mod<_UIntType, 1, 0, __m>(__x0);
143       }
144 
145   /**
146    * Gets the next generated value in sequence.
147    */
148   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
149     typename linear_congruential<_UIntType, __a, __c, __m>::result_type
150     linear_congruential<_UIntType, __a, __c, __m>::
151     operator()()
152     {
153       _M_x = __detail::__mod<_UIntType, __a, __c, __m>(_M_x);
154       return _M_x;
155     }
156 
157   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
158 	   typename _CharT, typename _Traits>
159     std::basic_ostream<_CharT, _Traits>&
160     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
161 	       const linear_congruential<_UIntType, __a, __c, __m>& __lcr)
162     {
163       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
164       typedef typename __ostream_type::ios_base    __ios_base;
165 
166       const typename __ios_base::fmtflags __flags = __os.flags();
167       const _CharT __fill = __os.fill();
168       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
169       __os.fill(__os.widen(' '));
170 
171       __os << __lcr._M_x;
172 
173       __os.flags(__flags);
174       __os.fill(__fill);
175       return __os;
176     }
177 
178   template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
179 	   typename _CharT, typename _Traits>
180     std::basic_istream<_CharT, _Traits>&
181     operator>>(std::basic_istream<_CharT, _Traits>& __is,
182 	       linear_congruential<_UIntType, __a, __c, __m>& __lcr)
183     {
184       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
185       typedef typename __istream_type::ios_base    __ios_base;
186 
187       const typename __ios_base::fmtflags __flags = __is.flags();
188       __is.flags(__ios_base::dec);
189 
190       __is >> __lcr._M_x;
191 
192       __is.flags(__flags);
193       return __is;
194     }
195 
196 
197   template<class _UIntType, int __w, int __n, int __m, int __r,
198 	   _UIntType __a, int __u, int __s,
199 	   _UIntType __b, int __t, _UIntType __c, int __l>
200     const int
201     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
202 		     __b, __t, __c, __l>::word_size;
203 
204   template<class _UIntType, int __w, int __n, int __m, int __r,
205 	   _UIntType __a, int __u, int __s,
206 	   _UIntType __b, int __t, _UIntType __c, int __l>
207     const int
208     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
209 		     __b, __t, __c, __l>::state_size;
210 
211   template<class _UIntType, int __w, int __n, int __m, int __r,
212 	   _UIntType __a, int __u, int __s,
213 	   _UIntType __b, int __t, _UIntType __c, int __l>
214     const int
215     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
216 		     __b, __t, __c, __l>::shift_size;
217 
218   template<class _UIntType, int __w, int __n, int __m, int __r,
219 	   _UIntType __a, int __u, int __s,
220 	   _UIntType __b, int __t, _UIntType __c, int __l>
221     const int
222     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
223 		     __b, __t, __c, __l>::mask_bits;
224 
225   template<class _UIntType, int __w, int __n, int __m, int __r,
226 	   _UIntType __a, int __u, int __s,
227 	   _UIntType __b, int __t, _UIntType __c, int __l>
228     const _UIntType
229     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
230 		     __b, __t, __c, __l>::parameter_a;
231 
232   template<class _UIntType, int __w, int __n, int __m, int __r,
233 	   _UIntType __a, int __u, int __s,
234 	   _UIntType __b, int __t, _UIntType __c, int __l>
235     const int
236     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
237 		     __b, __t, __c, __l>::output_u;
238 
239   template<class _UIntType, int __w, int __n, int __m, int __r,
240 	   _UIntType __a, int __u, int __s,
241 	   _UIntType __b, int __t, _UIntType __c, int __l>
242     const int
243     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
244 		     __b, __t, __c, __l>::output_s;
245 
246   template<class _UIntType, int __w, int __n, int __m, int __r,
247 	   _UIntType __a, int __u, int __s,
248 	   _UIntType __b, int __t, _UIntType __c, int __l>
249     const _UIntType
250     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
251 		     __b, __t, __c, __l>::output_b;
252 
253   template<class _UIntType, int __w, int __n, int __m, int __r,
254 	   _UIntType __a, int __u, int __s,
255 	   _UIntType __b, int __t, _UIntType __c, int __l>
256     const int
257     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
258 		     __b, __t, __c, __l>::output_t;
259 
260   template<class _UIntType, int __w, int __n, int __m, int __r,
261 	   _UIntType __a, int __u, int __s,
262 	   _UIntType __b, int __t, _UIntType __c, int __l>
263     const _UIntType
264     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
265 		     __b, __t, __c, __l>::output_c;
266 
267   template<class _UIntType, int __w, int __n, int __m, int __r,
268 	   _UIntType __a, int __u, int __s,
269 	   _UIntType __b, int __t, _UIntType __c, int __l>
270     const int
271     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
272 		     __b, __t, __c, __l>::output_l;
273 
274   template<class _UIntType, int __w, int __n, int __m, int __r,
275 	   _UIntType __a, int __u, int __s,
276 	   _UIntType __b, int __t, _UIntType __c, int __l>
277     void
278     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
279 		     __b, __t, __c, __l>::
280     seed(unsigned long __value)
281     {
282       _M_x[0] = __detail::__mod<_UIntType, 1, 0,
283 	__detail::_Shift<_UIntType, __w>::__value>(__value);
284 
285       for (int __i = 1; __i < state_size; ++__i)
286 	{
287 	  _UIntType __x = _M_x[__i - 1];
288 	  __x ^= __x >> (__w - 2);
289 	  __x *= 1812433253ul;
290 	  __x += __i;
291 	  _M_x[__i] = __detail::__mod<_UIntType, 1, 0,
292 	    __detail::_Shift<_UIntType, __w>::__value>(__x);
293 	}
294       _M_p = state_size;
295     }
296 
297   template<class _UIntType, int __w, int __n, int __m, int __r,
298 	   _UIntType __a, int __u, int __s,
299 	   _UIntType __b, int __t, _UIntType __c, int __l>
300     template<class _Gen>
301       void
302       mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
303 		       __b, __t, __c, __l>::
304       seed(_Gen& __gen, false_type)
305       {
306 	for (int __i = 0; __i < state_size; ++__i)
307 	  _M_x[__i] = __detail::__mod<_UIntType, 1, 0,
308 	    __detail::_Shift<_UIntType, __w>::__value>(__gen());
309 	_M_p = state_size;
310       }
311 
312   template<class _UIntType, int __w, int __n, int __m, int __r,
313 	   _UIntType __a, int __u, int __s,
314 	   _UIntType __b, int __t, _UIntType __c, int __l>
315     typename
316     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
317 		     __b, __t, __c, __l>::result_type
318     mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
319 		     __b, __t, __c, __l>::
320     operator()()
321     {
322       // Reload the vector - cost is O(n) amortized over n calls.
323       if (_M_p >= state_size)
324 	{
325 	  const _UIntType __upper_mask = (~_UIntType()) << __r;
326 	  const _UIntType __lower_mask = ~__upper_mask;
327 
328 	  for (int __k = 0; __k < (__n - __m); ++__k)
329 	    {
330 	      _UIntType __y = ((_M_x[__k] & __upper_mask)
331 			       | (_M_x[__k + 1] & __lower_mask));
332 	      _M_x[__k] = (_M_x[__k + __m] ^ (__y >> 1)
333 			   ^ ((__y & 0x01) ? __a : 0));
334 	    }
335 
336 	  for (int __k = (__n - __m); __k < (__n - 1); ++__k)
337 	    {
338 	      _UIntType __y = ((_M_x[__k] & __upper_mask)
339 			       | (_M_x[__k + 1] & __lower_mask));
340 	      _M_x[__k] = (_M_x[__k + (__m - __n)] ^ (__y >> 1)
341 			   ^ ((__y & 0x01) ? __a : 0));
342 	    }
343 
344 	  _UIntType __y = ((_M_x[__n - 1] & __upper_mask)
345 			   | (_M_x[0] & __lower_mask));
346 	  _M_x[__n - 1] = (_M_x[__m - 1] ^ (__y >> 1)
347 			   ^ ((__y & 0x01) ? __a : 0));
348 	  _M_p = 0;
349 	}
350 
351       // Calculate o(x(i)).
352       result_type __z = _M_x[_M_p++];
353       __z ^= (__z >> __u);
354       __z ^= (__z << __s) & __b;
355       __z ^= (__z << __t) & __c;
356       __z ^= (__z >> __l);
357 
358       return __z;
359     }
360 
361   template<class _UIntType, int __w, int __n, int __m, int __r,
362 	   _UIntType __a, int __u, int __s, _UIntType __b, int __t,
363 	   _UIntType __c, int __l,
364 	   typename _CharT, typename _Traits>
365     std::basic_ostream<_CharT, _Traits>&
366     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
367 	       const mersenne_twister<_UIntType, __w, __n, __m,
368 	       __r, __a, __u, __s, __b, __t, __c, __l>& __x)
369     {
370       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
371       typedef typename __ostream_type::ios_base    __ios_base;
372 
373       const typename __ios_base::fmtflags __flags = __os.flags();
374       const _CharT __fill = __os.fill();
375       const _CharT __space = __os.widen(' ');
376       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
377       __os.fill(__space);
378 
379       for (int __i = 0; __i < __n - 1; ++__i)
380 	__os << __x._M_x[__i] << __space;
381       __os << __x._M_x[__n - 1];
382 
383       __os.flags(__flags);
384       __os.fill(__fill);
385       return __os;
386     }
387 
388   template<class _UIntType, int __w, int __n, int __m, int __r,
389 	   _UIntType __a, int __u, int __s, _UIntType __b, int __t,
390 	   _UIntType __c, int __l,
391 	   typename _CharT, typename _Traits>
392     std::basic_istream<_CharT, _Traits>&
393     operator>>(std::basic_istream<_CharT, _Traits>& __is,
394 	       mersenne_twister<_UIntType, __w, __n, __m,
395 	       __r, __a, __u, __s, __b, __t, __c, __l>& __x)
396     {
397       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
398       typedef typename __istream_type::ios_base    __ios_base;
399 
400       const typename __ios_base::fmtflags __flags = __is.flags();
401       __is.flags(__ios_base::dec | __ios_base::skipws);
402 
403       for (int __i = 0; __i < __n; ++__i)
404 	__is >> __x._M_x[__i];
405 
406       __is.flags(__flags);
407       return __is;
408     }
409 
410 
411   template<typename _IntType, _IntType __m, int __s, int __r>
412     const _IntType
413     subtract_with_carry<_IntType, __m, __s, __r>::modulus;
414 
415   template<typename _IntType, _IntType __m, int __s, int __r>
416     const int
417     subtract_with_carry<_IntType, __m, __s, __r>::long_lag;
418 
419   template<typename _IntType, _IntType __m, int __s, int __r>
420     const int
421     subtract_with_carry<_IntType, __m, __s, __r>::short_lag;
422 
423   template<typename _IntType, _IntType __m, int __s, int __r>
424     void
425     subtract_with_carry<_IntType, __m, __s, __r>::
426     seed(unsigned long __value)
427     {
428       if (__value == 0)
429 	__value = 19780503;
430 
431       std::tr1::linear_congruential<unsigned long, 40014, 0, 2147483563>
432 	__lcg(__value);
433 
434       for (int __i = 0; __i < long_lag; ++__i)
435 	_M_x[__i] = __detail::__mod<_UIntType, 1, 0, modulus>(__lcg());
436 
437       _M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
438       _M_p = 0;
439     }
440 
441   template<typename _IntType, _IntType __m, int __s, int __r>
442     template<class _Gen>
443       void
444       subtract_with_carry<_IntType, __m, __s, __r>::
445       seed(_Gen& __gen, false_type)
446       {
447 	const int __n = (std::numeric_limits<_UIntType>::digits + 31) / 32;
448 
449 	for (int __i = 0; __i < long_lag; ++__i)
450 	  {
451 	    _UIntType __tmp = 0;
452 	    _UIntType __factor = 1;
453 	    for (int __j = 0; __j < __n; ++__j)
454 	      {
455 		__tmp += __detail::__mod<__detail::_UInt32Type, 1, 0, 0>
456 		         (__gen()) * __factor;
457 		__factor *= __detail::_Shift<_UIntType, 32>::__value;
458 	      }
459 	    _M_x[__i] = __detail::__mod<_UIntType, 1, 0, modulus>(__tmp);
460 	  }
461 	_M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
462 	_M_p = 0;
463       }
464 
465   template<typename _IntType, _IntType __m, int __s, int __r>
466     typename subtract_with_carry<_IntType, __m, __s, __r>::result_type
467     subtract_with_carry<_IntType, __m, __s, __r>::
468     operator()()
469     {
470       // Derive short lag index from current index.
471       int __ps = _M_p - short_lag;
472       if (__ps < 0)
473 	__ps += long_lag;
474 
475       // Calculate new x(i) without overflow or division.
476       // NB: Thanks to the requirements for _IntType, _M_x[_M_p] + _M_carry
477       // cannot overflow.
478       _UIntType __xi;
479       if (_M_x[__ps] >= _M_x[_M_p] + _M_carry)
480 	{
481 	  __xi = _M_x[__ps] - _M_x[_M_p] - _M_carry;
482 	  _M_carry = 0;
483 	}
484       else
485 	{
486 	  __xi = modulus - _M_x[_M_p] - _M_carry + _M_x[__ps];
487 	  _M_carry = 1;
488 	}
489       _M_x[_M_p] = __xi;
490 
491       // Adjust current index to loop around in ring buffer.
492       if (++_M_p >= long_lag)
493 	_M_p = 0;
494 
495       return __xi;
496     }
497 
498   template<typename _IntType, _IntType __m, int __s, int __r,
499 	   typename _CharT, typename _Traits>
500     std::basic_ostream<_CharT, _Traits>&
501     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
502 	       const subtract_with_carry<_IntType, __m, __s, __r>& __x)
503     {
504       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
505       typedef typename __ostream_type::ios_base    __ios_base;
506 
507       const typename __ios_base::fmtflags __flags = __os.flags();
508       const _CharT __fill = __os.fill();
509       const _CharT __space = __os.widen(' ');
510       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
511       __os.fill(__space);
512 
513       for (int __i = 0; __i < __r; ++__i)
514 	__os << __x._M_x[__i] << __space;
515       __os << __x._M_carry;
516 
517       __os.flags(__flags);
518       __os.fill(__fill);
519       return __os;
520     }
521 
522   template<typename _IntType, _IntType __m, int __s, int __r,
523 	   typename _CharT, typename _Traits>
524     std::basic_istream<_CharT, _Traits>&
525     operator>>(std::basic_istream<_CharT, _Traits>& __is,
526 	       subtract_with_carry<_IntType, __m, __s, __r>& __x)
527     {
528       typedef std::basic_ostream<_CharT, _Traits>  __istream_type;
529       typedef typename __istream_type::ios_base    __ios_base;
530 
531       const typename __ios_base::fmtflags __flags = __is.flags();
532       __is.flags(__ios_base::dec | __ios_base::skipws);
533 
534       for (int __i = 0; __i < __r; ++__i)
535 	__is >> __x._M_x[__i];
536       __is >> __x._M_carry;
537 
538       __is.flags(__flags);
539       return __is;
540     }
541 
542 
543   template<typename _RealType, int __w, int __s, int __r>
544     const int
545     subtract_with_carry_01<_RealType, __w, __s, __r>::word_size;
546 
547   template<typename _RealType, int __w, int __s, int __r>
548     const int
549     subtract_with_carry_01<_RealType, __w, __s, __r>::long_lag;
550 
551   template<typename _RealType, int __w, int __s, int __r>
552     const int
553     subtract_with_carry_01<_RealType, __w, __s, __r>::short_lag;
554 
555   template<typename _RealType, int __w, int __s, int __r>
556     void
557     subtract_with_carry_01<_RealType, __w, __s, __r>::
558     _M_initialize_npows()
559     {
560       for (int __j = 0; __j < __n; ++__j)
561 #if _GLIBCXX_USE_C99_MATH_TR1
562 	_M_npows[__j] = std::tr1::ldexp(_RealType(1), -__w + __j * 32);
563 #else
564         _M_npows[__j] = std::pow(_RealType(2), -__w + __j * 32);
565 #endif
566     }
567 
568   template<typename _RealType, int __w, int __s, int __r>
569     void
570     subtract_with_carry_01<_RealType, __w, __s, __r>::
571     seed(unsigned long __value)
572     {
573       if (__value == 0)
574 	__value = 19780503;
575 
576       // _GLIBCXX_RESOLVE_LIB_DEFECTS
577       // 512. Seeding subtract_with_carry_01 from a single unsigned long.
578       std::tr1::linear_congruential<unsigned long, 40014, 0, 2147483563>
579 	__lcg(__value);
580 
581       this->seed(__lcg);
582     }
583 
584   template<typename _RealType, int __w, int __s, int __r>
585     template<class _Gen>
586       void
587       subtract_with_carry_01<_RealType, __w, __s, __r>::
588       seed(_Gen& __gen, false_type)
589       {
590 	for (int __i = 0; __i < long_lag; ++__i)
591 	  {
592 	    for (int __j = 0; __j < __n - 1; ++__j)
593 	      _M_x[__i][__j] = __detail::__mod<_UInt32Type, 1, 0, 0>(__gen());
594 	    _M_x[__i][__n - 1] = __detail::__mod<_UInt32Type, 1, 0,
595 	      __detail::_Shift<_UInt32Type, __w % 32>::__value>(__gen());
596 	  }
597 
598 	_M_carry = 1;
599 	for (int __j = 0; __j < __n; ++__j)
600 	  if (_M_x[long_lag - 1][__j] != 0)
601 	    {
602 	      _M_carry = 0;
603 	      break;
604 	    }
605 
606 	_M_p = 0;
607       }
608 
609   template<typename _RealType, int __w, int __s, int __r>
610     typename subtract_with_carry_01<_RealType, __w, __s, __r>::result_type
611     subtract_with_carry_01<_RealType, __w, __s, __r>::
612     operator()()
613     {
614       // Derive short lag index from current index.
615       int __ps = _M_p - short_lag;
616       if (__ps < 0)
617 	__ps += long_lag;
618 
619       _UInt32Type __new_carry;
620       for (int __j = 0; __j < __n - 1; ++__j)
621 	{
622 	  if (_M_x[__ps][__j] > _M_x[_M_p][__j]
623 	      || (_M_x[__ps][__j] == _M_x[_M_p][__j] && _M_carry == 0))
624 	    __new_carry = 0;
625 	  else
626 	    __new_carry = 1;
627 
628 	  _M_x[_M_p][__j] = _M_x[__ps][__j] - _M_x[_M_p][__j] - _M_carry;
629 	  _M_carry = __new_carry;
630 	}
631 
632       if (_M_x[__ps][__n - 1] > _M_x[_M_p][__n - 1]
633 	  || (_M_x[__ps][__n - 1] == _M_x[_M_p][__n - 1] && _M_carry == 0))
634 	__new_carry = 0;
635       else
636 	__new_carry = 1;
637 
638       _M_x[_M_p][__n - 1] = __detail::__mod<_UInt32Type, 1, 0,
639 	__detail::_Shift<_UInt32Type, __w % 32>::__value>
640 	(_M_x[__ps][__n - 1] - _M_x[_M_p][__n - 1] - _M_carry);
641       _M_carry = __new_carry;
642 
643       result_type __ret = 0.0;
644       for (int __j = 0; __j < __n; ++__j)
645 	__ret += _M_x[_M_p][__j] * _M_npows[__j];
646 
647       // Adjust current index to loop around in ring buffer.
648       if (++_M_p >= long_lag)
649 	_M_p = 0;
650 
651       return __ret;
652     }
653 
654   template<typename _RealType, int __w, int __s, int __r,
655 	   typename _CharT, typename _Traits>
656     std::basic_ostream<_CharT, _Traits>&
657     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
658 	       const subtract_with_carry_01<_RealType, __w, __s, __r>& __x)
659     {
660       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
661       typedef typename __ostream_type::ios_base    __ios_base;
662 
663       const typename __ios_base::fmtflags __flags = __os.flags();
664       const _CharT __fill = __os.fill();
665       const _CharT __space = __os.widen(' ');
666       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
667       __os.fill(__space);
668 
669       for (int __i = 0; __i < __r; ++__i)
670 	for (int __j = 0; __j < __x.__n; ++__j)
671 	  __os << __x._M_x[__i][__j] << __space;
672       __os << __x._M_carry;
673 
674       __os.flags(__flags);
675       __os.fill(__fill);
676       return __os;
677     }
678 
679   template<typename _RealType, int __w, int __s, int __r,
680 	   typename _CharT, typename _Traits>
681     std::basic_istream<_CharT, _Traits>&
682     operator>>(std::basic_istream<_CharT, _Traits>& __is,
683 	       subtract_with_carry_01<_RealType, __w, __s, __r>& __x)
684     {
685       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
686       typedef typename __istream_type::ios_base    __ios_base;
687 
688       const typename __ios_base::fmtflags __flags = __is.flags();
689       __is.flags(__ios_base::dec | __ios_base::skipws);
690 
691       for (int __i = 0; __i < __r; ++__i)
692 	for (int __j = 0; __j < __x.__n; ++__j)
693 	  __is >> __x._M_x[__i][__j];
694       __is >> __x._M_carry;
695 
696       __is.flags(__flags);
697       return __is;
698     }
699 
700   template<class _UniformRandomNumberGenerator, int __p, int __r>
701     const int
702     discard_block<_UniformRandomNumberGenerator, __p, __r>::block_size;
703 
704   template<class _UniformRandomNumberGenerator, int __p, int __r>
705     const int
706     discard_block<_UniformRandomNumberGenerator, __p, __r>::used_block;
707 
708   template<class _UniformRandomNumberGenerator, int __p, int __r>
709     typename discard_block<_UniformRandomNumberGenerator,
710 			   __p, __r>::result_type
711     discard_block<_UniformRandomNumberGenerator, __p, __r>::
712     operator()()
713     {
714       if (_M_n >= used_block)
715 	{
716 	  while (_M_n < block_size)
717 	    {
718 	      _M_b();
719 	      ++_M_n;
720 	    }
721 	  _M_n = 0;
722 	}
723       ++_M_n;
724       return _M_b();
725     }
726 
727   template<class _UniformRandomNumberGenerator, int __p, int __r,
728 	   typename _CharT, typename _Traits>
729     std::basic_ostream<_CharT, _Traits>&
730     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
731 	       const discard_block<_UniformRandomNumberGenerator,
732 	       __p, __r>& __x)
733     {
734       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
735       typedef typename __ostream_type::ios_base    __ios_base;
736 
737       const typename __ios_base::fmtflags __flags = __os.flags();
738       const _CharT __fill = __os.fill();
739       const _CharT __space = __os.widen(' ');
740       __os.flags(__ios_base::dec | __ios_base::fixed
741 		 | __ios_base::left);
742       __os.fill(__space);
743 
744       __os << __x._M_b << __space << __x._M_n;
745 
746       __os.flags(__flags);
747       __os.fill(__fill);
748       return __os;
749     }
750 
751   template<class _UniformRandomNumberGenerator, int __p, int __r,
752 	   typename _CharT, typename _Traits>
753     std::basic_istream<_CharT, _Traits>&
754     operator>>(std::basic_istream<_CharT, _Traits>& __is,
755 	       discard_block<_UniformRandomNumberGenerator, __p, __r>& __x)
756     {
757       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
758       typedef typename __istream_type::ios_base    __ios_base;
759 
760       const typename __ios_base::fmtflags __flags = __is.flags();
761       __is.flags(__ios_base::dec | __ios_base::skipws);
762 
763       __is >> __x._M_b >> __x._M_n;
764 
765       __is.flags(__flags);
766       return __is;
767     }
768 
769 
770   template<class _UniformRandomNumberGenerator1, int __s1,
771 	   class _UniformRandomNumberGenerator2, int __s2>
772     const int
773     xor_combine<_UniformRandomNumberGenerator1, __s1,
774 		_UniformRandomNumberGenerator2, __s2>::shift1;
775 
776   template<class _UniformRandomNumberGenerator1, int __s1,
777 	   class _UniformRandomNumberGenerator2, int __s2>
778     const int
779     xor_combine<_UniformRandomNumberGenerator1, __s1,
780 		_UniformRandomNumberGenerator2, __s2>::shift2;
781 
782   template<class _UniformRandomNumberGenerator1, int __s1,
783 	   class _UniformRandomNumberGenerator2, int __s2>
784     void
785     xor_combine<_UniformRandomNumberGenerator1, __s1,
786 		_UniformRandomNumberGenerator2, __s2>::
787     _M_initialize_max()
788     {
789       const int __w = std::numeric_limits<result_type>::digits;
790 
791       const result_type __m1 =
792 	std::min(result_type(_M_b1.max() - _M_b1.min()),
793 		 __detail::_Shift<result_type, __w - __s1>::__value - 1);
794 
795       const result_type __m2 =
796 	std::min(result_type(_M_b2.max() - _M_b2.min()),
797 		 __detail::_Shift<result_type, __w - __s2>::__value - 1);
798 
799       // NB: In TR1 s1 is not required to be >= s2.
800       if (__s1 < __s2)
801 	_M_max = _M_initialize_max_aux(__m2, __m1, __s2 - __s1) << __s1;
802       else
803 	_M_max = _M_initialize_max_aux(__m1, __m2, __s1 - __s2) << __s2;
804     }
805 
806   template<class _UniformRandomNumberGenerator1, int __s1,
807 	   class _UniformRandomNumberGenerator2, int __s2>
808     typename xor_combine<_UniformRandomNumberGenerator1, __s1,
809 			 _UniformRandomNumberGenerator2, __s2>::result_type
810     xor_combine<_UniformRandomNumberGenerator1, __s1,
811 		_UniformRandomNumberGenerator2, __s2>::
812     _M_initialize_max_aux(result_type __a, result_type __b, int __d)
813     {
814       const result_type __two2d = result_type(1) << __d;
815       const result_type __c = __a * __two2d;
816 
817       if (__a == 0 || __b < __two2d)
818 	return __c + __b;
819 
820       const result_type __t = std::max(__c, __b);
821       const result_type __u = std::min(__c, __b);
822 
823       result_type __ub = __u;
824       result_type __p;
825       for (__p = 0; __ub != 1; __ub >>= 1)
826 	++__p;
827 
828       const result_type __two2p = result_type(1) << __p;
829       const result_type __k = __t / __two2p;
830 
831       if (__k & 1)
832 	return (__k + 1) * __two2p - 1;
833 
834       if (__c >= __b)
835 	return (__k + 1) * __two2p + _M_initialize_max_aux((__t % __two2p)
836 							   / __two2d,
837 							   __u % __two2p, __d);
838       else
839 	return (__k + 1) * __two2p + _M_initialize_max_aux((__u % __two2p)
840 							   / __two2d,
841 							   __t % __two2p, __d);
842     }
843 
844   template<class _UniformRandomNumberGenerator1, int __s1,
845 	   class _UniformRandomNumberGenerator2, int __s2,
846 	   typename _CharT, typename _Traits>
847     std::basic_ostream<_CharT, _Traits>&
848     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
849 	       const xor_combine<_UniformRandomNumberGenerator1, __s1,
850 	       _UniformRandomNumberGenerator2, __s2>& __x)
851     {
852       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
853       typedef typename __ostream_type::ios_base    __ios_base;
854 
855       const typename __ios_base::fmtflags __flags = __os.flags();
856       const _CharT __fill = __os.fill();
857       const _CharT __space = __os.widen(' ');
858       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
859       __os.fill(__space);
860 
861       __os << __x.base1() << __space << __x.base2();
862 
863       __os.flags(__flags);
864       __os.fill(__fill);
865       return __os;
866     }
867 
868   template<class _UniformRandomNumberGenerator1, int __s1,
869 	   class _UniformRandomNumberGenerator2, int __s2,
870 	   typename _CharT, typename _Traits>
871     std::basic_istream<_CharT, _Traits>&
872     operator>>(std::basic_istream<_CharT, _Traits>& __is,
873 	       xor_combine<_UniformRandomNumberGenerator1, __s1,
874 	       _UniformRandomNumberGenerator2, __s2>& __x)
875     {
876       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
877       typedef typename __istream_type::ios_base    __ios_base;
878 
879       const typename __ios_base::fmtflags __flags = __is.flags();
880       __is.flags(__ios_base::skipws);
881 
882       __is >> __x._M_b1 >> __x._M_b2;
883 
884       __is.flags(__flags);
885       return __is;
886     }
887 
888 
889   template<typename _IntType>
890     template<typename _UniformRandomNumberGenerator>
891       typename uniform_int<_IntType>::result_type
892       uniform_int<_IntType>::
893       _M_call(_UniformRandomNumberGenerator& __urng,
894 	      result_type __min, result_type __max, true_type)
895       {
896 	// XXX Must be fixed to work well for *arbitrary* __urng.max(),
897 	// __urng.min(), __max, __min.  Currently works fine only in the
898 	// most common case __urng.max() - __urng.min() >= __max - __min,
899 	// with __urng.max() > __urng.min() >= 0.
900 	typedef typename __gnu_cxx::__add_unsigned<typename
901 	  _UniformRandomNumberGenerator::result_type>::__type __urntype;
902 	typedef typename __gnu_cxx::__add_unsigned<result_type>::__type
903 	                                                      __utype;
904 	typedef typename __gnu_cxx::__conditional_type<(sizeof(__urntype)
905 							> sizeof(__utype)),
906 	  __urntype, __utype>::__type                         __uctype;
907 
908 	result_type __ret;
909 
910 	const __urntype __urnmin = __urng.min();
911 	const __urntype __urnmax = __urng.max();
912 	const __urntype __urnrange = __urnmax - __urnmin;
913 	const __uctype __urange = __max - __min;
914 	const __uctype __udenom = (__urnrange <= __urange
915 				   ? 1 : __urnrange / (__urange + 1));
916 	do
917 	  __ret = (__urntype(__urng()) -  __urnmin) / __udenom;
918 	while (__ret > __max - __min);
919 
920 	return __ret + __min;
921       }
922 
923   template<typename _IntType, typename _CharT, typename _Traits>
924     std::basic_ostream<_CharT, _Traits>&
925     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
926 	       const uniform_int<_IntType>& __x)
927     {
928       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
929       typedef typename __ostream_type::ios_base    __ios_base;
930 
931       const typename __ios_base::fmtflags __flags = __os.flags();
932       const _CharT __fill = __os.fill();
933       const _CharT __space = __os.widen(' ');
934       __os.flags(__ios_base::scientific | __ios_base::left);
935       __os.fill(__space);
936 
937       __os << __x.min() << __space << __x.max();
938 
939       __os.flags(__flags);
940       __os.fill(__fill);
941       return __os;
942     }
943 
944   template<typename _IntType, typename _CharT, typename _Traits>
945     std::basic_istream<_CharT, _Traits>&
946     operator>>(std::basic_istream<_CharT, _Traits>& __is,
947 	       uniform_int<_IntType>& __x)
948     {
949       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
950       typedef typename __istream_type::ios_base    __ios_base;
951 
952       const typename __ios_base::fmtflags __flags = __is.flags();
953       __is.flags(__ios_base::dec | __ios_base::skipws);
954 
955       __is >> __x._M_min >> __x._M_max;
956 
957       __is.flags(__flags);
958       return __is;
959     }
960 
961 
962   template<typename _CharT, typename _Traits>
963     std::basic_ostream<_CharT, _Traits>&
964     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
965 	       const bernoulli_distribution& __x)
966     {
967       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
968       typedef typename __ostream_type::ios_base    __ios_base;
969 
970       const typename __ios_base::fmtflags __flags = __os.flags();
971       const _CharT __fill = __os.fill();
972       const std::streamsize __precision = __os.precision();
973       __os.flags(__ios_base::scientific | __ios_base::left);
974       __os.fill(__os.widen(' '));
975       __os.precision(__gnu_cxx::__numeric_traits<double>::__max_digits10);
976 
977       __os << __x.p();
978 
979       __os.flags(__flags);
980       __os.fill(__fill);
981       __os.precision(__precision);
982       return __os;
983     }
984 
985 
986   template<typename _IntType, typename _RealType>
987     template<class _UniformRandomNumberGenerator>
988       typename geometric_distribution<_IntType, _RealType>::result_type
989       geometric_distribution<_IntType, _RealType>::
990       operator()(_UniformRandomNumberGenerator& __urng)
991       {
992 	// About the epsilon thing see this thread:
993         // http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00971.html
994 	const _RealType __naf =
995 	  (1 - std::numeric_limits<_RealType>::epsilon()) / 2;
996 	// The largest _RealType convertible to _IntType.
997 	const _RealType __thr =
998 	  std::numeric_limits<_IntType>::max() + __naf;
999 
1000 	_RealType __cand;
1001 	do
1002 	  __cand = std::ceil(std::log(__urng()) / _M_log_p);
1003 	while (__cand >= __thr);
1004 
1005 	return result_type(__cand + __naf);
1006       }
1007 
1008   template<typename _IntType, typename _RealType,
1009 	   typename _CharT, typename _Traits>
1010     std::basic_ostream<_CharT, _Traits>&
1011     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1012 	       const geometric_distribution<_IntType, _RealType>& __x)
1013     {
1014       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1015       typedef typename __ostream_type::ios_base    __ios_base;
1016 
1017       const typename __ios_base::fmtflags __flags = __os.flags();
1018       const _CharT __fill = __os.fill();
1019       const std::streamsize __precision = __os.precision();
1020       __os.flags(__ios_base::scientific | __ios_base::left);
1021       __os.fill(__os.widen(' '));
1022       __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1023 
1024       __os << __x.p();
1025 
1026       __os.flags(__flags);
1027       __os.fill(__fill);
1028       __os.precision(__precision);
1029       return __os;
1030     }
1031 
1032 
1033   template<typename _IntType, typename _RealType>
1034     void
1035     poisson_distribution<_IntType, _RealType>::
1036     _M_initialize()
1037     {
1038 #if _GLIBCXX_USE_C99_MATH_TR1
1039       if (_M_mean >= 12)
1040 	{
1041 	  const _RealType __m = std::floor(_M_mean);
1042 	  _M_lm_thr = std::log(_M_mean);
1043 	  _M_lfm = std::tr1::lgamma(__m + 1);
1044 	  _M_sm = std::sqrt(__m);
1045 
1046 	  const _RealType __pi_4 = 0.7853981633974483096156608458198757L;
1047 	  const _RealType __dx = std::sqrt(2 * __m * std::log(32 * __m
1048 							      / __pi_4));
1049 	  _M_d = std::tr1::round(std::max(_RealType(6),
1050 					  std::min(__m, __dx)));
1051 	  const _RealType __cx = 2 * __m + _M_d;
1052 	  _M_scx = std::sqrt(__cx / 2);
1053 	  _M_1cx = 1 / __cx;
1054 
1055 	  _M_c2b = std::sqrt(__pi_4 * __cx) * std::exp(_M_1cx);
1056 	  _M_cb = 2 * __cx * std::exp(-_M_d * _M_1cx * (1 + _M_d / 2)) / _M_d;
1057 	}
1058       else
1059 #endif
1060 	_M_lm_thr = std::exp(-_M_mean);
1061       }
1062 
1063   /**
1064    * A rejection algorithm when mean >= 12 and a simple method based
1065    * upon the multiplication of uniform random variates otherwise.
1066    * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
1067    * is defined.
1068    *
1069    * Reference:
1070    * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1071    * New York, 1986, Ch. X, Sects. 3.3 & 3.4 (+ Errata!).
1072    */
1073   template<typename _IntType, typename _RealType>
1074     template<class _UniformRandomNumberGenerator>
1075       typename poisson_distribution<_IntType, _RealType>::result_type
1076       poisson_distribution<_IntType, _RealType>::
1077       operator()(_UniformRandomNumberGenerator& __urng)
1078       {
1079 #if _GLIBCXX_USE_C99_MATH_TR1
1080 	if (_M_mean >= 12)
1081 	  {
1082 	    _RealType __x;
1083 
1084 	    // See comments above...
1085 	    const _RealType __naf =
1086 	      (1 - std::numeric_limits<_RealType>::epsilon()) / 2;
1087 	    const _RealType __thr =
1088 	      std::numeric_limits<_IntType>::max() + __naf;
1089 
1090 	    const _RealType __m = std::floor(_M_mean);
1091 	    // sqrt(pi / 2)
1092 	    const _RealType __spi_2 = 1.2533141373155002512078826424055226L;
1093 	    const _RealType __c1 = _M_sm * __spi_2;
1094 	    const _RealType __c2 = _M_c2b + __c1;
1095 	    const _RealType __c3 = __c2 + 1;
1096 	    const _RealType __c4 = __c3 + 1;
1097 	    // e^(1 / 78)
1098 	    const _RealType __e178 = 1.0129030479320018583185514777512983L;
1099 	    const _RealType __c5 = __c4 + __e178;
1100 	    const _RealType __c = _M_cb + __c5;
1101 	    const _RealType __2cx = 2 * (2 * __m + _M_d);
1102 
1103 	    bool __reject = true;
1104 	    do
1105 	      {
1106 		const _RealType __u = __c * __urng();
1107 		const _RealType __e = -std::log(__urng());
1108 
1109 		_RealType __w = 0.0;
1110 
1111 		if (__u <= __c1)
1112 		  {
1113 		    const _RealType __n = _M_nd(__urng);
1114 		    const _RealType __y = -std::abs(__n) * _M_sm - 1;
1115 		    __x = std::floor(__y);
1116 		    __w = -__n * __n / 2;
1117 		    if (__x < -__m)
1118 		      continue;
1119 		  }
1120 		else if (__u <= __c2)
1121 		  {
1122 		    const _RealType __n = _M_nd(__urng);
1123 		    const _RealType __y = 1 + std::abs(__n) * _M_scx;
1124 		    __x = std::ceil(__y);
1125 		    __w = __y * (2 - __y) * _M_1cx;
1126 		    if (__x > _M_d)
1127 		      continue;
1128 		  }
1129 		else if (__u <= __c3)
1130 		  // NB: This case not in the book, nor in the Errata,
1131 		  // but should be ok...
1132 		  __x = -1;
1133 		else if (__u <= __c4)
1134 		  __x = 0;
1135 		else if (__u <= __c5)
1136 		  __x = 1;
1137 		else
1138 		  {
1139 		    const _RealType __v = -std::log(__urng());
1140 		    const _RealType __y = _M_d + __v * __2cx / _M_d;
1141 		    __x = std::ceil(__y);
1142 		    __w = -_M_d * _M_1cx * (1 + __y / 2);
1143 		  }
1144 
1145 		__reject = (__w - __e - __x * _M_lm_thr
1146 			    > _M_lfm - std::tr1::lgamma(__x + __m + 1));
1147 
1148 		__reject |= __x + __m >= __thr;
1149 
1150 	      } while (__reject);
1151 
1152 	    return result_type(__x + __m + __naf);
1153 	  }
1154 	else
1155 #endif
1156 	  {
1157 	    _IntType     __x = 0;
1158 	    _RealType __prod = 1.0;
1159 
1160 	    do
1161 	      {
1162 		__prod *= __urng();
1163 		__x += 1;
1164 	      }
1165 	    while (__prod > _M_lm_thr);
1166 
1167 	    return __x - 1;
1168 	  }
1169       }
1170 
1171   template<typename _IntType, typename _RealType,
1172 	   typename _CharT, typename _Traits>
1173     std::basic_ostream<_CharT, _Traits>&
1174     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1175 	       const poisson_distribution<_IntType, _RealType>& __x)
1176     {
1177       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1178       typedef typename __ostream_type::ios_base    __ios_base;
1179 
1180       const typename __ios_base::fmtflags __flags = __os.flags();
1181       const _CharT __fill = __os.fill();
1182       const std::streamsize __precision = __os.precision();
1183       const _CharT __space = __os.widen(' ');
1184       __os.flags(__ios_base::scientific | __ios_base::left);
1185       __os.fill(__space);
1186       __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1187 
1188       __os << __x.mean() << __space << __x._M_nd;
1189 
1190       __os.flags(__flags);
1191       __os.fill(__fill);
1192       __os.precision(__precision);
1193       return __os;
1194     }
1195 
1196   template<typename _IntType, typename _RealType,
1197 	   typename _CharT, typename _Traits>
1198     std::basic_istream<_CharT, _Traits>&
1199     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1200 	       poisson_distribution<_IntType, _RealType>& __x)
1201     {
1202       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1203       typedef typename __istream_type::ios_base    __ios_base;
1204 
1205       const typename __ios_base::fmtflags __flags = __is.flags();
1206       __is.flags(__ios_base::skipws);
1207 
1208       __is >> __x._M_mean >> __x._M_nd;
1209       __x._M_initialize();
1210 
1211       __is.flags(__flags);
1212       return __is;
1213     }
1214 
1215 
1216   template<typename _IntType, typename _RealType>
1217     void
1218     binomial_distribution<_IntType, _RealType>::
1219     _M_initialize()
1220     {
1221       const _RealType __p12 = _M_p <= 0.5 ? _M_p : 1.0 - _M_p;
1222 
1223       _M_easy = true;
1224 
1225 #if _GLIBCXX_USE_C99_MATH_TR1
1226       if (_M_t * __p12 >= 8)
1227 	{
1228 	  _M_easy = false;
1229 	  const _RealType __np = std::floor(_M_t * __p12);
1230 	  const _RealType __pa = __np / _M_t;
1231 	  const _RealType __1p = 1 - __pa;
1232 
1233 	  const _RealType __pi_4 = 0.7853981633974483096156608458198757L;
1234 	  const _RealType __d1x =
1235 	    std::sqrt(__np * __1p * std::log(32 * __np
1236 					     / (81 * __pi_4 * __1p)));
1237 	  _M_d1 = std::tr1::round(std::max(_RealType(1), __d1x));
1238 	  const _RealType __d2x =
1239 	    std::sqrt(__np * __1p * std::log(32 * _M_t * __1p
1240 					     / (__pi_4 * __pa)));
1241 	  _M_d2 = std::tr1::round(std::max(_RealType(1), __d2x));
1242 
1243 	  // sqrt(pi / 2)
1244 	  const _RealType __spi_2 = 1.2533141373155002512078826424055226L;
1245 	  _M_s1 = std::sqrt(__np * __1p) * (1 + _M_d1 / (4 * __np));
1246 	  _M_s2 = std::sqrt(__np * __1p) * (1 + _M_d2 / (4 * _M_t * __1p));
1247 	  _M_c = 2 * _M_d1 / __np;
1248 	  _M_a1 = std::exp(_M_c) * _M_s1 * __spi_2;
1249 	  const _RealType __a12 = _M_a1 + _M_s2 * __spi_2;
1250 	  const _RealType __s1s = _M_s1 * _M_s1;
1251 	  _M_a123 = __a12 + (std::exp(_M_d1 / (_M_t * __1p))
1252 			     * 2 * __s1s / _M_d1
1253 			     * std::exp(-_M_d1 * _M_d1 / (2 * __s1s)));
1254 	  const _RealType __s2s = _M_s2 * _M_s2;
1255 	  _M_s = (_M_a123 + 2 * __s2s / _M_d2
1256 		  * std::exp(-_M_d2 * _M_d2 / (2 * __s2s)));
1257 	  _M_lf = (std::tr1::lgamma(__np + 1)
1258 		   + std::tr1::lgamma(_M_t - __np + 1));
1259 	  _M_lp1p = std::log(__pa / __1p);
1260 
1261 	  _M_q = -std::log(1 - (__p12 - __pa) / __1p);
1262 	}
1263       else
1264 #endif
1265 	_M_q = -std::log(1 - __p12);
1266     }
1267 
1268   template<typename _IntType, typename _RealType>
1269     template<class _UniformRandomNumberGenerator>
1270       typename binomial_distribution<_IntType, _RealType>::result_type
1271       binomial_distribution<_IntType, _RealType>::
1272       _M_waiting(_UniformRandomNumberGenerator& __urng, _IntType __t)
1273       {
1274 	_IntType    __x = 0;
1275 	_RealType __sum = 0;
1276 
1277 	do
1278 	  {
1279 	    const _RealType __e = -std::log(__urng());
1280 	    __sum += __e / (__t - __x);
1281 	    __x += 1;
1282 	  }
1283 	while (__sum <= _M_q);
1284 
1285 	return __x - 1;
1286       }
1287 
1288   /**
1289    * A rejection algorithm when t * p >= 8 and a simple waiting time
1290    * method - the second in the referenced book - otherwise.
1291    * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
1292    * is defined.
1293    *
1294    * Reference:
1295    * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1296    * New York, 1986, Ch. X, Sect. 4 (+ Errata!).
1297    */
1298   template<typename _IntType, typename _RealType>
1299     template<class _UniformRandomNumberGenerator>
1300       typename binomial_distribution<_IntType, _RealType>::result_type
1301       binomial_distribution<_IntType, _RealType>::
1302       operator()(_UniformRandomNumberGenerator& __urng)
1303       {
1304 	result_type __ret;
1305 	const _RealType __p12 = _M_p <= 0.5 ? _M_p : 1.0 - _M_p;
1306 
1307 #if _GLIBCXX_USE_C99_MATH_TR1
1308 	if (!_M_easy)
1309 	  {
1310 	    _RealType __x;
1311 
1312 	    // See comments above...
1313 	    const _RealType __naf =
1314 	      (1 - std::numeric_limits<_RealType>::epsilon()) / 2;
1315 	    const _RealType __thr =
1316 	      std::numeric_limits<_IntType>::max() + __naf;
1317 
1318 	    const _RealType __np = std::floor(_M_t * __p12);
1319 	    const _RealType __pa = __np / _M_t;
1320 
1321 	    // sqrt(pi / 2)
1322 	    const _RealType __spi_2 = 1.2533141373155002512078826424055226L;
1323 	    const _RealType __a1 = _M_a1;
1324 	    const _RealType __a12 = __a1 + _M_s2 * __spi_2;
1325 	    const _RealType __a123 = _M_a123;
1326 	    const _RealType __s1s = _M_s1 * _M_s1;
1327 	    const _RealType __s2s = _M_s2 * _M_s2;
1328 
1329 	    bool __reject;
1330 	    do
1331 	      {
1332 		const _RealType __u = _M_s * __urng();
1333 
1334 		_RealType __v;
1335 
1336 		if (__u <= __a1)
1337 		  {
1338 		    const _RealType __n = _M_nd(__urng);
1339 		    const _RealType __y = _M_s1 * std::abs(__n);
1340 		    __reject = __y >= _M_d1;
1341 		    if (!__reject)
1342 		      {
1343 			const _RealType __e = -std::log(__urng());
1344 			__x = std::floor(__y);
1345 			__v = -__e - __n * __n / 2 + _M_c;
1346 		      }
1347 		  }
1348 		else if (__u <= __a12)
1349 		  {
1350 		    const _RealType __n = _M_nd(__urng);
1351 		    const _RealType __y = _M_s2 * std::abs(__n);
1352 		    __reject = __y >= _M_d2;
1353 		    if (!__reject)
1354 		      {
1355 			const _RealType __e = -std::log(__urng());
1356 			__x = std::floor(-__y);
1357 			__v = -__e - __n * __n / 2;
1358 		      }
1359 		  }
1360 		else if (__u <= __a123)
1361 		  {
1362 		    const _RealType __e1 = -std::log(__urng());
1363 		    const _RealType __e2 = -std::log(__urng());
1364 
1365 		    const _RealType __y = _M_d1 + 2 * __s1s * __e1 / _M_d1;
1366 		    __x = std::floor(__y);
1367 		    __v = (-__e2 + _M_d1 * (1 / (_M_t - __np)
1368 					    -__y / (2 * __s1s)));
1369 		    __reject = false;
1370 		  }
1371 		else
1372 		  {
1373 		    const _RealType __e1 = -std::log(__urng());
1374 		    const _RealType __e2 = -std::log(__urng());
1375 
1376 		    const _RealType __y = _M_d2 + 2 * __s2s * __e1 / _M_d2;
1377 		    __x = std::floor(-__y);
1378 		    __v = -__e2 - _M_d2 * __y / (2 * __s2s);
1379 		    __reject = false;
1380 		  }
1381 
1382 		__reject = __reject || __x < -__np || __x > _M_t - __np;
1383 		if (!__reject)
1384 		  {
1385 		    const _RealType __lfx =
1386 		      std::tr1::lgamma(__np + __x + 1)
1387 		      + std::tr1::lgamma(_M_t - (__np + __x) + 1);
1388 		    __reject = __v > _M_lf - __lfx + __x * _M_lp1p;
1389 		  }
1390 
1391 		__reject |= __x + __np >= __thr;
1392 	      }
1393 	    while (__reject);
1394 
1395 	    __x += __np + __naf;
1396 
1397 	    const _IntType __z = _M_waiting(__urng, _M_t - _IntType(__x));
1398 	    __ret = _IntType(__x) + __z;
1399 	  }
1400 	else
1401 #endif
1402 	  __ret = _M_waiting(__urng, _M_t);
1403 
1404 	if (__p12 != _M_p)
1405 	  __ret = _M_t - __ret;
1406 	return __ret;
1407       }
1408 
1409   template<typename _IntType, typename _RealType,
1410 	   typename _CharT, typename _Traits>
1411     std::basic_ostream<_CharT, _Traits>&
1412     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1413 	       const binomial_distribution<_IntType, _RealType>& __x)
1414     {
1415       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1416       typedef typename __ostream_type::ios_base    __ios_base;
1417 
1418       const typename __ios_base::fmtflags __flags = __os.flags();
1419       const _CharT __fill = __os.fill();
1420       const std::streamsize __precision = __os.precision();
1421       const _CharT __space = __os.widen(' ');
1422       __os.flags(__ios_base::scientific | __ios_base::left);
1423       __os.fill(__space);
1424       __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1425 
1426       __os << __x.t() << __space << __x.p()
1427 	   << __space << __x._M_nd;
1428 
1429       __os.flags(__flags);
1430       __os.fill(__fill);
1431       __os.precision(__precision);
1432       return __os;
1433     }
1434 
1435   template<typename _IntType, typename _RealType,
1436 	   typename _CharT, typename _Traits>
1437     std::basic_istream<_CharT, _Traits>&
1438     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1439 	       binomial_distribution<_IntType, _RealType>& __x)
1440     {
1441       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1442       typedef typename __istream_type::ios_base    __ios_base;
1443 
1444       const typename __ios_base::fmtflags __flags = __is.flags();
1445       __is.flags(__ios_base::dec | __ios_base::skipws);
1446 
1447       __is >> __x._M_t >> __x._M_p >> __x._M_nd;
1448       __x._M_initialize();
1449 
1450       __is.flags(__flags);
1451       return __is;
1452     }
1453 
1454 
1455   template<typename _RealType, typename _CharT, typename _Traits>
1456     std::basic_ostream<_CharT, _Traits>&
1457     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1458 	       const uniform_real<_RealType>& __x)
1459     {
1460       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1461       typedef typename __ostream_type::ios_base    __ios_base;
1462 
1463       const typename __ios_base::fmtflags __flags = __os.flags();
1464       const _CharT __fill = __os.fill();
1465       const std::streamsize __precision = __os.precision();
1466       const _CharT __space = __os.widen(' ');
1467       __os.flags(__ios_base::scientific | __ios_base::left);
1468       __os.fill(__space);
1469       __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1470 
1471       __os << __x.min() << __space << __x.max();
1472 
1473       __os.flags(__flags);
1474       __os.fill(__fill);
1475       __os.precision(__precision);
1476       return __os;
1477     }
1478 
1479   template<typename _RealType, typename _CharT, typename _Traits>
1480     std::basic_istream<_CharT, _Traits>&
1481     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1482 	       uniform_real<_RealType>& __x)
1483     {
1484       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1485       typedef typename __istream_type::ios_base    __ios_base;
1486 
1487       const typename __ios_base::fmtflags __flags = __is.flags();
1488       __is.flags(__ios_base::skipws);
1489 
1490       __is >> __x._M_min >> __x._M_max;
1491 
1492       __is.flags(__flags);
1493       return __is;
1494     }
1495 
1496 
1497   template<typename _RealType, typename _CharT, typename _Traits>
1498     std::basic_ostream<_CharT, _Traits>&
1499     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1500 	       const exponential_distribution<_RealType>& __x)
1501     {
1502       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1503       typedef typename __ostream_type::ios_base    __ios_base;
1504 
1505       const typename __ios_base::fmtflags __flags = __os.flags();
1506       const _CharT __fill = __os.fill();
1507       const std::streamsize __precision = __os.precision();
1508       __os.flags(__ios_base::scientific | __ios_base::left);
1509       __os.fill(__os.widen(' '));
1510       __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1511 
1512       __os << __x.lambda();
1513 
1514       __os.flags(__flags);
1515       __os.fill(__fill);
1516       __os.precision(__precision);
1517       return __os;
1518     }
1519 
1520 
1521   /**
1522    * Polar method due to Marsaglia.
1523    *
1524    * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1525    * New York, 1986, Ch. V, Sect. 4.4.
1526    */
1527   template<typename _RealType>
1528     template<class _UniformRandomNumberGenerator>
1529       typename normal_distribution<_RealType>::result_type
1530       normal_distribution<_RealType>::
1531       operator()(_UniformRandomNumberGenerator& __urng)
1532       {
1533 	result_type __ret;
1534 
1535 	if (_M_saved_available)
1536 	  {
1537 	    _M_saved_available = false;
1538 	    __ret = _M_saved;
1539 	  }
1540 	else
1541 	  {
1542 	    result_type __x, __y, __r2;
1543 	    do
1544 	      {
1545 		__x = result_type(2.0) * __urng() - 1.0;
1546 		__y = result_type(2.0) * __urng() - 1.0;
1547 		__r2 = __x * __x + __y * __y;
1548 	      }
1549 	    while (__r2 > 1.0 || __r2 == 0.0);
1550 
1551 	    const result_type __mult = std::sqrt(-2 * std::log(__r2) / __r2);
1552 	    _M_saved = __x * __mult;
1553 	    _M_saved_available = true;
1554 	    __ret = __y * __mult;
1555 	  }
1556 
1557 	__ret = __ret * _M_sigma + _M_mean;
1558 	return __ret;
1559       }
1560 
1561   template<typename _RealType, typename _CharT, typename _Traits>
1562     std::basic_ostream<_CharT, _Traits>&
1563     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1564 	       const normal_distribution<_RealType>& __x)
1565     {
1566       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1567       typedef typename __ostream_type::ios_base    __ios_base;
1568 
1569       const typename __ios_base::fmtflags __flags = __os.flags();
1570       const _CharT __fill = __os.fill();
1571       const std::streamsize __precision = __os.precision();
1572       const _CharT __space = __os.widen(' ');
1573       __os.flags(__ios_base::scientific | __ios_base::left);
1574       __os.fill(__space);
1575       __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1576 
1577       __os << __x._M_saved_available << __space
1578 	   << __x.mean() << __space
1579 	   << __x.sigma();
1580       if (__x._M_saved_available)
1581 	__os << __space << __x._M_saved;
1582 
1583       __os.flags(__flags);
1584       __os.fill(__fill);
1585       __os.precision(__precision);
1586       return __os;
1587     }
1588 
1589   template<typename _RealType, typename _CharT, typename _Traits>
1590     std::basic_istream<_CharT, _Traits>&
1591     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1592 	       normal_distribution<_RealType>& __x)
1593     {
1594       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1595       typedef typename __istream_type::ios_base    __ios_base;
1596 
1597       const typename __ios_base::fmtflags __flags = __is.flags();
1598       __is.flags(__ios_base::dec | __ios_base::skipws);
1599 
1600       __is >> __x._M_saved_available >> __x._M_mean
1601 	   >> __x._M_sigma;
1602       if (__x._M_saved_available)
1603 	__is >> __x._M_saved;
1604 
1605       __is.flags(__flags);
1606       return __is;
1607     }
1608 
1609 
1610   template<typename _RealType>
1611     void
1612     gamma_distribution<_RealType>::
1613     _M_initialize()
1614     {
1615       if (_M_alpha >= 1)
1616 	_M_l_d = std::sqrt(2 * _M_alpha - 1);
1617       else
1618 	_M_l_d = (std::pow(_M_alpha, _M_alpha / (1 - _M_alpha))
1619 		  * (1 - _M_alpha));
1620     }
1621 
1622   /**
1623    * Cheng's rejection algorithm GB for alpha >= 1 and a modification
1624    * of Vaduva's rejection from Weibull algorithm due to Devroye for
1625    * alpha < 1.
1626    *
1627    * References:
1628    * Cheng, R. C. The Generation of Gamma Random Variables with Non-integral
1629    * Shape Parameter. Applied Statistics, 26, 71-75, 1977.
1630    *
1631    * Vaduva, I. Computer Generation of Gamma Gandom Variables by Rejection
1632    * and Composition Procedures. Math. Operationsforschung and Statistik,
1633    * Series in Statistics, 8, 545-576, 1977.
1634    *
1635    * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1636    * New York, 1986, Ch. IX, Sect. 3.4 (+ Errata!).
1637    */
1638   template<typename _RealType>
1639     template<class _UniformRandomNumberGenerator>
1640       typename gamma_distribution<_RealType>::result_type
1641       gamma_distribution<_RealType>::
1642       operator()(_UniformRandomNumberGenerator& __urng)
1643       {
1644 	result_type __x;
1645 
1646 	bool __reject;
1647 	if (_M_alpha >= 1)
1648 	  {
1649 	    // alpha - log(4)
1650 	    const result_type __b = _M_alpha
1651 	      - result_type(1.3862943611198906188344642429163531L);
1652 	    const result_type __c = _M_alpha + _M_l_d;
1653 	    const result_type __1l = 1 / _M_l_d;
1654 
1655 	    // 1 + log(9 / 2)
1656 	    const result_type __k = 2.5040773967762740733732583523868748L;
1657 
1658 	    do
1659 	      {
1660 		const result_type __u = __urng();
1661 		const result_type __v = __urng();
1662 
1663 		const result_type __y = __1l * std::log(__v / (1 - __v));
1664 		__x = _M_alpha * std::exp(__y);
1665 
1666 		const result_type __z = __u * __v * __v;
1667 		const result_type __r = __b + __c * __y - __x;
1668 
1669 		__reject = __r < result_type(4.5) * __z - __k;
1670 		if (__reject)
1671 		  __reject = __r < std::log(__z);
1672 	      }
1673 	    while (__reject);
1674 	  }
1675 	else
1676 	  {
1677 	    const result_type __c = 1 / _M_alpha;
1678 
1679 	    do
1680 	      {
1681 		const result_type __z = -std::log(__urng());
1682 		const result_type __e = -std::log(__urng());
1683 
1684 		__x = std::pow(__z, __c);
1685 
1686 		__reject = __z + __e < _M_l_d + __x;
1687 	      }
1688 	    while (__reject);
1689 	  }
1690 
1691 	return __x;
1692       }
1693 
1694   template<typename _RealType, typename _CharT, typename _Traits>
1695     std::basic_ostream<_CharT, _Traits>&
1696     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1697 	       const gamma_distribution<_RealType>& __x)
1698     {
1699       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1700       typedef typename __ostream_type::ios_base    __ios_base;
1701 
1702       const typename __ios_base::fmtflags __flags = __os.flags();
1703       const _CharT __fill = __os.fill();
1704       const std::streamsize __precision = __os.precision();
1705       __os.flags(__ios_base::scientific | __ios_base::left);
1706       __os.fill(__os.widen(' '));
1707       __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1708 
1709       __os << __x.alpha();
1710 
1711       __os.flags(__flags);
1712       __os.fill(__fill);
1713       __os.precision(__precision);
1714       return __os;
1715     }
1716 
1717 _GLIBCXX_END_NAMESPACE_VERSION
1718 }
1719 }
1720 
1721 #endif
1722