1// random number generation (out of line) -*- C++ -*-
2
3// Copyright (C) 2009-2022 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
34namespace std _GLIBCXX_VISIBILITY(default)
35{
36_GLIBCXX_BEGIN_NAMESPACE_VERSION
37
38namespace tr1
39{
40  /*
41   * (Further) implementation-space details.
42   */
43  namespace __detail
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  } // namespace __detail
96
97  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
98    const _UIntType
99    linear_congruential<_UIntType, __a, __c, __m>::multiplier;
100
101  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
102    const _UIntType
103    linear_congruential<_UIntType, __a, __c, __m>::increment;
104
105  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
106    const _UIntType
107    linear_congruential<_UIntType, __a, __c, __m>::modulus;
108
109  /**
110   * Seeds the LCR with integral value @p __x0, adjusted so that the 
111   * ring identity is never a member of the convergence set.
112   */
113  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
114    void
115    linear_congruential<_UIntType, __a, __c, __m>::
116    seed(unsigned long __x0)
117    {
118      if ((__detail::__mod<_UIntType, 1, 0, __m>(__c) == 0)
119	  && (__detail::__mod<_UIntType, 1, 0, __m>(__x0) == 0))
120	_M_x = __detail::__mod<_UIntType, 1, 0, __m>(1);
121      else
122	_M_x = __detail::__mod<_UIntType, 1, 0, __m>(__x0);
123    }
124
125  /**
126   * Seeds the LCR engine with a value generated by @p __g.
127   */
128  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
129    template<class _Gen>
130      void
131      linear_congruential<_UIntType, __a, __c, __m>::
132      seed(_Gen& __g, false_type)
133      {
134	_UIntType __x0 = __g();
135	if ((__detail::__mod<_UIntType, 1, 0, __m>(__c) == 0)
136	    && (__detail::__mod<_UIntType, 1, 0, __m>(__x0) == 0))
137	  _M_x = __detail::__mod<_UIntType, 1, 0, __m>(1);
138	else
139	  _M_x = __detail::__mod<_UIntType, 1, 0, __m>(__x0);
140      }
141
142  /**
143   * Gets the next generated value in sequence.
144   */
145  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
146    typename linear_congruential<_UIntType, __a, __c, __m>::result_type
147    linear_congruential<_UIntType, __a, __c, __m>::
148    operator()()
149    {
150      _M_x = __detail::__mod<_UIntType, __a, __c, __m>(_M_x);
151      return _M_x;
152    }
153
154  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
155	   typename _CharT, typename _Traits>
156    std::basic_ostream<_CharT, _Traits>&
157    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
158	       const linear_congruential<_UIntType, __a, __c, __m>& __lcr)
159    {
160      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
161      typedef typename __ostream_type::ios_base    __ios_base;
162
163      const typename __ios_base::fmtflags __flags = __os.flags();
164      const _CharT __fill = __os.fill();
165      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
166      __os.fill(__os.widen(' '));
167
168      __os << __lcr._M_x;
169
170      __os.flags(__flags);
171      __os.fill(__fill);
172      return __os;
173    }
174
175  template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
176	   typename _CharT, typename _Traits>
177    std::basic_istream<_CharT, _Traits>&
178    operator>>(std::basic_istream<_CharT, _Traits>& __is,
179	       linear_congruential<_UIntType, __a, __c, __m>& __lcr)
180    {
181      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
182      typedef typename __istream_type::ios_base    __ios_base;
183
184      const typename __ios_base::fmtflags __flags = __is.flags();
185      __is.flags(__ios_base::dec);
186
187      __is >> __lcr._M_x;
188
189      __is.flags(__flags);
190      return __is;
191    } 
192
193
194  template<class _UIntType, int __w, int __n, int __m, int __r,
195	   _UIntType __a, int __u, int __s,
196	   _UIntType __b, int __t, _UIntType __c, int __l>
197    const int
198    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
199		     __b, __t, __c, __l>::word_size;
200
201  template<class _UIntType, int __w, int __n, int __m, int __r,
202	   _UIntType __a, int __u, int __s,
203	   _UIntType __b, int __t, _UIntType __c, int __l>
204    const int
205    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
206		     __b, __t, __c, __l>::state_size;
207    
208  template<class _UIntType, int __w, int __n, int __m, int __r,
209	   _UIntType __a, int __u, int __s,
210	   _UIntType __b, int __t, _UIntType __c, int __l>
211    const int
212    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
213		     __b, __t, __c, __l>::shift_size;
214
215  template<class _UIntType, int __w, int __n, int __m, int __r,
216	   _UIntType __a, int __u, int __s,
217	   _UIntType __b, int __t, _UIntType __c, int __l>
218    const int
219    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
220		     __b, __t, __c, __l>::mask_bits;
221
222  template<class _UIntType, int __w, int __n, int __m, int __r,
223	   _UIntType __a, int __u, int __s,
224	   _UIntType __b, int __t, _UIntType __c, int __l>
225    const _UIntType
226    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
227		     __b, __t, __c, __l>::parameter_a;
228
229  template<class _UIntType, int __w, int __n, int __m, int __r,
230	   _UIntType __a, int __u, int __s,
231	   _UIntType __b, int __t, _UIntType __c, int __l>
232    const int
233    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
234		     __b, __t, __c, __l>::output_u;
235
236  template<class _UIntType, int __w, int __n, int __m, int __r,
237	   _UIntType __a, int __u, int __s,
238	   _UIntType __b, int __t, _UIntType __c, int __l>
239    const int
240    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
241		     __b, __t, __c, __l>::output_s;
242
243  template<class _UIntType, int __w, int __n, int __m, int __r,
244	   _UIntType __a, int __u, int __s,
245	   _UIntType __b, int __t, _UIntType __c, int __l>
246    const _UIntType
247    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
248		     __b, __t, __c, __l>::output_b;
249
250  template<class _UIntType, int __w, int __n, int __m, int __r,
251	   _UIntType __a, int __u, int __s,
252	   _UIntType __b, int __t, _UIntType __c, int __l>
253    const int
254    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
255		     __b, __t, __c, __l>::output_t;
256
257  template<class _UIntType, int __w, int __n, int __m, int __r,
258	   _UIntType __a, int __u, int __s,
259	   _UIntType __b, int __t, _UIntType __c, int __l>
260    const _UIntType
261    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
262		     __b, __t, __c, __l>::output_c;
263
264  template<class _UIntType, int __w, int __n, int __m, int __r,
265	   _UIntType __a, int __u, int __s,
266	   _UIntType __b, int __t, _UIntType __c, int __l>
267    const int
268    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
269		     __b, __t, __c, __l>::output_l;
270
271  template<class _UIntType, int __w, int __n, int __m, int __r,
272	   _UIntType __a, int __u, int __s,
273	   _UIntType __b, int __t, _UIntType __c, int __l>
274    void
275    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
276		     __b, __t, __c, __l>::
277    seed(unsigned long __value)
278    {
279      _M_x[0] = __detail::__mod<_UIntType, 1, 0,
280	__detail::_Shift<_UIntType, __w>::__value>(__value);
281
282      for (int __i = 1; __i < state_size; ++__i)
283	{
284	  _UIntType __x = _M_x[__i - 1];
285	  __x ^= __x >> (__w - 2);
286	  __x *= 1812433253ul;
287	  __x += __i;
288	  _M_x[__i] = __detail::__mod<_UIntType, 1, 0,
289	    __detail::_Shift<_UIntType, __w>::__value>(__x);	  
290	}
291      _M_p = state_size;
292    }
293
294  template<class _UIntType, int __w, int __n, int __m, int __r,
295	   _UIntType __a, int __u, int __s,
296	   _UIntType __b, int __t, _UIntType __c, int __l>
297    template<class _Gen>
298      void
299      mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
300		       __b, __t, __c, __l>::
301      seed(_Gen& __gen, false_type)
302      {
303	for (int __i = 0; __i < state_size; ++__i)
304	  _M_x[__i] = __detail::__mod<_UIntType, 1, 0,
305	    __detail::_Shift<_UIntType, __w>::__value>(__gen());
306	_M_p = state_size;
307      }
308
309  template<class _UIntType, int __w, int __n, int __m, int __r,
310	   _UIntType __a, int __u, int __s,
311	   _UIntType __b, int __t, _UIntType __c, int __l>
312    typename
313    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
314		     __b, __t, __c, __l>::result_type
315    mersenne_twister<_UIntType, __w, __n, __m, __r, __a, __u, __s,
316		     __b, __t, __c, __l>::
317    operator()()
318    {
319      // Reload the vector - cost is O(n) amortized over n calls.
320      if (_M_p >= state_size)
321	{
322	  const _UIntType __upper_mask = (~_UIntType()) << __r;
323	  const _UIntType __lower_mask = ~__upper_mask;
324
325	  for (int __k = 0; __k < (__n - __m); ++__k)
326	    {
327	      _UIntType __y = ((_M_x[__k] & __upper_mask)
328			       | (_M_x[__k + 1] & __lower_mask));
329	      _M_x[__k] = (_M_x[__k + __m] ^ (__y >> 1)
330			   ^ ((__y & 0x01) ? __a : 0));
331	    }
332
333	  for (int __k = (__n - __m); __k < (__n - 1); ++__k)
334	    {
335	      _UIntType __y = ((_M_x[__k] & __upper_mask)
336			       | (_M_x[__k + 1] & __lower_mask));
337	      _M_x[__k] = (_M_x[__k + (__m - __n)] ^ (__y >> 1)
338			   ^ ((__y & 0x01) ? __a : 0));
339	    }
340
341	  _UIntType __y = ((_M_x[__n - 1] & __upper_mask)
342			   | (_M_x[0] & __lower_mask));
343	  _M_x[__n - 1] = (_M_x[__m - 1] ^ (__y >> 1)
344			   ^ ((__y & 0x01) ? __a : 0));
345	  _M_p = 0;
346	}
347
348      // Calculate o(x(i)).
349      result_type __z = _M_x[_M_p++];
350      __z ^= (__z >> __u);
351      __z ^= (__z << __s) & __b;
352      __z ^= (__z << __t) & __c;
353      __z ^= (__z >> __l);
354
355      return __z;
356    }
357
358  template<class _UIntType, int __w, int __n, int __m, int __r,
359	   _UIntType __a, int __u, int __s, _UIntType __b, int __t,
360	   _UIntType __c, int __l,
361	   typename _CharT, typename _Traits>
362    std::basic_ostream<_CharT, _Traits>&
363    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
364	       const mersenne_twister<_UIntType, __w, __n, __m,
365	       __r, __a, __u, __s, __b, __t, __c, __l>& __x)
366    {
367      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
368      typedef typename __ostream_type::ios_base    __ios_base;
369
370      const typename __ios_base::fmtflags __flags = __os.flags();
371      const _CharT __fill = __os.fill();
372      const _CharT __space = __os.widen(' ');
373      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
374      __os.fill(__space);
375
376      for (int __i = 0; __i < __n - 1; ++__i)
377	__os << __x._M_x[__i] << __space;
378      __os << __x._M_x[__n - 1];
379
380      __os.flags(__flags);
381      __os.fill(__fill);
382      return __os;
383    }
384
385  template<class _UIntType, int __w, int __n, int __m, int __r,
386	   _UIntType __a, int __u, int __s, _UIntType __b, int __t,
387	   _UIntType __c, int __l,
388	   typename _CharT, typename _Traits>
389    std::basic_istream<_CharT, _Traits>&
390    operator>>(std::basic_istream<_CharT, _Traits>& __is,
391	       mersenne_twister<_UIntType, __w, __n, __m,
392	       __r, __a, __u, __s, __b, __t, __c, __l>& __x)
393    {
394      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
395      typedef typename __istream_type::ios_base    __ios_base;
396
397      const typename __ios_base::fmtflags __flags = __is.flags();
398      __is.flags(__ios_base::dec | __ios_base::skipws);
399
400      for (int __i = 0; __i < __n; ++__i)
401	__is >> __x._M_x[__i];
402
403      __is.flags(__flags);
404      return __is;
405    }
406
407
408  template<typename _IntType, _IntType __m, int __s, int __r>
409    const _IntType
410    subtract_with_carry<_IntType, __m, __s, __r>::modulus;
411
412  template<typename _IntType, _IntType __m, int __s, int __r>
413    const int
414    subtract_with_carry<_IntType, __m, __s, __r>::long_lag;
415
416  template<typename _IntType, _IntType __m, int __s, int __r>
417    const int
418    subtract_with_carry<_IntType, __m, __s, __r>::short_lag;
419
420  template<typename _IntType, _IntType __m, int __s, int __r>
421    void
422    subtract_with_carry<_IntType, __m, __s, __r>::
423    seed(unsigned long __value)
424    {
425      if (__value == 0)
426	__value = 19780503;
427
428      std::tr1::linear_congruential<unsigned long, 40014, 0, 2147483563>
429	__lcg(__value);
430
431      for (int __i = 0; __i < long_lag; ++__i)
432	_M_x[__i] = __detail::__mod<_UIntType, 1, 0, modulus>(__lcg());
433
434      _M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
435      _M_p = 0;
436    }
437
438  template<typename _IntType, _IntType __m, int __s, int __r>
439    template<class _Gen>
440      void
441      subtract_with_carry<_IntType, __m, __s, __r>::
442      seed(_Gen& __gen, false_type)
443      {
444	const int __n = (std::numeric_limits<_UIntType>::digits + 31) / 32;
445
446	for (int __i = 0; __i < long_lag; ++__i)
447	  {
448	    _UIntType __tmp = 0;
449	    _UIntType __factor = 1;
450	    for (int __j = 0; __j < __n; ++__j)
451	      {
452		__tmp += __detail::__mod<__detail::_UInt32Type, 1, 0, 0>
453		         (__gen()) * __factor;
454		__factor *= __detail::_Shift<_UIntType, 32>::__value;
455	      }
456	    _M_x[__i] = __detail::__mod<_UIntType, 1, 0, modulus>(__tmp);
457	  }
458	_M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
459	_M_p = 0;
460      }
461
462  template<typename _IntType, _IntType __m, int __s, int __r>
463    typename subtract_with_carry<_IntType, __m, __s, __r>::result_type
464    subtract_with_carry<_IntType, __m, __s, __r>::
465    operator()()
466    {
467      // Derive short lag index from current index.
468      int __ps = _M_p - short_lag;
469      if (__ps < 0)
470	__ps += long_lag;
471
472      // Calculate new x(i) without overflow or division.
473      // NB: Thanks to the requirements for _IntType, _M_x[_M_p] + _M_carry
474      // cannot overflow.
475      _UIntType __xi;
476      if (_M_x[__ps] >= _M_x[_M_p] + _M_carry)
477	{
478	  __xi = _M_x[__ps] - _M_x[_M_p] - _M_carry;
479	  _M_carry = 0;
480	}
481      else
482	{
483	  __xi = modulus - _M_x[_M_p] - _M_carry + _M_x[__ps];
484	  _M_carry = 1;
485	}
486      _M_x[_M_p] = __xi;
487
488      // Adjust current index to loop around in ring buffer.
489      if (++_M_p >= long_lag)
490	_M_p = 0;
491
492      return __xi;
493    }
494
495  template<typename _IntType, _IntType __m, int __s, int __r,
496	   typename _CharT, typename _Traits>
497    std::basic_ostream<_CharT, _Traits>&
498    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
499	       const subtract_with_carry<_IntType, __m, __s, __r>& __x)
500    {
501      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
502      typedef typename __ostream_type::ios_base    __ios_base;
503
504      const typename __ios_base::fmtflags __flags = __os.flags();
505      const _CharT __fill = __os.fill();
506      const _CharT __space = __os.widen(' ');
507      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
508      __os.fill(__space);
509
510      for (int __i = 0; __i < __r; ++__i)
511	__os << __x._M_x[__i] << __space;
512      __os << __x._M_carry;
513
514      __os.flags(__flags);
515      __os.fill(__fill);
516      return __os;
517    }
518
519  template<typename _IntType, _IntType __m, int __s, int __r,
520	   typename _CharT, typename _Traits>
521    std::basic_istream<_CharT, _Traits>&
522    operator>>(std::basic_istream<_CharT, _Traits>& __is,
523	       subtract_with_carry<_IntType, __m, __s, __r>& __x)
524    {
525      typedef std::basic_ostream<_CharT, _Traits>  __istream_type;
526      typedef typename __istream_type::ios_base    __ios_base;
527
528      const typename __ios_base::fmtflags __flags = __is.flags();
529      __is.flags(__ios_base::dec | __ios_base::skipws);
530
531      for (int __i = 0; __i < __r; ++__i)
532	__is >> __x._M_x[__i];
533      __is >> __x._M_carry;
534
535      __is.flags(__flags);
536      return __is;
537    }
538
539
540  template<typename _RealType, int __w, int __s, int __r>
541    const int
542    subtract_with_carry_01<_RealType, __w, __s, __r>::word_size;
543
544  template<typename _RealType, int __w, int __s, int __r>
545    const int
546    subtract_with_carry_01<_RealType, __w, __s, __r>::long_lag;
547
548  template<typename _RealType, int __w, int __s, int __r>
549    const int
550    subtract_with_carry_01<_RealType, __w, __s, __r>::short_lag;
551
552  template<typename _RealType, int __w, int __s, int __r>
553    void
554    subtract_with_carry_01<_RealType, __w, __s, __r>::
555    _M_initialize_npows()
556    {
557      for (int __j = 0; __j < __n; ++__j)
558#if _GLIBCXX_USE_C99_MATH_TR1
559	_M_npows[__j] = std::tr1::ldexp(_RealType(1), -__w + __j * 32);
560#else
561        _M_npows[__j] = std::pow(_RealType(2), -__w + __j * 32);
562#endif
563    }
564
565  template<typename _RealType, int __w, int __s, int __r>
566    void
567    subtract_with_carry_01<_RealType, __w, __s, __r>::
568    seed(unsigned long __value)
569    {
570      if (__value == 0)
571	__value = 19780503;
572
573      // _GLIBCXX_RESOLVE_LIB_DEFECTS
574      // 512. Seeding subtract_with_carry_01 from a single unsigned long.
575      std::tr1::linear_congruential<unsigned long, 40014, 0, 2147483563>
576	__lcg(__value);
577
578      this->seed(__lcg);
579    }
580
581  template<typename _RealType, int __w, int __s, int __r>
582    template<class _Gen>
583      void
584      subtract_with_carry_01<_RealType, __w, __s, __r>::
585      seed(_Gen& __gen, false_type)
586      {
587	for (int __i = 0; __i < long_lag; ++__i)
588	  {
589	    for (int __j = 0; __j < __n - 1; ++__j)
590	      _M_x[__i][__j] = __detail::__mod<_UInt32Type, 1, 0, 0>(__gen());
591	    _M_x[__i][__n - 1] = __detail::__mod<_UInt32Type, 1, 0,
592	      __detail::_Shift<_UInt32Type, __w % 32>::__value>(__gen());
593	  }
594
595	_M_carry = 1;
596	for (int __j = 0; __j < __n; ++__j)
597	  if (_M_x[long_lag - 1][__j] != 0)
598	    {
599	      _M_carry = 0;
600	      break;
601	    }
602
603	_M_p = 0;
604      }
605
606  template<typename _RealType, int __w, int __s, int __r>
607    typename subtract_with_carry_01<_RealType, __w, __s, __r>::result_type
608    subtract_with_carry_01<_RealType, __w, __s, __r>::
609    operator()()
610    {
611      // Derive short lag index from current index.
612      int __ps = _M_p - short_lag;
613      if (__ps < 0)
614	__ps += long_lag;
615
616      _UInt32Type __new_carry;
617      for (int __j = 0; __j < __n - 1; ++__j)
618	{
619	  if (_M_x[__ps][__j] > _M_x[_M_p][__j]
620	      || (_M_x[__ps][__j] == _M_x[_M_p][__j] && _M_carry == 0))
621	    __new_carry = 0;
622	  else
623	    __new_carry = 1;
624
625	  _M_x[_M_p][__j] = _M_x[__ps][__j] - _M_x[_M_p][__j] - _M_carry;
626	  _M_carry = __new_carry;
627	}
628
629      if (_M_x[__ps][__n - 1] > _M_x[_M_p][__n - 1]
630	  || (_M_x[__ps][__n - 1] == _M_x[_M_p][__n - 1] && _M_carry == 0))
631	__new_carry = 0;
632      else
633	__new_carry = 1;
634      
635      _M_x[_M_p][__n - 1] = __detail::__mod<_UInt32Type, 1, 0,
636	__detail::_Shift<_UInt32Type, __w % 32>::__value>
637	(_M_x[__ps][__n - 1] - _M_x[_M_p][__n - 1] - _M_carry);
638      _M_carry = __new_carry;
639
640      result_type __ret = 0.0;
641      for (int __j = 0; __j < __n; ++__j)
642	__ret += _M_x[_M_p][__j] * _M_npows[__j];
643
644      // Adjust current index to loop around in ring buffer.
645      if (++_M_p >= long_lag)
646	_M_p = 0;
647
648      return __ret;
649    }
650
651  template<typename _RealType, int __w, int __s, int __r,
652	   typename _CharT, typename _Traits>
653    std::basic_ostream<_CharT, _Traits>&
654    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
655	       const subtract_with_carry_01<_RealType, __w, __s, __r>& __x)
656    {
657      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
658      typedef typename __ostream_type::ios_base    __ios_base;
659
660      const typename __ios_base::fmtflags __flags = __os.flags();
661      const _CharT __fill = __os.fill();
662      const _CharT __space = __os.widen(' ');
663      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
664      __os.fill(__space);
665
666      for (int __i = 0; __i < __r; ++__i)
667	for (int __j = 0; __j < __x.__n; ++__j)
668	  __os << __x._M_x[__i][__j] << __space;
669      __os << __x._M_carry;
670
671      __os.flags(__flags);
672      __os.fill(__fill);
673      return __os;
674    }
675
676  template<typename _RealType, int __w, int __s, int __r,
677	   typename _CharT, typename _Traits>
678    std::basic_istream<_CharT, _Traits>&
679    operator>>(std::basic_istream<_CharT, _Traits>& __is,
680	       subtract_with_carry_01<_RealType, __w, __s, __r>& __x)
681    {
682      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
683      typedef typename __istream_type::ios_base    __ios_base;
684
685      const typename __ios_base::fmtflags __flags = __is.flags();
686      __is.flags(__ios_base::dec | __ios_base::skipws);
687
688      for (int __i = 0; __i < __r; ++__i)
689	for (int __j = 0; __j < __x.__n; ++__j)
690	  __is >> __x._M_x[__i][__j];
691      __is >> __x._M_carry;
692
693      __is.flags(__flags);
694      return __is;
695    }
696
697  template<class _UniformRandomNumberGenerator, int __p, int __r>
698    const int
699    discard_block<_UniformRandomNumberGenerator, __p, __r>::block_size;
700
701  template<class _UniformRandomNumberGenerator, int __p, int __r>
702    const int
703    discard_block<_UniformRandomNumberGenerator, __p, __r>::used_block;
704
705  template<class _UniformRandomNumberGenerator, int __p, int __r>
706    typename discard_block<_UniformRandomNumberGenerator,
707			   __p, __r>::result_type
708    discard_block<_UniformRandomNumberGenerator, __p, __r>::
709    operator()()
710    {
711      if (_M_n >= used_block)
712	{
713	  while (_M_n < block_size)
714	    {
715	      _M_b();
716	      ++_M_n;
717	    }
718	  _M_n = 0;
719	}
720      ++_M_n;
721      return _M_b();
722    }
723
724  template<class _UniformRandomNumberGenerator, int __p, int __r,
725	   typename _CharT, typename _Traits>
726    std::basic_ostream<_CharT, _Traits>&
727    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
728	       const discard_block<_UniformRandomNumberGenerator,
729	       __p, __r>& __x)
730    {
731      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
732      typedef typename __ostream_type::ios_base    __ios_base;
733
734      const typename __ios_base::fmtflags __flags = __os.flags();
735      const _CharT __fill = __os.fill();
736      const _CharT __space = __os.widen(' ');
737      __os.flags(__ios_base::dec | __ios_base::fixed
738		 | __ios_base::left);
739      __os.fill(__space);
740
741      __os << __x._M_b << __space << __x._M_n;
742
743      __os.flags(__flags);
744      __os.fill(__fill);
745      return __os;
746    }
747
748  template<class _UniformRandomNumberGenerator, int __p, int __r,
749	   typename _CharT, typename _Traits>
750    std::basic_istream<_CharT, _Traits>&
751    operator>>(std::basic_istream<_CharT, _Traits>& __is,
752	       discard_block<_UniformRandomNumberGenerator, __p, __r>& __x)
753    {
754      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
755      typedef typename __istream_type::ios_base    __ios_base;
756
757      const typename __ios_base::fmtflags __flags = __is.flags();
758      __is.flags(__ios_base::dec | __ios_base::skipws);
759
760      __is >> __x._M_b >> __x._M_n;
761
762      __is.flags(__flags);
763      return __is;
764    }
765
766
767  template<class _UniformRandomNumberGenerator1, int __s1,
768	   class _UniformRandomNumberGenerator2, int __s2>
769    const int
770    xor_combine<_UniformRandomNumberGenerator1, __s1,
771		_UniformRandomNumberGenerator2, __s2>::shift1;
772     
773  template<class _UniformRandomNumberGenerator1, int __s1,
774	   class _UniformRandomNumberGenerator2, int __s2>
775    const int
776    xor_combine<_UniformRandomNumberGenerator1, __s1,
777		_UniformRandomNumberGenerator2, __s2>::shift2;
778
779  template<class _UniformRandomNumberGenerator1, int __s1,
780	   class _UniformRandomNumberGenerator2, int __s2>
781    void
782    xor_combine<_UniformRandomNumberGenerator1, __s1,
783		_UniformRandomNumberGenerator2, __s2>::
784    _M_initialize_max()
785    {
786      const int __w = std::numeric_limits<result_type>::digits;
787
788      const result_type __m1 =
789	std::min(result_type(_M_b1.max() - _M_b1.min()),
790		 __detail::_Shift<result_type, __w - __s1>::__value - 1);
791
792      const result_type __m2 =
793	std::min(result_type(_M_b2.max() - _M_b2.min()),
794		 __detail::_Shift<result_type, __w - __s2>::__value - 1);
795
796      // NB: In TR1 s1 is not required to be >= s2.
797      if (__s1 < __s2)
798	_M_max = _M_initialize_max_aux(__m2, __m1, __s2 - __s1) << __s1;
799      else
800	_M_max = _M_initialize_max_aux(__m1, __m2, __s1 - __s2) << __s2;
801    }
802
803  template<class _UniformRandomNumberGenerator1, int __s1,
804	   class _UniformRandomNumberGenerator2, int __s2>
805    typename xor_combine<_UniformRandomNumberGenerator1, __s1,
806			 _UniformRandomNumberGenerator2, __s2>::result_type
807    xor_combine<_UniformRandomNumberGenerator1, __s1,
808		_UniformRandomNumberGenerator2, __s2>::
809    _M_initialize_max_aux(result_type __a, result_type __b, int __d)
810    {
811      const result_type __two2d = result_type(1) << __d;
812      const result_type __c = __a * __two2d;
813
814      if (__a == 0 || __b < __two2d)
815	return __c + __b;
816
817      const result_type __t = std::max(__c, __b);
818      const result_type __u = std::min(__c, __b);
819
820      result_type __ub = __u;
821      result_type __p;
822      for (__p = 0; __ub != 1; __ub >>= 1)
823	++__p;
824
825      const result_type __two2p = result_type(1) << __p;
826      const result_type __k = __t / __two2p;
827
828      if (__k & 1)
829	return (__k + 1) * __two2p - 1;
830
831      if (__c >= __b)
832	return (__k + 1) * __two2p + _M_initialize_max_aux((__t % __two2p)
833							   / __two2d,
834							   __u % __two2p, __d);
835      else
836	return (__k + 1) * __two2p + _M_initialize_max_aux((__u % __two2p)
837							   / __two2d,
838							   __t % __two2p, __d);
839    }
840
841  template<class _UniformRandomNumberGenerator1, int __s1,
842	   class _UniformRandomNumberGenerator2, int __s2,
843	   typename _CharT, typename _Traits>
844    std::basic_ostream<_CharT, _Traits>&
845    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
846	       const xor_combine<_UniformRandomNumberGenerator1, __s1,
847	       _UniformRandomNumberGenerator2, __s2>& __x)
848    {
849      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
850      typedef typename __ostream_type::ios_base    __ios_base;
851
852      const typename __ios_base::fmtflags __flags = __os.flags();
853      const _CharT __fill = __os.fill();
854      const _CharT __space = __os.widen(' ');
855      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
856      __os.fill(__space);
857
858      __os << __x.base1() << __space << __x.base2();
859
860      __os.flags(__flags);
861      __os.fill(__fill);
862      return __os; 
863    }
864
865  template<class _UniformRandomNumberGenerator1, int __s1,
866	   class _UniformRandomNumberGenerator2, int __s2,
867	   typename _CharT, typename _Traits>
868    std::basic_istream<_CharT, _Traits>&
869    operator>>(std::basic_istream<_CharT, _Traits>& __is,
870	       xor_combine<_UniformRandomNumberGenerator1, __s1,
871	       _UniformRandomNumberGenerator2, __s2>& __x)
872    {
873      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
874      typedef typename __istream_type::ios_base    __ios_base;
875
876      const typename __ios_base::fmtflags __flags = __is.flags();
877      __is.flags(__ios_base::skipws);
878
879      __is >> __x._M_b1 >> __x._M_b2;
880
881      __is.flags(__flags);
882      return __is;
883    }
884
885
886  template<typename _IntType>
887    template<typename _UniformRandomNumberGenerator>
888      typename uniform_int<_IntType>::result_type
889      uniform_int<_IntType>::
890      _M_call(_UniformRandomNumberGenerator& __urng,
891	      result_type __min, result_type __max, true_type)
892      {
893	// XXX Must be fixed to work well for *arbitrary* __urng.max(),
894	// __urng.min(), __max, __min.  Currently works fine only in the
895	// most common case __urng.max() - __urng.min() >= __max - __min,
896	// with __urng.max() > __urng.min() >= 0.
897	typedef typename __gnu_cxx::__add_unsigned<typename
898	  _UniformRandomNumberGenerator::result_type>::__type __urntype;
899	typedef typename __gnu_cxx::__add_unsigned<result_type>::__type
900	                                                      __utype;
901	typedef typename __gnu_cxx::__conditional_type<(sizeof(__urntype)
902							> sizeof(__utype)),
903	  __urntype, __utype>::__type                         __uctype;
904
905	result_type __ret;
906
907	const __urntype __urnmin = __urng.min();
908	const __urntype __urnmax = __urng.max();
909	const __urntype __urnrange = __urnmax - __urnmin;
910	const __uctype __urange = __max - __min;
911	const __uctype __udenom = (__urnrange <= __urange
912				   ? 1 : __urnrange / (__urange + 1));
913	do
914	  __ret = (__urntype(__urng()) -  __urnmin) / __udenom;
915	while (__ret > __max - __min);
916
917	return __ret + __min;
918      }
919
920  template<typename _IntType, typename _CharT, typename _Traits>
921    std::basic_ostream<_CharT, _Traits>&
922    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
923	       const uniform_int<_IntType>& __x)
924    {
925      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
926      typedef typename __ostream_type::ios_base    __ios_base;
927
928      const typename __ios_base::fmtflags __flags = __os.flags();
929      const _CharT __fill = __os.fill();
930      const _CharT __space = __os.widen(' ');
931      __os.flags(__ios_base::scientific | __ios_base::left);
932      __os.fill(__space);
933
934      __os << __x.min() << __space << __x.max();
935
936      __os.flags(__flags);
937      __os.fill(__fill);
938      return __os;
939    }
940
941  template<typename _IntType, typename _CharT, typename _Traits>
942    std::basic_istream<_CharT, _Traits>&
943    operator>>(std::basic_istream<_CharT, _Traits>& __is,
944	       uniform_int<_IntType>& __x)
945    {
946      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
947      typedef typename __istream_type::ios_base    __ios_base;
948
949      const typename __ios_base::fmtflags __flags = __is.flags();
950      __is.flags(__ios_base::dec | __ios_base::skipws);
951
952      __is >> __x._M_min >> __x._M_max;
953
954      __is.flags(__flags);
955      return __is;
956    }
957
958  
959  template<typename _CharT, typename _Traits>
960    std::basic_ostream<_CharT, _Traits>&
961    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
962	       const bernoulli_distribution& __x)
963    {
964      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
965      typedef typename __ostream_type::ios_base    __ios_base;
966
967      const typename __ios_base::fmtflags __flags = __os.flags();
968      const _CharT __fill = __os.fill();
969      const std::streamsize __precision = __os.precision();
970      __os.flags(__ios_base::scientific | __ios_base::left);
971      __os.fill(__os.widen(' '));
972      __os.precision(__gnu_cxx::__numeric_traits<double>::__max_digits10);
973
974      __os << __x.p();
975
976      __os.flags(__flags);
977      __os.fill(__fill);
978      __os.precision(__precision);
979      return __os;
980    }
981
982
983  template<typename _IntType, typename _RealType>
984    template<class _UniformRandomNumberGenerator>
985      typename geometric_distribution<_IntType, _RealType>::result_type
986      geometric_distribution<_IntType, _RealType>::
987      operator()(_UniformRandomNumberGenerator& __urng)
988      {
989	// About the epsilon thing see this thread:
990        // http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00971.html
991	const _RealType __naf =
992	  (1 - std::numeric_limits<_RealType>::epsilon()) / 2;
993	// The largest _RealType convertible to _IntType.
994	const _RealType __thr =
995	  std::numeric_limits<_IntType>::max() + __naf;
996
997	_RealType __cand;
998	do
999	  __cand = std::ceil(std::log(__urng()) / _M_log_p);
1000	while (__cand >= __thr);
1001
1002	return result_type(__cand + __naf);
1003      }
1004
1005  template<typename _IntType, typename _RealType,
1006	   typename _CharT, typename _Traits>
1007    std::basic_ostream<_CharT, _Traits>&
1008    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1009	       const geometric_distribution<_IntType, _RealType>& __x)
1010    {
1011      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1012      typedef typename __ostream_type::ios_base    __ios_base;
1013
1014      const typename __ios_base::fmtflags __flags = __os.flags();
1015      const _CharT __fill = __os.fill();
1016      const std::streamsize __precision = __os.precision();
1017      __os.flags(__ios_base::scientific | __ios_base::left);
1018      __os.fill(__os.widen(' '));
1019      __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1020
1021      __os << __x.p();
1022
1023      __os.flags(__flags);
1024      __os.fill(__fill);
1025      __os.precision(__precision);
1026      return __os;
1027    }
1028
1029
1030  template<typename _IntType, typename _RealType>
1031    void
1032    poisson_distribution<_IntType, _RealType>::
1033    _M_initialize()
1034    {
1035#if _GLIBCXX_USE_C99_MATH_TR1
1036      if (_M_mean >= 12)
1037	{
1038	  const _RealType __m = std::floor(_M_mean);
1039	  _M_lm_thr = std::log(_M_mean);
1040	  _M_lfm = std::tr1::lgamma(__m + 1);
1041	  _M_sm = std::sqrt(__m);
1042
1043	  const _RealType __pi_4 = 0.7853981633974483096156608458198757L;
1044	  const _RealType __dx = std::sqrt(2 * __m * std::log(32 * __m
1045							      / __pi_4));
1046	  _M_d = std::tr1::round(std::max(_RealType(6),
1047					  std::min(__m, __dx)));
1048	  const _RealType __cx = 2 * __m + _M_d;
1049	  _M_scx = std::sqrt(__cx / 2);
1050	  _M_1cx = 1 / __cx;
1051
1052	  _M_c2b = std::sqrt(__pi_4 * __cx) * std::exp(_M_1cx);
1053	  _M_cb = 2 * __cx * std::exp(-_M_d * _M_1cx * (1 + _M_d / 2)) / _M_d;
1054	}
1055      else
1056#endif
1057	_M_lm_thr = std::exp(-_M_mean);
1058      }
1059
1060  /**
1061   * A rejection algorithm when mean >= 12 and a simple method based
1062   * upon the multiplication of uniform random variates otherwise.
1063   * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
1064   * is defined.
1065   *
1066   * Reference:
1067   * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1068   * New York, 1986, Ch. X, Sects. 3.3 & 3.4 (+ Errata!).
1069   */
1070  template<typename _IntType, typename _RealType>
1071    template<class _UniformRandomNumberGenerator>
1072      typename poisson_distribution<_IntType, _RealType>::result_type
1073      poisson_distribution<_IntType, _RealType>::
1074      operator()(_UniformRandomNumberGenerator& __urng)
1075      {
1076#if _GLIBCXX_USE_C99_MATH_TR1
1077	if (_M_mean >= 12)
1078	  {
1079	    _RealType __x;
1080
1081	    // See comments above...
1082	    const _RealType __naf =
1083	      (1 - std::numeric_limits<_RealType>::epsilon()) / 2;
1084	    const _RealType __thr =
1085	      std::numeric_limits<_IntType>::max() + __naf;
1086
1087	    const _RealType __m = std::floor(_M_mean);
1088	    // sqrt(pi / 2)
1089	    const _RealType __spi_2 = 1.2533141373155002512078826424055226L;
1090	    const _RealType __c1 = _M_sm * __spi_2;
1091	    const _RealType __c2 = _M_c2b + __c1; 
1092	    const _RealType __c3 = __c2 + 1;
1093	    const _RealType __c4 = __c3 + 1;
1094	    // e^(1 / 78)
1095	    const _RealType __e178 = 1.0129030479320018583185514777512983L;
1096	    const _RealType __c5 = __c4 + __e178;
1097	    const _RealType __c = _M_cb + __c5;
1098	    const _RealType __2cx = 2 * (2 * __m + _M_d);
1099
1100	    bool __reject = true;
1101	    do
1102	      {
1103		const _RealType __u = __c * __urng();
1104		const _RealType __e = -std::log(__urng());
1105
1106		_RealType __w = 0.0;
1107		
1108		if (__u <= __c1)
1109		  {
1110		    const _RealType __n = _M_nd(__urng);
1111		    const _RealType __y = -std::abs(__n) * _M_sm - 1;
1112		    __x = std::floor(__y);
1113		    __w = -__n * __n / 2;
1114		    if (__x < -__m)
1115		      continue;
1116		  }
1117		else if (__u <= __c2)
1118		  {
1119		    const _RealType __n = _M_nd(__urng);
1120		    const _RealType __y = 1 + std::abs(__n) * _M_scx;
1121		    __x = std::ceil(__y);
1122		    __w = __y * (2 - __y) * _M_1cx;
1123		    if (__x > _M_d)
1124		      continue;
1125		  }
1126		else if (__u <= __c3)
1127		  // NB: This case not in the book, nor in the Errata,
1128		  // but should be ok...
1129		  __x = -1;
1130		else if (__u <= __c4)
1131		  __x = 0;
1132		else if (__u <= __c5)
1133		  __x = 1;
1134		else
1135		  {
1136		    const _RealType __v = -std::log(__urng());
1137		    const _RealType __y = _M_d + __v * __2cx / _M_d;
1138		    __x = std::ceil(__y);
1139		    __w = -_M_d * _M_1cx * (1 + __y / 2);
1140		  }
1141
1142		__reject = (__w - __e - __x * _M_lm_thr
1143			    > _M_lfm - std::tr1::lgamma(__x + __m + 1));
1144
1145		__reject |= __x + __m >= __thr;
1146
1147	      } while (__reject);
1148
1149	    return result_type(__x + __m + __naf);
1150	  }
1151	else
1152#endif
1153	  {
1154	    _IntType     __x = 0;
1155	    _RealType __prod = 1.0;
1156
1157	    do
1158	      {
1159		__prod *= __urng();
1160		__x += 1;
1161	      }
1162	    while (__prod > _M_lm_thr);
1163
1164	    return __x - 1;
1165	  }
1166      }
1167
1168  template<typename _IntType, typename _RealType,
1169	   typename _CharT, typename _Traits>
1170    std::basic_ostream<_CharT, _Traits>&
1171    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1172	       const poisson_distribution<_IntType, _RealType>& __x)
1173    {
1174      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1175      typedef typename __ostream_type::ios_base    __ios_base;
1176
1177      const typename __ios_base::fmtflags __flags = __os.flags();
1178      const _CharT __fill = __os.fill();
1179      const std::streamsize __precision = __os.precision();
1180      const _CharT __space = __os.widen(' ');
1181      __os.flags(__ios_base::scientific | __ios_base::left);
1182      __os.fill(__space);
1183      __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1184
1185      __os << __x.mean() << __space << __x._M_nd;
1186
1187      __os.flags(__flags);
1188      __os.fill(__fill);
1189      __os.precision(__precision);
1190      return __os;
1191    }
1192
1193  template<typename _IntType, typename _RealType,
1194	   typename _CharT, typename _Traits>
1195    std::basic_istream<_CharT, _Traits>&
1196    operator>>(std::basic_istream<_CharT, _Traits>& __is,
1197	       poisson_distribution<_IntType, _RealType>& __x)
1198    {
1199      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1200      typedef typename __istream_type::ios_base    __ios_base;
1201
1202      const typename __ios_base::fmtflags __flags = __is.flags();
1203      __is.flags(__ios_base::skipws);
1204
1205      __is >> __x._M_mean >> __x._M_nd;
1206      __x._M_initialize();
1207
1208      __is.flags(__flags);
1209      return __is;
1210    }
1211
1212
1213  template<typename _IntType, typename _RealType>
1214    void
1215    binomial_distribution<_IntType, _RealType>::
1216    _M_initialize()
1217    {
1218      const _RealType __p12 = _M_p <= 0.5 ? _M_p : 1.0 - _M_p;
1219
1220      _M_easy = true;
1221
1222#if _GLIBCXX_USE_C99_MATH_TR1
1223      if (_M_t * __p12 >= 8)
1224	{
1225	  _M_easy = false;
1226	  const _RealType __np = std::floor(_M_t * __p12);
1227	  const _RealType __pa = __np / _M_t;
1228	  const _RealType __1p = 1 - __pa;
1229	  
1230	  const _RealType __pi_4 = 0.7853981633974483096156608458198757L;
1231	  const _RealType __d1x =
1232	    std::sqrt(__np * __1p * std::log(32 * __np
1233					     / (81 * __pi_4 * __1p)));
1234	  _M_d1 = std::tr1::round(std::max(_RealType(1), __d1x));
1235	  const _RealType __d2x =
1236	    std::sqrt(__np * __1p * std::log(32 * _M_t * __1p
1237					     / (__pi_4 * __pa)));
1238	  _M_d2 = std::tr1::round(std::max(_RealType(1), __d2x));
1239	  
1240	  // sqrt(pi / 2)
1241	  const _RealType __spi_2 = 1.2533141373155002512078826424055226L;
1242	  _M_s1 = std::sqrt(__np * __1p) * (1 + _M_d1 / (4 * __np));
1243	  _M_s2 = std::sqrt(__np * __1p) * (1 + _M_d2 / (4 * _M_t * __1p));
1244	  _M_c = 2 * _M_d1 / __np;
1245	  _M_a1 = std::exp(_M_c) * _M_s1 * __spi_2;
1246	  const _RealType __a12 = _M_a1 + _M_s2 * __spi_2;
1247	  const _RealType __s1s = _M_s1 * _M_s1;
1248	  _M_a123 = __a12 + (std::exp(_M_d1 / (_M_t * __1p))
1249			     * 2 * __s1s / _M_d1
1250			     * std::exp(-_M_d1 * _M_d1 / (2 * __s1s)));
1251	  const _RealType __s2s = _M_s2 * _M_s2;
1252	  _M_s = (_M_a123 + 2 * __s2s / _M_d2
1253		  * std::exp(-_M_d2 * _M_d2 / (2 * __s2s)));
1254	  _M_lf = (std::tr1::lgamma(__np + 1)
1255		   + std::tr1::lgamma(_M_t - __np + 1));
1256	  _M_lp1p = std::log(__pa / __1p);
1257
1258	  _M_q = -std::log(1 - (__p12 - __pa) / __1p);
1259	}
1260      else
1261#endif
1262	_M_q = -std::log(1 - __p12);
1263    }
1264
1265  template<typename _IntType, typename _RealType>
1266    template<class _UniformRandomNumberGenerator>
1267      typename binomial_distribution<_IntType, _RealType>::result_type
1268      binomial_distribution<_IntType, _RealType>::
1269      _M_waiting(_UniformRandomNumberGenerator& __urng, _IntType __t)
1270      {
1271	_IntType    __x = 0;
1272	_RealType __sum = 0;
1273
1274	do
1275	  {
1276	    const _RealType __e = -std::log(__urng());
1277	    __sum += __e / (__t - __x);
1278	    __x += 1;
1279	  }
1280	while (__sum <= _M_q);
1281
1282	return __x - 1;
1283      }
1284
1285  /**
1286   * A rejection algorithm when t * p >= 8 and a simple waiting time
1287   * method - the second in the referenced book - otherwise.
1288   * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
1289   * is defined.
1290   *
1291   * Reference:
1292   * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1293   * New York, 1986, Ch. X, Sect. 4 (+ Errata!).
1294   */
1295  template<typename _IntType, typename _RealType>
1296    template<class _UniformRandomNumberGenerator>
1297      typename binomial_distribution<_IntType, _RealType>::result_type
1298      binomial_distribution<_IntType, _RealType>::
1299      operator()(_UniformRandomNumberGenerator& __urng)
1300      {
1301	result_type __ret;
1302	const _RealType __p12 = _M_p <= 0.5 ? _M_p : 1.0 - _M_p;
1303
1304#if _GLIBCXX_USE_C99_MATH_TR1
1305	if (!_M_easy)
1306	  {
1307	    _RealType __x;
1308
1309	    // See comments above...
1310	    const _RealType __naf =
1311	      (1 - std::numeric_limits<_RealType>::epsilon()) / 2;
1312	    const _RealType __thr =
1313	      std::numeric_limits<_IntType>::max() + __naf;
1314
1315	    const _RealType __np = std::floor(_M_t * __p12);
1316	    const _RealType __pa = __np / _M_t;
1317
1318	    // sqrt(pi / 2)
1319	    const _RealType __spi_2 = 1.2533141373155002512078826424055226L;
1320	    const _RealType __a1 = _M_a1;
1321	    const _RealType __a12 = __a1 + _M_s2 * __spi_2;
1322	    const _RealType __a123 = _M_a123;
1323	    const _RealType __s1s = _M_s1 * _M_s1;
1324	    const _RealType __s2s = _M_s2 * _M_s2;
1325
1326	    bool __reject;
1327	    do
1328	      {
1329		const _RealType __u = _M_s * __urng();
1330
1331		_RealType __v;
1332
1333		if (__u <= __a1)
1334		  {
1335		    const _RealType __n = _M_nd(__urng);
1336		    const _RealType __y = _M_s1 * std::abs(__n);
1337		    __reject = __y >= _M_d1;
1338		    if (!__reject)
1339		      {
1340			const _RealType __e = -std::log(__urng());
1341			__x = std::floor(__y);
1342			__v = -__e - __n * __n / 2 + _M_c;
1343		      }
1344		  }
1345		else if (__u <= __a12)
1346		  {
1347		    const _RealType __n = _M_nd(__urng);
1348		    const _RealType __y = _M_s2 * std::abs(__n);
1349		    __reject = __y >= _M_d2;
1350		    if (!__reject)
1351		      {
1352			const _RealType __e = -std::log(__urng());
1353			__x = std::floor(-__y);
1354			__v = -__e - __n * __n / 2;
1355		      }
1356		  }
1357		else if (__u <= __a123)
1358		  {
1359		    const _RealType __e1 = -std::log(__urng());		    
1360		    const _RealType __e2 = -std::log(__urng());
1361
1362		    const _RealType __y = _M_d1 + 2 * __s1s * __e1 / _M_d1;
1363		    __x = std::floor(__y);
1364		    __v = (-__e2 + _M_d1 * (1 / (_M_t - __np)
1365					    -__y / (2 * __s1s)));
1366		    __reject = false;
1367		  }
1368		else
1369		  {
1370		    const _RealType __e1 = -std::log(__urng());		    
1371		    const _RealType __e2 = -std::log(__urng());
1372
1373		    const _RealType __y = _M_d2 + 2 * __s2s * __e1 / _M_d2;
1374		    __x = std::floor(-__y);
1375		    __v = -__e2 - _M_d2 * __y / (2 * __s2s);
1376		    __reject = false;
1377		  }
1378
1379		__reject = __reject || __x < -__np || __x > _M_t - __np;
1380		if (!__reject)
1381		  {
1382		    const _RealType __lfx =
1383		      std::tr1::lgamma(__np + __x + 1)
1384		      + std::tr1::lgamma(_M_t - (__np + __x) + 1);
1385		    __reject = __v > _M_lf - __lfx + __x * _M_lp1p;
1386		  }
1387
1388		__reject |= __x + __np >= __thr;
1389	      }
1390	    while (__reject);
1391
1392	    __x += __np + __naf;
1393
1394	    const _IntType __z = _M_waiting(__urng, _M_t - _IntType(__x)); 
1395	    __ret = _IntType(__x) + __z;
1396	  }
1397	else
1398#endif
1399	  __ret = _M_waiting(__urng, _M_t);
1400
1401	if (__p12 != _M_p)
1402	  __ret = _M_t - __ret;
1403	return __ret;
1404      }
1405
1406  template<typename _IntType, typename _RealType,
1407	   typename _CharT, typename _Traits>
1408    std::basic_ostream<_CharT, _Traits>&
1409    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1410	       const binomial_distribution<_IntType, _RealType>& __x)
1411    {
1412      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1413      typedef typename __ostream_type::ios_base    __ios_base;
1414
1415      const typename __ios_base::fmtflags __flags = __os.flags();
1416      const _CharT __fill = __os.fill();
1417      const std::streamsize __precision = __os.precision();
1418      const _CharT __space = __os.widen(' ');
1419      __os.flags(__ios_base::scientific | __ios_base::left);
1420      __os.fill(__space);
1421      __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1422
1423      __os << __x.t() << __space << __x.p() 
1424	   << __space << __x._M_nd;
1425
1426      __os.flags(__flags);
1427      __os.fill(__fill);
1428      __os.precision(__precision);
1429      return __os;
1430    }
1431
1432  template<typename _IntType, typename _RealType,
1433	   typename _CharT, typename _Traits>
1434    std::basic_istream<_CharT, _Traits>&
1435    operator>>(std::basic_istream<_CharT, _Traits>& __is,
1436	       binomial_distribution<_IntType, _RealType>& __x)
1437    {
1438      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1439      typedef typename __istream_type::ios_base    __ios_base;
1440
1441      const typename __ios_base::fmtflags __flags = __is.flags();
1442      __is.flags(__ios_base::dec | __ios_base::skipws);
1443
1444      __is >> __x._M_t >> __x._M_p >> __x._M_nd;
1445      __x._M_initialize();
1446
1447      __is.flags(__flags);
1448      return __is;
1449    }
1450
1451
1452  template<typename _RealType, typename _CharT, typename _Traits>
1453    std::basic_ostream<_CharT, _Traits>&
1454    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1455	       const uniform_real<_RealType>& __x)
1456    {
1457      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1458      typedef typename __ostream_type::ios_base    __ios_base;
1459
1460      const typename __ios_base::fmtflags __flags = __os.flags();
1461      const _CharT __fill = __os.fill();
1462      const std::streamsize __precision = __os.precision();
1463      const _CharT __space = __os.widen(' ');
1464      __os.flags(__ios_base::scientific | __ios_base::left);
1465      __os.fill(__space);
1466      __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1467
1468      __os << __x.min() << __space << __x.max();
1469
1470      __os.flags(__flags);
1471      __os.fill(__fill);
1472      __os.precision(__precision);
1473      return __os;
1474    }
1475
1476  template<typename _RealType, typename _CharT, typename _Traits>
1477    std::basic_istream<_CharT, _Traits>&
1478    operator>>(std::basic_istream<_CharT, _Traits>& __is,
1479	       uniform_real<_RealType>& __x)
1480    {
1481      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1482      typedef typename __istream_type::ios_base    __ios_base;
1483
1484      const typename __ios_base::fmtflags __flags = __is.flags();
1485      __is.flags(__ios_base::skipws);
1486
1487      __is >> __x._M_min >> __x._M_max;
1488
1489      __is.flags(__flags);
1490      return __is;
1491    }
1492
1493
1494  template<typename _RealType, typename _CharT, typename _Traits>
1495    std::basic_ostream<_CharT, _Traits>&
1496    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1497	       const exponential_distribution<_RealType>& __x)
1498    {
1499      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1500      typedef typename __ostream_type::ios_base    __ios_base;
1501
1502      const typename __ios_base::fmtflags __flags = __os.flags();
1503      const _CharT __fill = __os.fill();
1504      const std::streamsize __precision = __os.precision();
1505      __os.flags(__ios_base::scientific | __ios_base::left);
1506      __os.fill(__os.widen(' '));
1507      __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1508
1509      __os << __x.lambda();
1510
1511      __os.flags(__flags);
1512      __os.fill(__fill);
1513      __os.precision(__precision);
1514      return __os;
1515    }
1516
1517
1518  /**
1519   * Polar method due to Marsaglia.
1520   *
1521   * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1522   * New York, 1986, Ch. V, Sect. 4.4.
1523   */
1524  template<typename _RealType>
1525    template<class _UniformRandomNumberGenerator>
1526      typename normal_distribution<_RealType>::result_type
1527      normal_distribution<_RealType>::
1528      operator()(_UniformRandomNumberGenerator& __urng)
1529      {
1530	result_type __ret;
1531
1532	if (_M_saved_available)
1533	  {
1534	    _M_saved_available = false;
1535	    __ret = _M_saved;
1536	  }
1537	else
1538	  {
1539	    result_type __x, __y, __r2;
1540	    do
1541	      {
1542		__x = result_type(2.0) * __urng() - 1.0;
1543		__y = result_type(2.0) * __urng() - 1.0;
1544		__r2 = __x * __x + __y * __y;
1545	      }
1546	    while (__r2 > 1.0 || __r2 == 0.0);
1547
1548	    const result_type __mult = std::sqrt(-2 * std::log(__r2) / __r2);
1549	    _M_saved = __x * __mult;
1550	    _M_saved_available = true;
1551	    __ret = __y * __mult;
1552	  }
1553	
1554	__ret = __ret * _M_sigma + _M_mean;
1555	return __ret;
1556      }
1557
1558  template<typename _RealType, typename _CharT, typename _Traits>
1559    std::basic_ostream<_CharT, _Traits>&
1560    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1561	       const normal_distribution<_RealType>& __x)
1562    {
1563      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1564      typedef typename __ostream_type::ios_base    __ios_base;
1565
1566      const typename __ios_base::fmtflags __flags = __os.flags();
1567      const _CharT __fill = __os.fill();
1568      const std::streamsize __precision = __os.precision();
1569      const _CharT __space = __os.widen(' ');
1570      __os.flags(__ios_base::scientific | __ios_base::left);
1571      __os.fill(__space);
1572      __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1573
1574      __os << __x._M_saved_available << __space
1575	   << __x.mean() << __space
1576	   << __x.sigma();
1577      if (__x._M_saved_available)
1578	__os << __space << __x._M_saved;
1579
1580      __os.flags(__flags);
1581      __os.fill(__fill);
1582      __os.precision(__precision);
1583      return __os;
1584    }
1585
1586  template<typename _RealType, typename _CharT, typename _Traits>
1587    std::basic_istream<_CharT, _Traits>&
1588    operator>>(std::basic_istream<_CharT, _Traits>& __is,
1589	       normal_distribution<_RealType>& __x)
1590    {
1591      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1592      typedef typename __istream_type::ios_base    __ios_base;
1593
1594      const typename __ios_base::fmtflags __flags = __is.flags();
1595      __is.flags(__ios_base::dec | __ios_base::skipws);
1596
1597      __is >> __x._M_saved_available >> __x._M_mean
1598	   >> __x._M_sigma;
1599      if (__x._M_saved_available)
1600	__is >> __x._M_saved;
1601
1602      __is.flags(__flags);
1603      return __is;
1604    }
1605
1606
1607  template<typename _RealType>
1608    void
1609    gamma_distribution<_RealType>::
1610    _M_initialize()
1611    {
1612      if (_M_alpha >= 1)
1613	_M_l_d = std::sqrt(2 * _M_alpha - 1);
1614      else
1615	_M_l_d = (std::pow(_M_alpha, _M_alpha / (1 - _M_alpha))
1616		  * (1 - _M_alpha));
1617    }
1618
1619  /**
1620   * Cheng's rejection algorithm GB for alpha >= 1 and a modification
1621   * of Vaduva's rejection from Weibull algorithm due to Devroye for
1622   * alpha < 1.
1623   *
1624   * References:
1625   * Cheng, R. C. The Generation of Gamma Random Variables with Non-integral
1626   * Shape Parameter. Applied Statistics, 26, 71-75, 1977.
1627   *
1628   * Vaduva, I. Computer Generation of Gamma Gandom Variables by Rejection
1629   * and Composition Procedures. Math. Operationsforschung and Statistik,
1630   * Series in Statistics, 8, 545-576, 1977.
1631   *
1632   * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1633   * New York, 1986, Ch. IX, Sect. 3.4 (+ Errata!).
1634   */
1635  template<typename _RealType>
1636    template<class _UniformRandomNumberGenerator>
1637      typename gamma_distribution<_RealType>::result_type
1638      gamma_distribution<_RealType>::
1639      operator()(_UniformRandomNumberGenerator& __urng)
1640      {
1641	result_type __x;
1642
1643	bool __reject;
1644	if (_M_alpha >= 1)
1645	  {
1646	    // alpha - log(4)
1647	    const result_type __b = _M_alpha
1648	      - result_type(1.3862943611198906188344642429163531L);
1649	    const result_type __c = _M_alpha + _M_l_d;
1650	    const result_type __1l = 1 / _M_l_d;
1651
1652	    // 1 + log(9 / 2)
1653	    const result_type __k = 2.5040773967762740733732583523868748L;
1654
1655	    do
1656	      {
1657		const result_type __u = __urng();
1658		const result_type __v = __urng();
1659
1660		const result_type __y = __1l * std::log(__v / (1 - __v));
1661		__x = _M_alpha * std::exp(__y);
1662
1663		const result_type __z = __u * __v * __v;
1664		const result_type __r = __b + __c * __y - __x;
1665
1666		__reject = __r < result_type(4.5) * __z - __k;
1667		if (__reject)
1668		  __reject = __r < std::log(__z);
1669	      }
1670	    while (__reject);
1671	  }
1672	else
1673	  {
1674	    const result_type __c = 1 / _M_alpha;
1675
1676	    do
1677	      {
1678		const result_type __z = -std::log(__urng());
1679		const result_type __e = -std::log(__urng());
1680
1681		__x = std::pow(__z, __c);
1682
1683		__reject = __z + __e < _M_l_d + __x;
1684	      }
1685	    while (__reject);
1686	  }
1687
1688	return __x;
1689      }
1690
1691  template<typename _RealType, typename _CharT, typename _Traits>
1692    std::basic_ostream<_CharT, _Traits>&
1693    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1694	       const gamma_distribution<_RealType>& __x)
1695    {
1696      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1697      typedef typename __ostream_type::ios_base    __ios_base;
1698
1699      const typename __ios_base::fmtflags __flags = __os.flags();
1700      const _CharT __fill = __os.fill();
1701      const std::streamsize __precision = __os.precision();
1702      __os.flags(__ios_base::scientific | __ios_base::left);
1703      __os.fill(__os.widen(' '));
1704      __os.precision(__gnu_cxx::__numeric_traits<_RealType>::__max_digits10);
1705
1706      __os << __x.alpha();
1707
1708      __os.flags(__flags);
1709      __os.fill(__fill);
1710      __os.precision(__precision);
1711      return __os;
1712    }
1713}
1714
1715_GLIBCXX_END_NAMESPACE_VERSION
1716}
1717
1718#endif
1719