1 // random number generation (out of line) -*- C++ -*-
2 
3 // Copyright (C) 2009-2012 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 /** @file bits/random.tcc
26  *  This is an internal header file, included by other library headers.
27  *  Do not attempt to use it directly. @headername{random}
28  */
29 
30 #ifndef _RANDOM_TCC
31 #define _RANDOM_TCC 1
32 
33 #include <numeric> // std::accumulate and std::partial_sum
34 
35 namespace std _GLIBCXX_VISIBILITY(default)
36 {
37   /*
38    * (Further) implementation-space details.
39    */
40   namespace __detail
41   {
42   _GLIBCXX_BEGIN_NAMESPACE_VERSION
43 
44     // General case for x = (ax + c) mod m -- use Schrage's algorithm to
45     // avoid integer overflow.
46     //
47     // Because a and c are compile-time integral constants the compiler
48     // kindly elides any unreachable paths.
49     //
50     // Preconditions:  a > 0, m > 0.
51     //
52     // XXX FIXME: as-is, only works correctly for __m % __a < __m / __a.
53     //
54     template<typename _Tp, _Tp __m, _Tp __a, _Tp __c, bool>
55       struct _Mod
56       {
57 	static _Tp
58 	__calc(_Tp __x)
59 	{
60 	  if (__a == 1)
61 	    __x %= __m;
62 	  else
63 	    {
64 	      static const _Tp __q = __m / __a;
65 	      static const _Tp __r = __m % __a;
66 
67 	      _Tp __t1 = __a * (__x % __q);
68 	      _Tp __t2 = __r * (__x / __q);
69 	      if (__t1 >= __t2)
70 		__x = __t1 - __t2;
71 	      else
72 		__x = __m - __t2 + __t1;
73 	    }
74 
75 	  if (__c != 0)
76 	    {
77 	      const _Tp __d = __m - __x;
78 	      if (__d > __c)
79 		__x += __c;
80 	      else
81 		__x = __c - __d;
82 	    }
83 	  return __x;
84 	}
85       };
86 
87     // Special case for m == 0 -- use unsigned integer overflow as modulo
88     // operator.
89     template<typename _Tp, _Tp __m, _Tp __a, _Tp __c>
90       struct _Mod<_Tp, __m, __a, __c, true>
91       {
92 	static _Tp
93 	__calc(_Tp __x)
94 	{ return __a * __x + __c; }
95       };
96 
97     template<typename _InputIterator, typename _OutputIterator,
98 	     typename _UnaryOperation>
99       _OutputIterator
100       __transform(_InputIterator __first, _InputIterator __last,
101 		  _OutputIterator __result, _UnaryOperation __unary_op)
102       {
103 	for (; __first != __last; ++__first, ++__result)
104 	  *__result = __unary_op(*__first);
105 	return __result;
106       }
107 
108   _GLIBCXX_END_NAMESPACE_VERSION
109   } // namespace __detail
110 
111 _GLIBCXX_BEGIN_NAMESPACE_VERSION
112 
113   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
114     constexpr _UIntType
115     linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
116 
117   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
118     constexpr _UIntType
119     linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
120 
121   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
122     constexpr _UIntType
123     linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
124 
125   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
126     constexpr _UIntType
127     linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
128 
129   /**
130    * Seeds the LCR with integral value @p __s, adjusted so that the
131    * ring identity is never a member of the convergence set.
132    */
133   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
134     void
135     linear_congruential_engine<_UIntType, __a, __c, __m>::
136     seed(result_type __s)
137     {
138       if ((__detail::__mod<_UIntType, __m>(__c) == 0)
139 	  && (__detail::__mod<_UIntType, __m>(__s) == 0))
140 	_M_x = 1;
141       else
142 	_M_x = __detail::__mod<_UIntType, __m>(__s);
143     }
144 
145   /**
146    * Seeds the LCR engine with a value generated by @p __q.
147    */
148   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
149     template<typename _Sseq>
150       typename std::enable_if<std::is_class<_Sseq>::value>::type
151       linear_congruential_engine<_UIntType, __a, __c, __m>::
152       seed(_Sseq& __q)
153       {
154 	const _UIntType __k0 = __m == 0 ? std::numeric_limits<_UIntType>::digits
155 	                                : std::__lg(__m);
156 	const _UIntType __k = (__k0 + 31) / 32;
157 	uint_least32_t __arr[__k + 3];
158 	__q.generate(__arr + 0, __arr + __k + 3);
159 	_UIntType __factor = 1u;
160 	_UIntType __sum = 0u;
161 	for (size_t __j = 0; __j < __k; ++__j)
162 	  {
163 	    __sum += __arr[__j + 3] * __factor;
164 	    __factor *= __detail::_Shift<_UIntType, 32>::__value;
165 	  }
166 	seed(__sum);
167       }
168 
169   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
170 	   typename _CharT, typename _Traits>
171     std::basic_ostream<_CharT, _Traits>&
172     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
173 	       const linear_congruential_engine<_UIntType,
174 						__a, __c, __m>& __lcr)
175     {
176       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
177       typedef typename __ostream_type::ios_base    __ios_base;
178 
179       const typename __ios_base::fmtflags __flags = __os.flags();
180       const _CharT __fill = __os.fill();
181       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
182       __os.fill(__os.widen(' '));
183 
184       __os << __lcr._M_x;
185 
186       __os.flags(__flags);
187       __os.fill(__fill);
188       return __os;
189     }
190 
191   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
192 	   typename _CharT, typename _Traits>
193     std::basic_istream<_CharT, _Traits>&
194     operator>>(std::basic_istream<_CharT, _Traits>& __is,
195 	       linear_congruential_engine<_UIntType, __a, __c, __m>& __lcr)
196     {
197       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
198       typedef typename __istream_type::ios_base    __ios_base;
199 
200       const typename __ios_base::fmtflags __flags = __is.flags();
201       __is.flags(__ios_base::dec);
202 
203       __is >> __lcr._M_x;
204 
205       __is.flags(__flags);
206       return __is;
207     }
208 
209 
210   template<typename _UIntType,
211 	   size_t __w, size_t __n, size_t __m, size_t __r,
212 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
213 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
214 	   _UIntType __f>
215     constexpr size_t
216     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
217 			    __s, __b, __t, __c, __l, __f>::word_size;
218 
219   template<typename _UIntType,
220 	   size_t __w, size_t __n, size_t __m, size_t __r,
221 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
222 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
223 	   _UIntType __f>
224     constexpr size_t
225     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
226 			    __s, __b, __t, __c, __l, __f>::state_size;
227 
228   template<typename _UIntType,
229 	   size_t __w, size_t __n, size_t __m, size_t __r,
230 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
231 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
232 	   _UIntType __f>
233     constexpr size_t
234     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
235 			    __s, __b, __t, __c, __l, __f>::shift_size;
236 
237   template<typename _UIntType,
238 	   size_t __w, size_t __n, size_t __m, size_t __r,
239 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
240 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
241 	   _UIntType __f>
242     constexpr size_t
243     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
244 			    __s, __b, __t, __c, __l, __f>::mask_bits;
245 
246   template<typename _UIntType,
247 	   size_t __w, size_t __n, size_t __m, size_t __r,
248 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
249 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
250 	   _UIntType __f>
251     constexpr _UIntType
252     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
253 			    __s, __b, __t, __c, __l, __f>::xor_mask;
254 
255   template<typename _UIntType,
256 	   size_t __w, size_t __n, size_t __m, size_t __r,
257 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
258 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
259 	   _UIntType __f>
260     constexpr size_t
261     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
262 			    __s, __b, __t, __c, __l, __f>::tempering_u;
263 
264   template<typename _UIntType,
265 	   size_t __w, size_t __n, size_t __m, size_t __r,
266 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
267 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
268 	   _UIntType __f>
269     constexpr _UIntType
270     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
271 			    __s, __b, __t, __c, __l, __f>::tempering_d;
272 
273   template<typename _UIntType,
274 	   size_t __w, size_t __n, size_t __m, size_t __r,
275 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
276 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
277 	   _UIntType __f>
278     constexpr size_t
279     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
280 			    __s, __b, __t, __c, __l, __f>::tempering_s;
281 
282   template<typename _UIntType,
283 	   size_t __w, size_t __n, size_t __m, size_t __r,
284 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
285 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
286 	   _UIntType __f>
287     constexpr _UIntType
288     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
289 			    __s, __b, __t, __c, __l, __f>::tempering_b;
290 
291   template<typename _UIntType,
292 	   size_t __w, size_t __n, size_t __m, size_t __r,
293 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
294 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
295 	   _UIntType __f>
296     constexpr size_t
297     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
298 			    __s, __b, __t, __c, __l, __f>::tempering_t;
299 
300   template<typename _UIntType,
301 	   size_t __w, size_t __n, size_t __m, size_t __r,
302 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
303 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
304 	   _UIntType __f>
305     constexpr _UIntType
306     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
307 			    __s, __b, __t, __c, __l, __f>::tempering_c;
308 
309   template<typename _UIntType,
310 	   size_t __w, size_t __n, size_t __m, size_t __r,
311 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
312 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
313 	   _UIntType __f>
314     constexpr size_t
315     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
316 			    __s, __b, __t, __c, __l, __f>::tempering_l;
317 
318   template<typename _UIntType,
319 	   size_t __w, size_t __n, size_t __m, size_t __r,
320 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
321 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
322 	   _UIntType __f>
323     constexpr _UIntType
324     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
325 			    __s, __b, __t, __c, __l, __f>::
326                                               initialization_multiplier;
327 
328   template<typename _UIntType,
329 	   size_t __w, size_t __n, size_t __m, size_t __r,
330 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
331 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
332 	   _UIntType __f>
333     constexpr _UIntType
334     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
335 			    __s, __b, __t, __c, __l, __f>::default_seed;
336 
337   template<typename _UIntType,
338 	   size_t __w, size_t __n, size_t __m, size_t __r,
339 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
340 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
341 	   _UIntType __f>
342     void
343     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
344 			    __s, __b, __t, __c, __l, __f>::
345     seed(result_type __sd)
346     {
347       _M_x[0] = __detail::__mod<_UIntType,
348 	__detail::_Shift<_UIntType, __w>::__value>(__sd);
349 
350       for (size_t __i = 1; __i < state_size; ++__i)
351 	{
352 	  _UIntType __x = _M_x[__i - 1];
353 	  __x ^= __x >> (__w - 2);
354 	  __x *= __f;
355 	  __x += __detail::__mod<_UIntType, __n>(__i);
356 	  _M_x[__i] = __detail::__mod<_UIntType,
357 	    __detail::_Shift<_UIntType, __w>::__value>(__x);
358 	}
359       _M_p = state_size;
360     }
361 
362   template<typename _UIntType,
363 	   size_t __w, size_t __n, size_t __m, size_t __r,
364 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
365 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
366 	   _UIntType __f>
367     template<typename _Sseq>
368       typename std::enable_if<std::is_class<_Sseq>::value>::type
369       mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
370 			      __s, __b, __t, __c, __l, __f>::
371       seed(_Sseq& __q)
372       {
373 	const _UIntType __upper_mask = (~_UIntType()) << __r;
374 	const size_t __k = (__w + 31) / 32;
375 	uint_least32_t __arr[__n * __k];
376 	__q.generate(__arr + 0, __arr + __n * __k);
377 
378 	bool __zero = true;
379 	for (size_t __i = 0; __i < state_size; ++__i)
380 	  {
381 	    _UIntType __factor = 1u;
382 	    _UIntType __sum = 0u;
383 	    for (size_t __j = 0; __j < __k; ++__j)
384 	      {
385 		__sum += __arr[__k * __i + __j] * __factor;
386 		__factor *= __detail::_Shift<_UIntType, 32>::__value;
387 	      }
388 	    _M_x[__i] = __detail::__mod<_UIntType,
389 	      __detail::_Shift<_UIntType, __w>::__value>(__sum);
390 
391 	    if (__zero)
392 	      {
393 		if (__i == 0)
394 		  {
395 		    if ((_M_x[0] & __upper_mask) != 0u)
396 		      __zero = false;
397 		  }
398 		else if (_M_x[__i] != 0u)
399 		  __zero = false;
400 	      }
401 	  }
402         if (__zero)
403           _M_x[0] = __detail::_Shift<_UIntType, __w - 1>::__value;
404 	_M_p = state_size;
405       }
406 
407   template<typename _UIntType, size_t __w,
408 	   size_t __n, size_t __m, size_t __r,
409 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
410 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
411 	   _UIntType __f>
412     typename
413     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
414 			    __s, __b, __t, __c, __l, __f>::result_type
415     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
416 			    __s, __b, __t, __c, __l, __f>::
417     operator()()
418     {
419       // Reload the vector - cost is O(n) amortized over n calls.
420       if (_M_p >= state_size)
421 	{
422 	  const _UIntType __upper_mask = (~_UIntType()) << __r;
423 	  const _UIntType __lower_mask = ~__upper_mask;
424 
425 	  for (size_t __k = 0; __k < (__n - __m); ++__k)
426 	    {
427 	      _UIntType __y = ((_M_x[__k] & __upper_mask)
428 			       | (_M_x[__k + 1] & __lower_mask));
429 	      _M_x[__k] = (_M_x[__k + __m] ^ (__y >> 1)
430 			   ^ ((__y & 0x01) ? __a : 0));
431 	    }
432 
433 	  for (size_t __k = (__n - __m); __k < (__n - 1); ++__k)
434 	    {
435 	      _UIntType __y = ((_M_x[__k] & __upper_mask)
436 			       | (_M_x[__k + 1] & __lower_mask));
437 	      _M_x[__k] = (_M_x[__k + (__m - __n)] ^ (__y >> 1)
438 			   ^ ((__y & 0x01) ? __a : 0));
439 	    }
440 
441 	  _UIntType __y = ((_M_x[__n - 1] & __upper_mask)
442 			   | (_M_x[0] & __lower_mask));
443 	  _M_x[__n - 1] = (_M_x[__m - 1] ^ (__y >> 1)
444 			   ^ ((__y & 0x01) ? __a : 0));
445 	  _M_p = 0;
446 	}
447 
448       // Calculate o(x(i)).
449       result_type __z = _M_x[_M_p++];
450       __z ^= (__z >> __u) & __d;
451       __z ^= (__z << __s) & __b;
452       __z ^= (__z << __t) & __c;
453       __z ^= (__z >> __l);
454 
455       return __z;
456     }
457 
458   template<typename _UIntType, size_t __w,
459 	   size_t __n, size_t __m, size_t __r,
460 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
461 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
462 	   _UIntType __f, typename _CharT, typename _Traits>
463     std::basic_ostream<_CharT, _Traits>&
464     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
465 	       const mersenne_twister_engine<_UIntType, __w, __n, __m,
466 	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __x)
467     {
468       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
469       typedef typename __ostream_type::ios_base    __ios_base;
470 
471       const typename __ios_base::fmtflags __flags = __os.flags();
472       const _CharT __fill = __os.fill();
473       const _CharT __space = __os.widen(' ');
474       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
475       __os.fill(__space);
476 
477       for (size_t __i = 0; __i < __n; ++__i)
478 	__os << __x._M_x[__i] << __space;
479       __os << __x._M_p;
480 
481       __os.flags(__flags);
482       __os.fill(__fill);
483       return __os;
484     }
485 
486   template<typename _UIntType, size_t __w,
487 	   size_t __n, size_t __m, size_t __r,
488 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
489 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
490 	   _UIntType __f, typename _CharT, typename _Traits>
491     std::basic_istream<_CharT, _Traits>&
492     operator>>(std::basic_istream<_CharT, _Traits>& __is,
493 	       mersenne_twister_engine<_UIntType, __w, __n, __m,
494 	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __x)
495     {
496       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
497       typedef typename __istream_type::ios_base    __ios_base;
498 
499       const typename __ios_base::fmtflags __flags = __is.flags();
500       __is.flags(__ios_base::dec | __ios_base::skipws);
501 
502       for (size_t __i = 0; __i < __n; ++__i)
503 	__is >> __x._M_x[__i];
504       __is >> __x._M_p;
505 
506       __is.flags(__flags);
507       return __is;
508     }
509 
510 
511   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
512     constexpr size_t
513     subtract_with_carry_engine<_UIntType, __w, __s, __r>::word_size;
514 
515   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
516     constexpr size_t
517     subtract_with_carry_engine<_UIntType, __w, __s, __r>::short_lag;
518 
519   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
520     constexpr size_t
521     subtract_with_carry_engine<_UIntType, __w, __s, __r>::long_lag;
522 
523   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
524     constexpr _UIntType
525     subtract_with_carry_engine<_UIntType, __w, __s, __r>::default_seed;
526 
527   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
528     void
529     subtract_with_carry_engine<_UIntType, __w, __s, __r>::
530     seed(result_type __value)
531     {
532       std::linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
533 	__lcg(__value == 0u ? default_seed : __value);
534 
535       const size_t __n = (__w + 31) / 32;
536 
537       for (size_t __i = 0; __i < long_lag; ++__i)
538 	{
539 	  _UIntType __sum = 0u;
540 	  _UIntType __factor = 1u;
541 	  for (size_t __j = 0; __j < __n; ++__j)
542 	    {
543 	      __sum += __detail::__mod<uint_least32_t,
544 		       __detail::_Shift<uint_least32_t, 32>::__value>
545 			 (__lcg()) * __factor;
546 	      __factor *= __detail::_Shift<_UIntType, 32>::__value;
547 	    }
548 	  _M_x[__i] = __detail::__mod<_UIntType,
549 	    __detail::_Shift<_UIntType, __w>::__value>(__sum);
550 	}
551       _M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
552       _M_p = 0;
553     }
554 
555   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
556     template<typename _Sseq>
557       typename std::enable_if<std::is_class<_Sseq>::value>::type
558       subtract_with_carry_engine<_UIntType, __w, __s, __r>::
559       seed(_Sseq& __q)
560       {
561 	const size_t __k = (__w + 31) / 32;
562 	uint_least32_t __arr[__r * __k];
563 	__q.generate(__arr + 0, __arr + __r * __k);
564 
565 	for (size_t __i = 0; __i < long_lag; ++__i)
566 	  {
567 	    _UIntType __sum = 0u;
568 	    _UIntType __factor = 1u;
569 	    for (size_t __j = 0; __j < __k; ++__j)
570 	      {
571 		__sum += __arr[__k * __i + __j] * __factor;
572 		__factor *= __detail::_Shift<_UIntType, 32>::__value;
573 	      }
574 	    _M_x[__i] = __detail::__mod<_UIntType,
575 	      __detail::_Shift<_UIntType, __w>::__value>(__sum);
576 	  }
577 	_M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
578 	_M_p = 0;
579       }
580 
581   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
582     typename subtract_with_carry_engine<_UIntType, __w, __s, __r>::
583 	     result_type
584     subtract_with_carry_engine<_UIntType, __w, __s, __r>::
585     operator()()
586     {
587       // Derive short lag index from current index.
588       long __ps = _M_p - short_lag;
589       if (__ps < 0)
590 	__ps += long_lag;
591 
592       // Calculate new x(i) without overflow or division.
593       // NB: Thanks to the requirements for _UIntType, _M_x[_M_p] + _M_carry
594       // cannot overflow.
595       _UIntType __xi;
596       if (_M_x[__ps] >= _M_x[_M_p] + _M_carry)
597 	{
598 	  __xi = _M_x[__ps] - _M_x[_M_p] - _M_carry;
599 	  _M_carry = 0;
600 	}
601       else
602 	{
603 	  __xi = (__detail::_Shift<_UIntType, __w>::__value
604 		  - _M_x[_M_p] - _M_carry + _M_x[__ps]);
605 	  _M_carry = 1;
606 	}
607       _M_x[_M_p] = __xi;
608 
609       // Adjust current index to loop around in ring buffer.
610       if (++_M_p >= long_lag)
611 	_M_p = 0;
612 
613       return __xi;
614     }
615 
616   template<typename _UIntType, size_t __w, size_t __s, size_t __r,
617 	   typename _CharT, typename _Traits>
618     std::basic_ostream<_CharT, _Traits>&
619     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
620 	       const subtract_with_carry_engine<_UIntType,
621 						__w, __s, __r>& __x)
622     {
623       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
624       typedef typename __ostream_type::ios_base    __ios_base;
625 
626       const typename __ios_base::fmtflags __flags = __os.flags();
627       const _CharT __fill = __os.fill();
628       const _CharT __space = __os.widen(' ');
629       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
630       __os.fill(__space);
631 
632       for (size_t __i = 0; __i < __r; ++__i)
633 	__os << __x._M_x[__i] << __space;
634       __os << __x._M_carry << __space << __x._M_p;
635 
636       __os.flags(__flags);
637       __os.fill(__fill);
638       return __os;
639     }
640 
641   template<typename _UIntType, size_t __w, size_t __s, size_t __r,
642 	   typename _CharT, typename _Traits>
643     std::basic_istream<_CharT, _Traits>&
644     operator>>(std::basic_istream<_CharT, _Traits>& __is,
645 	       subtract_with_carry_engine<_UIntType, __w, __s, __r>& __x)
646     {
647       typedef std::basic_ostream<_CharT, _Traits>  __istream_type;
648       typedef typename __istream_type::ios_base    __ios_base;
649 
650       const typename __ios_base::fmtflags __flags = __is.flags();
651       __is.flags(__ios_base::dec | __ios_base::skipws);
652 
653       for (size_t __i = 0; __i < __r; ++__i)
654 	__is >> __x._M_x[__i];
655       __is >> __x._M_carry;
656       __is >> __x._M_p;
657 
658       __is.flags(__flags);
659       return __is;
660     }
661 
662 
663   template<typename _RandomNumberEngine, size_t __p, size_t __r>
664     constexpr size_t
665     discard_block_engine<_RandomNumberEngine, __p, __r>::block_size;
666 
667   template<typename _RandomNumberEngine, size_t __p, size_t __r>
668     constexpr size_t
669     discard_block_engine<_RandomNumberEngine, __p, __r>::used_block;
670 
671   template<typename _RandomNumberEngine, size_t __p, size_t __r>
672     typename discard_block_engine<_RandomNumberEngine,
673 			   __p, __r>::result_type
674     discard_block_engine<_RandomNumberEngine, __p, __r>::
675     operator()()
676     {
677       if (_M_n >= used_block)
678 	{
679 	  _M_b.discard(block_size - _M_n);
680 	  _M_n = 0;
681 	}
682       ++_M_n;
683       return _M_b();
684     }
685 
686   template<typename _RandomNumberEngine, size_t __p, size_t __r,
687 	   typename _CharT, typename _Traits>
688     std::basic_ostream<_CharT, _Traits>&
689     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
690 	       const discard_block_engine<_RandomNumberEngine,
691 	       __p, __r>& __x)
692     {
693       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
694       typedef typename __ostream_type::ios_base    __ios_base;
695 
696       const typename __ios_base::fmtflags __flags = __os.flags();
697       const _CharT __fill = __os.fill();
698       const _CharT __space = __os.widen(' ');
699       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
700       __os.fill(__space);
701 
702       __os << __x.base() << __space << __x._M_n;
703 
704       __os.flags(__flags);
705       __os.fill(__fill);
706       return __os;
707     }
708 
709   template<typename _RandomNumberEngine, size_t __p, size_t __r,
710 	   typename _CharT, typename _Traits>
711     std::basic_istream<_CharT, _Traits>&
712     operator>>(std::basic_istream<_CharT, _Traits>& __is,
713 	       discard_block_engine<_RandomNumberEngine, __p, __r>& __x)
714     {
715       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
716       typedef typename __istream_type::ios_base    __ios_base;
717 
718       const typename __ios_base::fmtflags __flags = __is.flags();
719       __is.flags(__ios_base::dec | __ios_base::skipws);
720 
721       __is >> __x._M_b >> __x._M_n;
722 
723       __is.flags(__flags);
724       return __is;
725     }
726 
727 
728   template<typename _RandomNumberEngine, size_t __w, typename _UIntType>
729     typename independent_bits_engine<_RandomNumberEngine, __w, _UIntType>::
730       result_type
731     independent_bits_engine<_RandomNumberEngine, __w, _UIntType>::
732     operator()()
733     {
734       typedef typename _RandomNumberEngine::result_type _Eresult_type;
735       const _Eresult_type __r
736 	= (_M_b.max() - _M_b.min() < std::numeric_limits<_Eresult_type>::max()
737 	   ? _M_b.max() - _M_b.min() + 1 : 0);
738       const unsigned __edig = std::numeric_limits<_Eresult_type>::digits;
739       const unsigned __m = __r ? std::__lg(__r) : __edig;
740 
741       typedef typename std::common_type<_Eresult_type, result_type>::type
742 	__ctype;
743       const unsigned __cdig = std::numeric_limits<__ctype>::digits;
744 
745       unsigned __n, __n0;
746       __ctype __s0, __s1, __y0, __y1;
747 
748       for (size_t __i = 0; __i < 2; ++__i)
749 	{
750 	  __n = (__w + __m - 1) / __m + __i;
751 	  __n0 = __n - __w % __n;
752 	  const unsigned __w0 = __w / __n;  // __w0 <= __m
753 
754 	  __s0 = 0;
755 	  __s1 = 0;
756 	  if (__w0 < __cdig)
757 	    {
758 	      __s0 = __ctype(1) << __w0;
759 	      __s1 = __s0 << 1;
760 	    }
761 
762 	  __y0 = 0;
763 	  __y1 = 0;
764 	  if (__r)
765 	    {
766 	      __y0 = __s0 * (__r / __s0);
767 	      if (__s1)
768 		__y1 = __s1 * (__r / __s1);
769 
770 	      if (__r - __y0 <= __y0 / __n)
771 		break;
772 	    }
773 	  else
774 	    break;
775 	}
776 
777       result_type __sum = 0;
778       for (size_t __k = 0; __k < __n0; ++__k)
779 	{
780 	  __ctype __u;
781 	  do
782 	    __u = _M_b() - _M_b.min();
783 	  while (__y0 && __u >= __y0);
784 	  __sum = __s0 * __sum + (__s0 ? __u % __s0 : __u);
785 	}
786       for (size_t __k = __n0; __k < __n; ++__k)
787 	{
788 	  __ctype __u;
789 	  do
790 	    __u = _M_b() - _M_b.min();
791 	  while (__y1 && __u >= __y1);
792 	  __sum = __s1 * __sum + (__s1 ? __u % __s1 : __u);
793 	}
794       return __sum;
795     }
796 
797 
798   template<typename _RandomNumberEngine, size_t __k>
799     constexpr size_t
800     shuffle_order_engine<_RandomNumberEngine, __k>::table_size;
801 
802   template<typename _RandomNumberEngine, size_t __k>
803     typename shuffle_order_engine<_RandomNumberEngine, __k>::result_type
804     shuffle_order_engine<_RandomNumberEngine, __k>::
805     operator()()
806     {
807       size_t __j = __k * ((_M_y - _M_b.min())
808 			  / (_M_b.max() - _M_b.min() + 1.0L));
809       _M_y = _M_v[__j];
810       _M_v[__j] = _M_b();
811 
812       return _M_y;
813     }
814 
815   template<typename _RandomNumberEngine, size_t __k,
816 	   typename _CharT, typename _Traits>
817     std::basic_ostream<_CharT, _Traits>&
818     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
819 	       const shuffle_order_engine<_RandomNumberEngine, __k>& __x)
820     {
821       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
822       typedef typename __ostream_type::ios_base    __ios_base;
823 
824       const typename __ios_base::fmtflags __flags = __os.flags();
825       const _CharT __fill = __os.fill();
826       const _CharT __space = __os.widen(' ');
827       __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
828       __os.fill(__space);
829 
830       __os << __x.base();
831       for (size_t __i = 0; __i < __k; ++__i)
832 	__os << __space << __x._M_v[__i];
833       __os << __space << __x._M_y;
834 
835       __os.flags(__flags);
836       __os.fill(__fill);
837       return __os;
838     }
839 
840   template<typename _RandomNumberEngine, size_t __k,
841 	   typename _CharT, typename _Traits>
842     std::basic_istream<_CharT, _Traits>&
843     operator>>(std::basic_istream<_CharT, _Traits>& __is,
844 	       shuffle_order_engine<_RandomNumberEngine, __k>& __x)
845     {
846       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
847       typedef typename __istream_type::ios_base    __ios_base;
848 
849       const typename __ios_base::fmtflags __flags = __is.flags();
850       __is.flags(__ios_base::dec | __ios_base::skipws);
851 
852       __is >> __x._M_b;
853       for (size_t __i = 0; __i < __k; ++__i)
854 	__is >> __x._M_v[__i];
855       __is >> __x._M_y;
856 
857       __is.flags(__flags);
858       return __is;
859     }
860 
861 
862   template<typename _IntType>
863     template<typename _UniformRandomNumberGenerator>
864       typename uniform_int_distribution<_IntType>::result_type
865       uniform_int_distribution<_IntType>::
866       operator()(_UniformRandomNumberGenerator& __urng,
867 		 const param_type& __param)
868       {
869 	typedef typename _UniformRandomNumberGenerator::result_type
870 	  _Gresult_type;
871 	typedef typename std::make_unsigned<result_type>::type __utype;
872 	typedef typename std::common_type<_Gresult_type, __utype>::type
873 	  __uctype;
874 
875 	const __uctype __urngmin = __urng.min();
876 	const __uctype __urngmax = __urng.max();
877 	const __uctype __urngrange = __urngmax - __urngmin;
878 	const __uctype __urange
879 	  = __uctype(__param.b()) - __uctype(__param.a());
880 
881 	__uctype __ret;
882 
883 	if (__urngrange > __urange)
884 	  {
885 	    // downscaling
886 	    const __uctype __uerange = __urange + 1; // __urange can be zero
887 	    const __uctype __scaling = __urngrange / __uerange;
888 	    const __uctype __past = __uerange * __scaling;
889 	    do
890 	      __ret = __uctype(__urng()) - __urngmin;
891 	    while (__ret >= __past);
892 	    __ret /= __scaling;
893 	  }
894 	else if (__urngrange < __urange)
895 	  {
896 	    // upscaling
897 	    /*
898 	      Note that every value in [0, urange]
899 	      can be written uniquely as
900 
901 	      (urngrange + 1) * high + low
902 
903 	      where
904 
905 	      high in [0, urange / (urngrange + 1)]
906 
907 	      and
908 
909 	      low in [0, urngrange].
910 	    */
911 	    __uctype __tmp; // wraparound control
912 	    do
913 	      {
914 		const __uctype __uerngrange = __urngrange + 1;
915 		__tmp = (__uerngrange * operator()
916 			 (__urng, param_type(0, __urange / __uerngrange)));
917 		__ret = __tmp + (__uctype(__urng()) - __urngmin);
918 	      }
919 	    while (__ret > __urange || __ret < __tmp);
920 	  }
921 	else
922 	  __ret = __uctype(__urng()) - __urngmin;
923 
924 	return __ret + __param.a();
925       }
926 
927   template<typename _IntType, typename _CharT, typename _Traits>
928     std::basic_ostream<_CharT, _Traits>&
929     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
930 	       const uniform_int_distribution<_IntType>& __x)
931     {
932       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
933       typedef typename __ostream_type::ios_base    __ios_base;
934 
935       const typename __ios_base::fmtflags __flags = __os.flags();
936       const _CharT __fill = __os.fill();
937       const _CharT __space = __os.widen(' ');
938       __os.flags(__ios_base::scientific | __ios_base::left);
939       __os.fill(__space);
940 
941       __os << __x.a() << __space << __x.b();
942 
943       __os.flags(__flags);
944       __os.fill(__fill);
945       return __os;
946     }
947 
948   template<typename _IntType, typename _CharT, typename _Traits>
949     std::basic_istream<_CharT, _Traits>&
950     operator>>(std::basic_istream<_CharT, _Traits>& __is,
951 	       uniform_int_distribution<_IntType>& __x)
952     {
953       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
954       typedef typename __istream_type::ios_base    __ios_base;
955 
956       const typename __ios_base::fmtflags __flags = __is.flags();
957       __is.flags(__ios_base::dec | __ios_base::skipws);
958 
959       _IntType __a, __b;
960       __is >> __a >> __b;
961       __x.param(typename uniform_int_distribution<_IntType>::
962 		param_type(__a, __b));
963 
964       __is.flags(__flags);
965       return __is;
966     }
967 
968 
969   template<typename _RealType, typename _CharT, typename _Traits>
970     std::basic_ostream<_CharT, _Traits>&
971     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
972 	       const uniform_real_distribution<_RealType>& __x)
973     {
974       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
975       typedef typename __ostream_type::ios_base    __ios_base;
976 
977       const typename __ios_base::fmtflags __flags = __os.flags();
978       const _CharT __fill = __os.fill();
979       const std::streamsize __precision = __os.precision();
980       const _CharT __space = __os.widen(' ');
981       __os.flags(__ios_base::scientific | __ios_base::left);
982       __os.fill(__space);
983       __os.precision(std::numeric_limits<_RealType>::max_digits10);
984 
985       __os << __x.a() << __space << __x.b();
986 
987       __os.flags(__flags);
988       __os.fill(__fill);
989       __os.precision(__precision);
990       return __os;
991     }
992 
993   template<typename _RealType, typename _CharT, typename _Traits>
994     std::basic_istream<_CharT, _Traits>&
995     operator>>(std::basic_istream<_CharT, _Traits>& __is,
996 	       uniform_real_distribution<_RealType>& __x)
997     {
998       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
999       typedef typename __istream_type::ios_base    __ios_base;
1000 
1001       const typename __ios_base::fmtflags __flags = __is.flags();
1002       __is.flags(__ios_base::skipws);
1003 
1004       _RealType __a, __b;
1005       __is >> __a >> __b;
1006       __x.param(typename uniform_real_distribution<_RealType>::
1007 		param_type(__a, __b));
1008 
1009       __is.flags(__flags);
1010       return __is;
1011     }
1012 
1013 
1014   template<typename _CharT, typename _Traits>
1015     std::basic_ostream<_CharT, _Traits>&
1016     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1017 	       const bernoulli_distribution& __x)
1018     {
1019       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1020       typedef typename __ostream_type::ios_base    __ios_base;
1021 
1022       const typename __ios_base::fmtflags __flags = __os.flags();
1023       const _CharT __fill = __os.fill();
1024       const std::streamsize __precision = __os.precision();
1025       __os.flags(__ios_base::scientific | __ios_base::left);
1026       __os.fill(__os.widen(' '));
1027       __os.precision(std::numeric_limits<double>::max_digits10);
1028 
1029       __os << __x.p();
1030 
1031       __os.flags(__flags);
1032       __os.fill(__fill);
1033       __os.precision(__precision);
1034       return __os;
1035     }
1036 
1037 
1038   template<typename _IntType>
1039     template<typename _UniformRandomNumberGenerator>
1040       typename geometric_distribution<_IntType>::result_type
1041       geometric_distribution<_IntType>::
1042       operator()(_UniformRandomNumberGenerator& __urng,
1043 		 const param_type& __param)
1044       {
1045 	// About the epsilon thing see this thread:
1046 	// http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00971.html
1047 	const double __naf =
1048 	  (1 - std::numeric_limits<double>::epsilon()) / 2;
1049 	// The largest _RealType convertible to _IntType.
1050 	const double __thr =
1051 	  std::numeric_limits<_IntType>::max() + __naf;
1052 	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
1053 	  __aurng(__urng);
1054 
1055 	double __cand;
1056 	do
1057 	  __cand = std::floor(std::log(1.0 - __aurng()) / __param._M_log_1_p);
1058 	while (__cand >= __thr);
1059 
1060 	return result_type(__cand + __naf);
1061       }
1062 
1063   template<typename _IntType,
1064 	   typename _CharT, typename _Traits>
1065     std::basic_ostream<_CharT, _Traits>&
1066     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1067 	       const geometric_distribution<_IntType>& __x)
1068     {
1069       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1070       typedef typename __ostream_type::ios_base    __ios_base;
1071 
1072       const typename __ios_base::fmtflags __flags = __os.flags();
1073       const _CharT __fill = __os.fill();
1074       const std::streamsize __precision = __os.precision();
1075       __os.flags(__ios_base::scientific | __ios_base::left);
1076       __os.fill(__os.widen(' '));
1077       __os.precision(std::numeric_limits<double>::max_digits10);
1078 
1079       __os << __x.p();
1080 
1081       __os.flags(__flags);
1082       __os.fill(__fill);
1083       __os.precision(__precision);
1084       return __os;
1085     }
1086 
1087   template<typename _IntType,
1088 	   typename _CharT, typename _Traits>
1089     std::basic_istream<_CharT, _Traits>&
1090     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1091 	       geometric_distribution<_IntType>& __x)
1092     {
1093       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1094       typedef typename __istream_type::ios_base    __ios_base;
1095 
1096       const typename __ios_base::fmtflags __flags = __is.flags();
1097       __is.flags(__ios_base::skipws);
1098 
1099       double __p;
1100       __is >> __p;
1101       __x.param(typename geometric_distribution<_IntType>::param_type(__p));
1102 
1103       __is.flags(__flags);
1104       return __is;
1105     }
1106 
1107   // This is Leger's algorithm, also in Devroye, Ch. X, Example 1.5.
1108   template<typename _IntType>
1109     template<typename _UniformRandomNumberGenerator>
1110       typename negative_binomial_distribution<_IntType>::result_type
1111       negative_binomial_distribution<_IntType>::
1112       operator()(_UniformRandomNumberGenerator& __urng)
1113       {
1114 	const double __y = _M_gd(__urng);
1115 
1116 	// XXX Is the constructor too slow?
1117 	std::poisson_distribution<result_type> __poisson(__y);
1118 	return __poisson(__urng);
1119       }
1120 
1121   template<typename _IntType>
1122     template<typename _UniformRandomNumberGenerator>
1123       typename negative_binomial_distribution<_IntType>::result_type
1124       negative_binomial_distribution<_IntType>::
1125       operator()(_UniformRandomNumberGenerator& __urng,
1126 		 const param_type& __p)
1127       {
1128 	typedef typename std::gamma_distribution<result_type>::param_type
1129 	  param_type;
1130 
1131 	const double __y =
1132 	  _M_gd(__urng, param_type(__p.k(), (1.0 - __p.p()) / __p.p()));
1133 
1134 	std::poisson_distribution<result_type> __poisson(__y);
1135 	return __poisson(__urng);
1136       }
1137 
1138   template<typename _IntType, typename _CharT, typename _Traits>
1139     std::basic_ostream<_CharT, _Traits>&
1140     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1141 	       const negative_binomial_distribution<_IntType>& __x)
1142     {
1143       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1144       typedef typename __ostream_type::ios_base    __ios_base;
1145 
1146       const typename __ios_base::fmtflags __flags = __os.flags();
1147       const _CharT __fill = __os.fill();
1148       const std::streamsize __precision = __os.precision();
1149       const _CharT __space = __os.widen(' ');
1150       __os.flags(__ios_base::scientific | __ios_base::left);
1151       __os.fill(__os.widen(' '));
1152       __os.precision(std::numeric_limits<double>::max_digits10);
1153 
1154       __os << __x.k() << __space << __x.p()
1155 	   << __space << __x._M_gd;
1156 
1157       __os.flags(__flags);
1158       __os.fill(__fill);
1159       __os.precision(__precision);
1160       return __os;
1161     }
1162 
1163   template<typename _IntType, typename _CharT, typename _Traits>
1164     std::basic_istream<_CharT, _Traits>&
1165     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1166 	       negative_binomial_distribution<_IntType>& __x)
1167     {
1168       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1169       typedef typename __istream_type::ios_base    __ios_base;
1170 
1171       const typename __ios_base::fmtflags __flags = __is.flags();
1172       __is.flags(__ios_base::skipws);
1173 
1174       _IntType __k;
1175       double __p;
1176       __is >> __k >> __p >> __x._M_gd;
1177       __x.param(typename negative_binomial_distribution<_IntType>::
1178 		param_type(__k, __p));
1179 
1180       __is.flags(__flags);
1181       return __is;
1182     }
1183 
1184 
1185   template<typename _IntType>
1186     void
1187     poisson_distribution<_IntType>::param_type::
1188     _M_initialize()
1189     {
1190 #if _GLIBCXX_USE_C99_MATH_TR1
1191       if (_M_mean >= 12)
1192 	{
1193 	  const double __m = std::floor(_M_mean);
1194 	  _M_lm_thr = std::log(_M_mean);
1195 	  _M_lfm = std::lgamma(__m + 1);
1196 	  _M_sm = std::sqrt(__m);
1197 
1198 	  const double __pi_4 = 0.7853981633974483096156608458198757L;
1199 	  const double __dx = std::sqrt(2 * __m * std::log(32 * __m
1200 							      / __pi_4));
1201 	  _M_d = std::round(std::max(6.0, std::min(__m, __dx)));
1202 	  const double __cx = 2 * __m + _M_d;
1203 	  _M_scx = std::sqrt(__cx / 2);
1204 	  _M_1cx = 1 / __cx;
1205 
1206 	  _M_c2b = std::sqrt(__pi_4 * __cx) * std::exp(_M_1cx);
1207 	  _M_cb = 2 * __cx * std::exp(-_M_d * _M_1cx * (1 + _M_d / 2))
1208 		/ _M_d;
1209 	}
1210       else
1211 #endif
1212 	_M_lm_thr = std::exp(-_M_mean);
1213       }
1214 
1215   /**
1216    * A rejection algorithm when mean >= 12 and a simple method based
1217    * upon the multiplication of uniform random variates otherwise.
1218    * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
1219    * is defined.
1220    *
1221    * Reference:
1222    * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1223    * New York, 1986, Ch. X, Sects. 3.3 & 3.4 (+ Errata!).
1224    */
1225   template<typename _IntType>
1226     template<typename _UniformRandomNumberGenerator>
1227       typename poisson_distribution<_IntType>::result_type
1228       poisson_distribution<_IntType>::
1229       operator()(_UniformRandomNumberGenerator& __urng,
1230 		 const param_type& __param)
1231       {
1232 	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
1233 	  __aurng(__urng);
1234 #if _GLIBCXX_USE_C99_MATH_TR1
1235 	if (__param.mean() >= 12)
1236 	  {
1237 	    double __x;
1238 
1239 	    // See comments above...
1240 	    const double __naf =
1241 	      (1 - std::numeric_limits<double>::epsilon()) / 2;
1242 	    const double __thr =
1243 	      std::numeric_limits<_IntType>::max() + __naf;
1244 
1245 	    const double __m = std::floor(__param.mean());
1246 	    // sqrt(pi / 2)
1247 	    const double __spi_2 = 1.2533141373155002512078826424055226L;
1248 	    const double __c1 = __param._M_sm * __spi_2;
1249 	    const double __c2 = __param._M_c2b + __c1;
1250 	    const double __c3 = __c2 + 1;
1251 	    const double __c4 = __c3 + 1;
1252 	    // e^(1 / 78)
1253 	    const double __e178 = 1.0129030479320018583185514777512983L;
1254 	    const double __c5 = __c4 + __e178;
1255 	    const double __c = __param._M_cb + __c5;
1256 	    const double __2cx = 2 * (2 * __m + __param._M_d);
1257 
1258 	    bool __reject = true;
1259 	    do
1260 	      {
1261 		const double __u = __c * __aurng();
1262 		const double __e = -std::log(1.0 - __aurng());
1263 
1264 		double __w = 0.0;
1265 
1266 		if (__u <= __c1)
1267 		  {
1268 		    const double __n = _M_nd(__urng);
1269 		    const double __y = -std::abs(__n) * __param._M_sm - 1;
1270 		    __x = std::floor(__y);
1271 		    __w = -__n * __n / 2;
1272 		    if (__x < -__m)
1273 		      continue;
1274 		  }
1275 		else if (__u <= __c2)
1276 		  {
1277 		    const double __n = _M_nd(__urng);
1278 		    const double __y = 1 + std::abs(__n) * __param._M_scx;
1279 		    __x = std::ceil(__y);
1280 		    __w = __y * (2 - __y) * __param._M_1cx;
1281 		    if (__x > __param._M_d)
1282 		      continue;
1283 		  }
1284 		else if (__u <= __c3)
1285 		  // NB: This case not in the book, nor in the Errata,
1286 		  // but should be ok...
1287 		  __x = -1;
1288 		else if (__u <= __c4)
1289 		  __x = 0;
1290 		else if (__u <= __c5)
1291 		  __x = 1;
1292 		else
1293 		  {
1294 		    const double __v = -std::log(1.0 - __aurng());
1295 		    const double __y = __param._M_d
1296 				     + __v * __2cx / __param._M_d;
1297 		    __x = std::ceil(__y);
1298 		    __w = -__param._M_d * __param._M_1cx * (1 + __y / 2);
1299 		  }
1300 
1301 		__reject = (__w - __e - __x * __param._M_lm_thr
1302 			    > __param._M_lfm - std::lgamma(__x + __m + 1));
1303 
1304 		__reject |= __x + __m >= __thr;
1305 
1306 	      } while (__reject);
1307 
1308 	    return result_type(__x + __m + __naf);
1309 	  }
1310 	else
1311 #endif
1312 	  {
1313 	    _IntType     __x = 0;
1314 	    double __prod = 1.0;
1315 
1316 	    do
1317 	      {
1318 		__prod *= __aurng();
1319 		__x += 1;
1320 	      }
1321 	    while (__prod > __param._M_lm_thr);
1322 
1323 	    return __x - 1;
1324 	  }
1325       }
1326 
1327   template<typename _IntType,
1328 	   typename _CharT, typename _Traits>
1329     std::basic_ostream<_CharT, _Traits>&
1330     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1331 	       const poisson_distribution<_IntType>& __x)
1332     {
1333       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1334       typedef typename __ostream_type::ios_base    __ios_base;
1335 
1336       const typename __ios_base::fmtflags __flags = __os.flags();
1337       const _CharT __fill = __os.fill();
1338       const std::streamsize __precision = __os.precision();
1339       const _CharT __space = __os.widen(' ');
1340       __os.flags(__ios_base::scientific | __ios_base::left);
1341       __os.fill(__space);
1342       __os.precision(std::numeric_limits<double>::max_digits10);
1343 
1344       __os << __x.mean() << __space << __x._M_nd;
1345 
1346       __os.flags(__flags);
1347       __os.fill(__fill);
1348       __os.precision(__precision);
1349       return __os;
1350     }
1351 
1352   template<typename _IntType,
1353 	   typename _CharT, typename _Traits>
1354     std::basic_istream<_CharT, _Traits>&
1355     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1356 	       poisson_distribution<_IntType>& __x)
1357     {
1358       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1359       typedef typename __istream_type::ios_base    __ios_base;
1360 
1361       const typename __ios_base::fmtflags __flags = __is.flags();
1362       __is.flags(__ios_base::skipws);
1363 
1364       double __mean;
1365       __is >> __mean >> __x._M_nd;
1366       __x.param(typename poisson_distribution<_IntType>::param_type(__mean));
1367 
1368       __is.flags(__flags);
1369       return __is;
1370     }
1371 
1372 
1373   template<typename _IntType>
1374     void
1375     binomial_distribution<_IntType>::param_type::
1376     _M_initialize()
1377     {
1378       const double __p12 = _M_p <= 0.5 ? _M_p : 1.0 - _M_p;
1379 
1380       _M_easy = true;
1381 
1382 #if _GLIBCXX_USE_C99_MATH_TR1
1383       if (_M_t * __p12 >= 8)
1384 	{
1385 	  _M_easy = false;
1386 	  const double __np = std::floor(_M_t * __p12);
1387 	  const double __pa = __np / _M_t;
1388 	  const double __1p = 1 - __pa;
1389 
1390 	  const double __pi_4 = 0.7853981633974483096156608458198757L;
1391 	  const double __d1x =
1392 	    std::sqrt(__np * __1p * std::log(32 * __np
1393 					     / (81 * __pi_4 * __1p)));
1394 	  _M_d1 = std::round(std::max(1.0, __d1x));
1395 	  const double __d2x =
1396 	    std::sqrt(__np * __1p * std::log(32 * _M_t * __1p
1397 					     / (__pi_4 * __pa)));
1398 	  _M_d2 = std::round(std::max(1.0, __d2x));
1399 
1400 	  // sqrt(pi / 2)
1401 	  const double __spi_2 = 1.2533141373155002512078826424055226L;
1402 	  _M_s1 = std::sqrt(__np * __1p) * (1 + _M_d1 / (4 * __np));
1403 	  _M_s2 = std::sqrt(__np * __1p) * (1 + _M_d2 / (4 * _M_t * __1p));
1404 	  _M_c = 2 * _M_d1 / __np;
1405 	  _M_a1 = std::exp(_M_c) * _M_s1 * __spi_2;
1406 	  const double __a12 = _M_a1 + _M_s2 * __spi_2;
1407 	  const double __s1s = _M_s1 * _M_s1;
1408 	  _M_a123 = __a12 + (std::exp(_M_d1 / (_M_t * __1p))
1409 			     * 2 * __s1s / _M_d1
1410 			     * std::exp(-_M_d1 * _M_d1 / (2 * __s1s)));
1411 	  const double __s2s = _M_s2 * _M_s2;
1412 	  _M_s = (_M_a123 + 2 * __s2s / _M_d2
1413 		  * std::exp(-_M_d2 * _M_d2 / (2 * __s2s)));
1414 	  _M_lf = (std::lgamma(__np + 1)
1415 		   + std::lgamma(_M_t - __np + 1));
1416 	  _M_lp1p = std::log(__pa / __1p);
1417 
1418 	  _M_q = -std::log(1 - (__p12 - __pa) / __1p);
1419 	}
1420       else
1421 #endif
1422 	_M_q = -std::log(1 - __p12);
1423     }
1424 
1425   template<typename _IntType>
1426     template<typename _UniformRandomNumberGenerator>
1427       typename binomial_distribution<_IntType>::result_type
1428       binomial_distribution<_IntType>::
1429       _M_waiting(_UniformRandomNumberGenerator& __urng, _IntType __t)
1430       {
1431 	_IntType __x = 0;
1432 	double __sum = 0.0;
1433 	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
1434 	  __aurng(__urng);
1435 
1436 	do
1437 	  {
1438 	    const double __e = -std::log(1.0 - __aurng());
1439 	    __sum += __e / (__t - __x);
1440 	    __x += 1;
1441 	  }
1442 	while (__sum <= _M_param._M_q);
1443 
1444 	return __x - 1;
1445       }
1446 
1447   /**
1448    * A rejection algorithm when t * p >= 8 and a simple waiting time
1449    * method - the second in the referenced book - otherwise.
1450    * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
1451    * is defined.
1452    *
1453    * Reference:
1454    * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1455    * New York, 1986, Ch. X, Sect. 4 (+ Errata!).
1456    */
1457   template<typename _IntType>
1458     template<typename _UniformRandomNumberGenerator>
1459       typename binomial_distribution<_IntType>::result_type
1460       binomial_distribution<_IntType>::
1461       operator()(_UniformRandomNumberGenerator& __urng,
1462 		 const param_type& __param)
1463       {
1464 	result_type __ret;
1465 	const _IntType __t = __param.t();
1466 	const double __p = __param.p();
1467 	const double __p12 = __p <= 0.5 ? __p : 1.0 - __p;
1468 	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
1469 	  __aurng(__urng);
1470 
1471 #if _GLIBCXX_USE_C99_MATH_TR1
1472 	if (!__param._M_easy)
1473 	  {
1474 	    double __x;
1475 
1476 	    // See comments above...
1477 	    const double __naf =
1478 	      (1 - std::numeric_limits<double>::epsilon()) / 2;
1479 	    const double __thr =
1480 	      std::numeric_limits<_IntType>::max() + __naf;
1481 
1482 	    const double __np = std::floor(__t * __p12);
1483 
1484 	    // sqrt(pi / 2)
1485 	    const double __spi_2 = 1.2533141373155002512078826424055226L;
1486 	    const double __a1 = __param._M_a1;
1487 	    const double __a12 = __a1 + __param._M_s2 * __spi_2;
1488 	    const double __a123 = __param._M_a123;
1489 	    const double __s1s = __param._M_s1 * __param._M_s1;
1490 	    const double __s2s = __param._M_s2 * __param._M_s2;
1491 
1492 	    bool __reject;
1493 	    do
1494 	      {
1495 		const double __u = __param._M_s * __aurng();
1496 
1497 		double __v;
1498 
1499 		if (__u <= __a1)
1500 		  {
1501 		    const double __n = _M_nd(__urng);
1502 		    const double __y = __param._M_s1 * std::abs(__n);
1503 		    __reject = __y >= __param._M_d1;
1504 		    if (!__reject)
1505 		      {
1506 			const double __e = -std::log(1.0 - __aurng());
1507 			__x = std::floor(__y);
1508 			__v = -__e - __n * __n / 2 + __param._M_c;
1509 		      }
1510 		  }
1511 		else if (__u <= __a12)
1512 		  {
1513 		    const double __n = _M_nd(__urng);
1514 		    const double __y = __param._M_s2 * std::abs(__n);
1515 		    __reject = __y >= __param._M_d2;
1516 		    if (!__reject)
1517 		      {
1518 			const double __e = -std::log(1.0 - __aurng());
1519 			__x = std::floor(-__y);
1520 			__v = -__e - __n * __n / 2;
1521 		      }
1522 		  }
1523 		else if (__u <= __a123)
1524 		  {
1525 		    const double __e1 = -std::log(1.0 - __aurng());
1526 		    const double __e2 = -std::log(1.0 - __aurng());
1527 
1528 		    const double __y = __param._M_d1
1529 				     + 2 * __s1s * __e1 / __param._M_d1;
1530 		    __x = std::floor(__y);
1531 		    __v = (-__e2 + __param._M_d1 * (1 / (__t - __np)
1532 						    -__y / (2 * __s1s)));
1533 		    __reject = false;
1534 		  }
1535 		else
1536 		  {
1537 		    const double __e1 = -std::log(1.0 - __aurng());
1538 		    const double __e2 = -std::log(1.0 - __aurng());
1539 
1540 		    const double __y = __param._M_d2
1541 				     + 2 * __s2s * __e1 / __param._M_d2;
1542 		    __x = std::floor(-__y);
1543 		    __v = -__e2 - __param._M_d2 * __y / (2 * __s2s);
1544 		    __reject = false;
1545 		  }
1546 
1547 		__reject = __reject || __x < -__np || __x > __t - __np;
1548 		if (!__reject)
1549 		  {
1550 		    const double __lfx =
1551 		      std::lgamma(__np + __x + 1)
1552 		      + std::lgamma(__t - (__np + __x) + 1);
1553 		    __reject = __v > __param._M_lf - __lfx
1554 			     + __x * __param._M_lp1p;
1555 		  }
1556 
1557 		__reject |= __x + __np >= __thr;
1558 	      }
1559 	    while (__reject);
1560 
1561 	    __x += __np + __naf;
1562 
1563 	    const _IntType __z = _M_waiting(__urng, __t - _IntType(__x));
1564 	    __ret = _IntType(__x) + __z;
1565 	  }
1566 	else
1567 #endif
1568 	  __ret = _M_waiting(__urng, __t);
1569 
1570 	if (__p12 != __p)
1571 	  __ret = __t - __ret;
1572 	return __ret;
1573       }
1574 
1575   template<typename _IntType,
1576 	   typename _CharT, typename _Traits>
1577     std::basic_ostream<_CharT, _Traits>&
1578     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1579 	       const binomial_distribution<_IntType>& __x)
1580     {
1581       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1582       typedef typename __ostream_type::ios_base    __ios_base;
1583 
1584       const typename __ios_base::fmtflags __flags = __os.flags();
1585       const _CharT __fill = __os.fill();
1586       const std::streamsize __precision = __os.precision();
1587       const _CharT __space = __os.widen(' ');
1588       __os.flags(__ios_base::scientific | __ios_base::left);
1589       __os.fill(__space);
1590       __os.precision(std::numeric_limits<double>::max_digits10);
1591 
1592       __os << __x.t() << __space << __x.p()
1593 	   << __space << __x._M_nd;
1594 
1595       __os.flags(__flags);
1596       __os.fill(__fill);
1597       __os.precision(__precision);
1598       return __os;
1599     }
1600 
1601   template<typename _IntType,
1602 	   typename _CharT, typename _Traits>
1603     std::basic_istream<_CharT, _Traits>&
1604     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1605 	       binomial_distribution<_IntType>& __x)
1606     {
1607       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1608       typedef typename __istream_type::ios_base    __ios_base;
1609 
1610       const typename __ios_base::fmtflags __flags = __is.flags();
1611       __is.flags(__ios_base::dec | __ios_base::skipws);
1612 
1613       _IntType __t;
1614       double __p;
1615       __is >> __t >> __p >> __x._M_nd;
1616       __x.param(typename binomial_distribution<_IntType>::
1617 		param_type(__t, __p));
1618 
1619       __is.flags(__flags);
1620       return __is;
1621     }
1622 
1623 
1624   template<typename _RealType, typename _CharT, typename _Traits>
1625     std::basic_ostream<_CharT, _Traits>&
1626     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1627 	       const exponential_distribution<_RealType>& __x)
1628     {
1629       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1630       typedef typename __ostream_type::ios_base    __ios_base;
1631 
1632       const typename __ios_base::fmtflags __flags = __os.flags();
1633       const _CharT __fill = __os.fill();
1634       const std::streamsize __precision = __os.precision();
1635       __os.flags(__ios_base::scientific | __ios_base::left);
1636       __os.fill(__os.widen(' '));
1637       __os.precision(std::numeric_limits<_RealType>::max_digits10);
1638 
1639       __os << __x.lambda();
1640 
1641       __os.flags(__flags);
1642       __os.fill(__fill);
1643       __os.precision(__precision);
1644       return __os;
1645     }
1646 
1647   template<typename _RealType, typename _CharT, typename _Traits>
1648     std::basic_istream<_CharT, _Traits>&
1649     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1650 	       exponential_distribution<_RealType>& __x)
1651     {
1652       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1653       typedef typename __istream_type::ios_base    __ios_base;
1654 
1655       const typename __ios_base::fmtflags __flags = __is.flags();
1656       __is.flags(__ios_base::dec | __ios_base::skipws);
1657 
1658       _RealType __lambda;
1659       __is >> __lambda;
1660       __x.param(typename exponential_distribution<_RealType>::
1661 		param_type(__lambda));
1662 
1663       __is.flags(__flags);
1664       return __is;
1665     }
1666 
1667 
1668   /**
1669    * Polar method due to Marsaglia.
1670    *
1671    * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
1672    * New York, 1986, Ch. V, Sect. 4.4.
1673    */
1674   template<typename _RealType>
1675     template<typename _UniformRandomNumberGenerator>
1676       typename normal_distribution<_RealType>::result_type
1677       normal_distribution<_RealType>::
1678       operator()(_UniformRandomNumberGenerator& __urng,
1679 		 const param_type& __param)
1680       {
1681 	result_type __ret;
1682 	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
1683 	  __aurng(__urng);
1684 
1685 	if (_M_saved_available)
1686 	  {
1687 	    _M_saved_available = false;
1688 	    __ret = _M_saved;
1689 	  }
1690 	else
1691 	  {
1692 	    result_type __x, __y, __r2;
1693 	    do
1694 	      {
1695 		__x = result_type(2.0) * __aurng() - 1.0;
1696 		__y = result_type(2.0) * __aurng() - 1.0;
1697 		__r2 = __x * __x + __y * __y;
1698 	      }
1699 	    while (__r2 > 1.0 || __r2 == 0.0);
1700 
1701 	    const result_type __mult = std::sqrt(-2 * std::log(__r2) / __r2);
1702 	    _M_saved = __x * __mult;
1703 	    _M_saved_available = true;
1704 	    __ret = __y * __mult;
1705 	  }
1706 
1707 	__ret = __ret * __param.stddev() + __param.mean();
1708 	return __ret;
1709       }
1710 
1711   template<typename _RealType>
1712     bool
1713     operator==(const std::normal_distribution<_RealType>& __d1,
1714 	       const std::normal_distribution<_RealType>& __d2)
1715     {
1716       if (__d1._M_param == __d2._M_param
1717 	  && __d1._M_saved_available == __d2._M_saved_available)
1718 	{
1719 	  if (__d1._M_saved_available
1720 	      && __d1._M_saved == __d2._M_saved)
1721 	    return true;
1722 	  else if(!__d1._M_saved_available)
1723 	    return true;
1724 	  else
1725 	    return false;
1726 	}
1727       else
1728 	return false;
1729     }
1730 
1731   template<typename _RealType, typename _CharT, typename _Traits>
1732     std::basic_ostream<_CharT, _Traits>&
1733     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1734 	       const normal_distribution<_RealType>& __x)
1735     {
1736       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1737       typedef typename __ostream_type::ios_base    __ios_base;
1738 
1739       const typename __ios_base::fmtflags __flags = __os.flags();
1740       const _CharT __fill = __os.fill();
1741       const std::streamsize __precision = __os.precision();
1742       const _CharT __space = __os.widen(' ');
1743       __os.flags(__ios_base::scientific | __ios_base::left);
1744       __os.fill(__space);
1745       __os.precision(std::numeric_limits<_RealType>::max_digits10);
1746 
1747       __os << __x.mean() << __space << __x.stddev()
1748 	   << __space << __x._M_saved_available;
1749       if (__x._M_saved_available)
1750 	__os << __space << __x._M_saved;
1751 
1752       __os.flags(__flags);
1753       __os.fill(__fill);
1754       __os.precision(__precision);
1755       return __os;
1756     }
1757 
1758   template<typename _RealType, typename _CharT, typename _Traits>
1759     std::basic_istream<_CharT, _Traits>&
1760     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1761 	       normal_distribution<_RealType>& __x)
1762     {
1763       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1764       typedef typename __istream_type::ios_base    __ios_base;
1765 
1766       const typename __ios_base::fmtflags __flags = __is.flags();
1767       __is.flags(__ios_base::dec | __ios_base::skipws);
1768 
1769       double __mean, __stddev;
1770       __is >> __mean >> __stddev
1771 	   >> __x._M_saved_available;
1772       if (__x._M_saved_available)
1773 	__is >> __x._M_saved;
1774       __x.param(typename normal_distribution<_RealType>::
1775 		param_type(__mean, __stddev));
1776 
1777       __is.flags(__flags);
1778       return __is;
1779     }
1780 
1781 
1782   template<typename _RealType, typename _CharT, typename _Traits>
1783     std::basic_ostream<_CharT, _Traits>&
1784     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1785 	       const lognormal_distribution<_RealType>& __x)
1786     {
1787       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1788       typedef typename __ostream_type::ios_base    __ios_base;
1789 
1790       const typename __ios_base::fmtflags __flags = __os.flags();
1791       const _CharT __fill = __os.fill();
1792       const std::streamsize __precision = __os.precision();
1793       const _CharT __space = __os.widen(' ');
1794       __os.flags(__ios_base::scientific | __ios_base::left);
1795       __os.fill(__space);
1796       __os.precision(std::numeric_limits<_RealType>::max_digits10);
1797 
1798       __os << __x.m() << __space << __x.s()
1799 	   << __space << __x._M_nd;
1800 
1801       __os.flags(__flags);
1802       __os.fill(__fill);
1803       __os.precision(__precision);
1804       return __os;
1805     }
1806 
1807   template<typename _RealType, typename _CharT, typename _Traits>
1808     std::basic_istream<_CharT, _Traits>&
1809     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1810 	       lognormal_distribution<_RealType>& __x)
1811     {
1812       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1813       typedef typename __istream_type::ios_base    __ios_base;
1814 
1815       const typename __ios_base::fmtflags __flags = __is.flags();
1816       __is.flags(__ios_base::dec | __ios_base::skipws);
1817 
1818       _RealType __m, __s;
1819       __is >> __m >> __s >> __x._M_nd;
1820       __x.param(typename lognormal_distribution<_RealType>::
1821 		param_type(__m, __s));
1822 
1823       __is.flags(__flags);
1824       return __is;
1825     }
1826 
1827 
1828   template<typename _RealType, typename _CharT, typename _Traits>
1829     std::basic_ostream<_CharT, _Traits>&
1830     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1831 	       const chi_squared_distribution<_RealType>& __x)
1832     {
1833       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1834       typedef typename __ostream_type::ios_base    __ios_base;
1835 
1836       const typename __ios_base::fmtflags __flags = __os.flags();
1837       const _CharT __fill = __os.fill();
1838       const std::streamsize __precision = __os.precision();
1839       const _CharT __space = __os.widen(' ');
1840       __os.flags(__ios_base::scientific | __ios_base::left);
1841       __os.fill(__space);
1842       __os.precision(std::numeric_limits<_RealType>::max_digits10);
1843 
1844       __os << __x.n() << __space << __x._M_gd;
1845 
1846       __os.flags(__flags);
1847       __os.fill(__fill);
1848       __os.precision(__precision);
1849       return __os;
1850     }
1851 
1852   template<typename _RealType, typename _CharT, typename _Traits>
1853     std::basic_istream<_CharT, _Traits>&
1854     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1855 	       chi_squared_distribution<_RealType>& __x)
1856     {
1857       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1858       typedef typename __istream_type::ios_base    __ios_base;
1859 
1860       const typename __ios_base::fmtflags __flags = __is.flags();
1861       __is.flags(__ios_base::dec | __ios_base::skipws);
1862 
1863       _RealType __n;
1864       __is >> __n >> __x._M_gd;
1865       __x.param(typename chi_squared_distribution<_RealType>::
1866 		param_type(__n));
1867 
1868       __is.flags(__flags);
1869       return __is;
1870     }
1871 
1872 
1873   template<typename _RealType>
1874     template<typename _UniformRandomNumberGenerator>
1875       typename cauchy_distribution<_RealType>::result_type
1876       cauchy_distribution<_RealType>::
1877       operator()(_UniformRandomNumberGenerator& __urng,
1878 		 const param_type& __p)
1879       {
1880 	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
1881 	  __aurng(__urng);
1882 	_RealType __u;
1883 	do
1884 	  __u = __aurng();
1885 	while (__u == 0.5);
1886 
1887 	const _RealType __pi = 3.1415926535897932384626433832795029L;
1888 	return __p.a() + __p.b() * std::tan(__pi * __u);
1889       }
1890 
1891   template<typename _RealType, typename _CharT, typename _Traits>
1892     std::basic_ostream<_CharT, _Traits>&
1893     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1894 	       const cauchy_distribution<_RealType>& __x)
1895     {
1896       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1897       typedef typename __ostream_type::ios_base    __ios_base;
1898 
1899       const typename __ios_base::fmtflags __flags = __os.flags();
1900       const _CharT __fill = __os.fill();
1901       const std::streamsize __precision = __os.precision();
1902       const _CharT __space = __os.widen(' ');
1903       __os.flags(__ios_base::scientific | __ios_base::left);
1904       __os.fill(__space);
1905       __os.precision(std::numeric_limits<_RealType>::max_digits10);
1906 
1907       __os << __x.a() << __space << __x.b();
1908 
1909       __os.flags(__flags);
1910       __os.fill(__fill);
1911       __os.precision(__precision);
1912       return __os;
1913     }
1914 
1915   template<typename _RealType, typename _CharT, typename _Traits>
1916     std::basic_istream<_CharT, _Traits>&
1917     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1918 	       cauchy_distribution<_RealType>& __x)
1919     {
1920       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1921       typedef typename __istream_type::ios_base    __ios_base;
1922 
1923       const typename __ios_base::fmtflags __flags = __is.flags();
1924       __is.flags(__ios_base::dec | __ios_base::skipws);
1925 
1926       _RealType __a, __b;
1927       __is >> __a >> __b;
1928       __x.param(typename cauchy_distribution<_RealType>::
1929 		param_type(__a, __b));
1930 
1931       __is.flags(__flags);
1932       return __is;
1933     }
1934 
1935 
1936   template<typename _RealType, typename _CharT, typename _Traits>
1937     std::basic_ostream<_CharT, _Traits>&
1938     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1939 	       const fisher_f_distribution<_RealType>& __x)
1940     {
1941       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1942       typedef typename __ostream_type::ios_base    __ios_base;
1943 
1944       const typename __ios_base::fmtflags __flags = __os.flags();
1945       const _CharT __fill = __os.fill();
1946       const std::streamsize __precision = __os.precision();
1947       const _CharT __space = __os.widen(' ');
1948       __os.flags(__ios_base::scientific | __ios_base::left);
1949       __os.fill(__space);
1950       __os.precision(std::numeric_limits<_RealType>::max_digits10);
1951 
1952       __os << __x.m() << __space << __x.n()
1953 	   << __space << __x._M_gd_x << __space << __x._M_gd_y;
1954 
1955       __os.flags(__flags);
1956       __os.fill(__fill);
1957       __os.precision(__precision);
1958       return __os;
1959     }
1960 
1961   template<typename _RealType, typename _CharT, typename _Traits>
1962     std::basic_istream<_CharT, _Traits>&
1963     operator>>(std::basic_istream<_CharT, _Traits>& __is,
1964 	       fisher_f_distribution<_RealType>& __x)
1965     {
1966       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
1967       typedef typename __istream_type::ios_base    __ios_base;
1968 
1969       const typename __ios_base::fmtflags __flags = __is.flags();
1970       __is.flags(__ios_base::dec | __ios_base::skipws);
1971 
1972       _RealType __m, __n;
1973       __is >> __m >> __n >> __x._M_gd_x >> __x._M_gd_y;
1974       __x.param(typename fisher_f_distribution<_RealType>::
1975 		param_type(__m, __n));
1976 
1977       __is.flags(__flags);
1978       return __is;
1979     }
1980 
1981 
1982   template<typename _RealType, typename _CharT, typename _Traits>
1983     std::basic_ostream<_CharT, _Traits>&
1984     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
1985 	       const student_t_distribution<_RealType>& __x)
1986     {
1987       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
1988       typedef typename __ostream_type::ios_base    __ios_base;
1989 
1990       const typename __ios_base::fmtflags __flags = __os.flags();
1991       const _CharT __fill = __os.fill();
1992       const std::streamsize __precision = __os.precision();
1993       const _CharT __space = __os.widen(' ');
1994       __os.flags(__ios_base::scientific | __ios_base::left);
1995       __os.fill(__space);
1996       __os.precision(std::numeric_limits<_RealType>::max_digits10);
1997 
1998       __os << __x.n() << __space << __x._M_nd << __space << __x._M_gd;
1999 
2000       __os.flags(__flags);
2001       __os.fill(__fill);
2002       __os.precision(__precision);
2003       return __os;
2004     }
2005 
2006   template<typename _RealType, typename _CharT, typename _Traits>
2007     std::basic_istream<_CharT, _Traits>&
2008     operator>>(std::basic_istream<_CharT, _Traits>& __is,
2009 	       student_t_distribution<_RealType>& __x)
2010     {
2011       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
2012       typedef typename __istream_type::ios_base    __ios_base;
2013 
2014       const typename __ios_base::fmtflags __flags = __is.flags();
2015       __is.flags(__ios_base::dec | __ios_base::skipws);
2016 
2017       _RealType __n;
2018       __is >> __n >> __x._M_nd >> __x._M_gd;
2019       __x.param(typename student_t_distribution<_RealType>::param_type(__n));
2020 
2021       __is.flags(__flags);
2022       return __is;
2023     }
2024 
2025 
2026   template<typename _RealType>
2027     void
2028     gamma_distribution<_RealType>::param_type::
2029     _M_initialize()
2030     {
2031       _M_malpha = _M_alpha < 1.0 ? _M_alpha + _RealType(1.0) : _M_alpha;
2032 
2033       const _RealType __a1 = _M_malpha - _RealType(1.0) / _RealType(3.0);
2034       _M_a2 = _RealType(1.0) / std::sqrt(_RealType(9.0) * __a1);
2035     }
2036 
2037   /**
2038    * Marsaglia, G. and Tsang, W. W.
2039    * "A Simple Method for Generating Gamma Variables"
2040    * ACM Transactions on Mathematical Software, 26, 3, 363-372, 2000.
2041    */
2042   template<typename _RealType>
2043     template<typename _UniformRandomNumberGenerator>
2044       typename gamma_distribution<_RealType>::result_type
2045       gamma_distribution<_RealType>::
2046       operator()(_UniformRandomNumberGenerator& __urng,
2047 		 const param_type& __param)
2048       {
2049 	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
2050 	  __aurng(__urng);
2051 
2052 	result_type __u, __v, __n;
2053 	const result_type __a1 = (__param._M_malpha
2054 				  - _RealType(1.0) / _RealType(3.0));
2055 
2056 	do
2057 	  {
2058 	    do
2059 	      {
2060 		__n = _M_nd(__urng);
2061 		__v = result_type(1.0) + __param._M_a2 * __n;
2062 	      }
2063 	    while (__v <= 0.0);
2064 
2065 	    __v = __v * __v * __v;
2066 	    __u = __aurng();
2067 	  }
2068 	while (__u > result_type(1.0) - 0.331 * __n * __n * __n * __n
2069 	       && (std::log(__u) > (0.5 * __n * __n + __a1
2070 				    * (1.0 - __v + std::log(__v)))));
2071 
2072 	if (__param.alpha() == __param._M_malpha)
2073 	  return __a1 * __v * __param.beta();
2074 	else
2075 	  {
2076 	    do
2077 	      __u = __aurng();
2078 	    while (__u == 0.0);
2079 
2080 	    return (std::pow(__u, result_type(1.0) / __param.alpha())
2081 		    * __a1 * __v * __param.beta());
2082 	  }
2083       }
2084 
2085   template<typename _RealType, typename _CharT, typename _Traits>
2086     std::basic_ostream<_CharT, _Traits>&
2087     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
2088 	       const gamma_distribution<_RealType>& __x)
2089     {
2090       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
2091       typedef typename __ostream_type::ios_base    __ios_base;
2092 
2093       const typename __ios_base::fmtflags __flags = __os.flags();
2094       const _CharT __fill = __os.fill();
2095       const std::streamsize __precision = __os.precision();
2096       const _CharT __space = __os.widen(' ');
2097       __os.flags(__ios_base::scientific | __ios_base::left);
2098       __os.fill(__space);
2099       __os.precision(std::numeric_limits<_RealType>::max_digits10);
2100 
2101       __os << __x.alpha() << __space << __x.beta()
2102 	   << __space << __x._M_nd;
2103 
2104       __os.flags(__flags);
2105       __os.fill(__fill);
2106       __os.precision(__precision);
2107       return __os;
2108     }
2109 
2110   template<typename _RealType, typename _CharT, typename _Traits>
2111     std::basic_istream<_CharT, _Traits>&
2112     operator>>(std::basic_istream<_CharT, _Traits>& __is,
2113 	       gamma_distribution<_RealType>& __x)
2114     {
2115       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
2116       typedef typename __istream_type::ios_base    __ios_base;
2117 
2118       const typename __ios_base::fmtflags __flags = __is.flags();
2119       __is.flags(__ios_base::dec | __ios_base::skipws);
2120 
2121       _RealType __alpha_val, __beta_val;
2122       __is >> __alpha_val >> __beta_val >> __x._M_nd;
2123       __x.param(typename gamma_distribution<_RealType>::
2124 		param_type(__alpha_val, __beta_val));
2125 
2126       __is.flags(__flags);
2127       return __is;
2128     }
2129 
2130 
2131   template<typename _RealType>
2132     template<typename _UniformRandomNumberGenerator>
2133       typename weibull_distribution<_RealType>::result_type
2134       weibull_distribution<_RealType>::
2135       operator()(_UniformRandomNumberGenerator& __urng,
2136 		 const param_type& __p)
2137       {
2138 	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
2139 	  __aurng(__urng);
2140 	return __p.b() * std::pow(-std::log(result_type(1) - __aurng()),
2141 				  result_type(1) / __p.a());
2142       }
2143 
2144   template<typename _RealType, typename _CharT, typename _Traits>
2145     std::basic_ostream<_CharT, _Traits>&
2146     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
2147 	       const weibull_distribution<_RealType>& __x)
2148     {
2149       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
2150       typedef typename __ostream_type::ios_base    __ios_base;
2151 
2152       const typename __ios_base::fmtflags __flags = __os.flags();
2153       const _CharT __fill = __os.fill();
2154       const std::streamsize __precision = __os.precision();
2155       const _CharT __space = __os.widen(' ');
2156       __os.flags(__ios_base::scientific | __ios_base::left);
2157       __os.fill(__space);
2158       __os.precision(std::numeric_limits<_RealType>::max_digits10);
2159 
2160       __os << __x.a() << __space << __x.b();
2161 
2162       __os.flags(__flags);
2163       __os.fill(__fill);
2164       __os.precision(__precision);
2165       return __os;
2166     }
2167 
2168   template<typename _RealType, typename _CharT, typename _Traits>
2169     std::basic_istream<_CharT, _Traits>&
2170     operator>>(std::basic_istream<_CharT, _Traits>& __is,
2171 	       weibull_distribution<_RealType>& __x)
2172     {
2173       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
2174       typedef typename __istream_type::ios_base    __ios_base;
2175 
2176       const typename __ios_base::fmtflags __flags = __is.flags();
2177       __is.flags(__ios_base::dec | __ios_base::skipws);
2178 
2179       _RealType __a, __b;
2180       __is >> __a >> __b;
2181       __x.param(typename weibull_distribution<_RealType>::
2182 		param_type(__a, __b));
2183 
2184       __is.flags(__flags);
2185       return __is;
2186     }
2187 
2188 
2189   template<typename _RealType>
2190     template<typename _UniformRandomNumberGenerator>
2191       typename extreme_value_distribution<_RealType>::result_type
2192       extreme_value_distribution<_RealType>::
2193       operator()(_UniformRandomNumberGenerator& __urng,
2194 		 const param_type& __p)
2195       {
2196 	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
2197 	  __aurng(__urng);
2198 	return __p.a() - __p.b() * std::log(-std::log(result_type(1)
2199 						      - __aurng()));
2200       }
2201 
2202   template<typename _RealType, typename _CharT, typename _Traits>
2203     std::basic_ostream<_CharT, _Traits>&
2204     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
2205 	       const extreme_value_distribution<_RealType>& __x)
2206     {
2207       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
2208       typedef typename __ostream_type::ios_base    __ios_base;
2209 
2210       const typename __ios_base::fmtflags __flags = __os.flags();
2211       const _CharT __fill = __os.fill();
2212       const std::streamsize __precision = __os.precision();
2213       const _CharT __space = __os.widen(' ');
2214       __os.flags(__ios_base::scientific | __ios_base::left);
2215       __os.fill(__space);
2216       __os.precision(std::numeric_limits<_RealType>::max_digits10);
2217 
2218       __os << __x.a() << __space << __x.b();
2219 
2220       __os.flags(__flags);
2221       __os.fill(__fill);
2222       __os.precision(__precision);
2223       return __os;
2224     }
2225 
2226   template<typename _RealType, typename _CharT, typename _Traits>
2227     std::basic_istream<_CharT, _Traits>&
2228     operator>>(std::basic_istream<_CharT, _Traits>& __is,
2229 	       extreme_value_distribution<_RealType>& __x)
2230     {
2231       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
2232       typedef typename __istream_type::ios_base    __ios_base;
2233 
2234       const typename __ios_base::fmtflags __flags = __is.flags();
2235       __is.flags(__ios_base::dec | __ios_base::skipws);
2236 
2237       _RealType __a, __b;
2238       __is >> __a >> __b;
2239       __x.param(typename extreme_value_distribution<_RealType>::
2240 		param_type(__a, __b));
2241 
2242       __is.flags(__flags);
2243       return __is;
2244     }
2245 
2246 
2247   template<typename _IntType>
2248     void
2249     discrete_distribution<_IntType>::param_type::
2250     _M_initialize()
2251     {
2252       if (_M_prob.size() < 2)
2253 	{
2254 	  _M_prob.clear();
2255 	  return;
2256 	}
2257 
2258       const double __sum = std::accumulate(_M_prob.begin(),
2259 					   _M_prob.end(), 0.0);
2260       // Now normalize the probabilites.
2261       __detail::__transform(_M_prob.begin(), _M_prob.end(), _M_prob.begin(),
2262 			  std::bind2nd(std::divides<double>(), __sum));
2263       // Accumulate partial sums.
2264       _M_cp.reserve(_M_prob.size());
2265       std::partial_sum(_M_prob.begin(), _M_prob.end(),
2266 		       std::back_inserter(_M_cp));
2267       // Make sure the last cumulative probability is one.
2268       _M_cp[_M_cp.size() - 1] = 1.0;
2269     }
2270 
2271   template<typename _IntType>
2272     template<typename _Func>
2273       discrete_distribution<_IntType>::param_type::
2274       param_type(size_t __nw, double __xmin, double __xmax, _Func __fw)
2275       : _M_prob(), _M_cp()
2276       {
2277 	const size_t __n = __nw == 0 ? 1 : __nw;
2278 	const double __delta = (__xmax - __xmin) / __n;
2279 
2280 	_M_prob.reserve(__n);
2281 	for (size_t __k = 0; __k < __nw; ++__k)
2282 	  _M_prob.push_back(__fw(__xmin + __k * __delta + 0.5 * __delta));
2283 
2284 	_M_initialize();
2285       }
2286 
2287   template<typename _IntType>
2288     template<typename _UniformRandomNumberGenerator>
2289       typename discrete_distribution<_IntType>::result_type
2290       discrete_distribution<_IntType>::
2291       operator()(_UniformRandomNumberGenerator& __urng,
2292 		 const param_type& __param)
2293       {
2294 	if (__param._M_cp.empty())
2295 	  return result_type(0);
2296 
2297 	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
2298 	  __aurng(__urng);
2299 
2300 	const double __p = __aurng();
2301 	auto __pos = std::lower_bound(__param._M_cp.begin(),
2302 				      __param._M_cp.end(), __p);
2303 
2304 	return __pos - __param._M_cp.begin();
2305       }
2306 
2307   template<typename _IntType, typename _CharT, typename _Traits>
2308     std::basic_ostream<_CharT, _Traits>&
2309     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
2310 	       const discrete_distribution<_IntType>& __x)
2311     {
2312       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
2313       typedef typename __ostream_type::ios_base    __ios_base;
2314 
2315       const typename __ios_base::fmtflags __flags = __os.flags();
2316       const _CharT __fill = __os.fill();
2317       const std::streamsize __precision = __os.precision();
2318       const _CharT __space = __os.widen(' ');
2319       __os.flags(__ios_base::scientific | __ios_base::left);
2320       __os.fill(__space);
2321       __os.precision(std::numeric_limits<double>::max_digits10);
2322 
2323       std::vector<double> __prob = __x.probabilities();
2324       __os << __prob.size();
2325       for (auto __dit = __prob.begin(); __dit != __prob.end(); ++__dit)
2326 	__os << __space << *__dit;
2327 
2328       __os.flags(__flags);
2329       __os.fill(__fill);
2330       __os.precision(__precision);
2331       return __os;
2332     }
2333 
2334   template<typename _IntType, typename _CharT, typename _Traits>
2335     std::basic_istream<_CharT, _Traits>&
2336     operator>>(std::basic_istream<_CharT, _Traits>& __is,
2337 	       discrete_distribution<_IntType>& __x)
2338     {
2339       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
2340       typedef typename __istream_type::ios_base    __ios_base;
2341 
2342       const typename __ios_base::fmtflags __flags = __is.flags();
2343       __is.flags(__ios_base::dec | __ios_base::skipws);
2344 
2345       size_t __n;
2346       __is >> __n;
2347 
2348       std::vector<double> __prob_vec;
2349       __prob_vec.reserve(__n);
2350       for (; __n != 0; --__n)
2351 	{
2352 	  double __prob;
2353 	  __is >> __prob;
2354 	  __prob_vec.push_back(__prob);
2355 	}
2356 
2357       __x.param(typename discrete_distribution<_IntType>::
2358 		param_type(__prob_vec.begin(), __prob_vec.end()));
2359 
2360       __is.flags(__flags);
2361       return __is;
2362     }
2363 
2364 
2365   template<typename _RealType>
2366     void
2367     piecewise_constant_distribution<_RealType>::param_type::
2368     _M_initialize()
2369     {
2370       if (_M_int.size() < 2
2371 	  || (_M_int.size() == 2
2372 	      && _M_int[0] == _RealType(0)
2373 	      && _M_int[1] == _RealType(1)))
2374 	{
2375 	  _M_int.clear();
2376 	  _M_den.clear();
2377 	  return;
2378 	}
2379 
2380       const double __sum = std::accumulate(_M_den.begin(),
2381 					   _M_den.end(), 0.0);
2382 
2383       __detail::__transform(_M_den.begin(), _M_den.end(), _M_den.begin(),
2384 			    std::bind2nd(std::divides<double>(), __sum));
2385 
2386       _M_cp.reserve(_M_den.size());
2387       std::partial_sum(_M_den.begin(), _M_den.end(),
2388 		       std::back_inserter(_M_cp));
2389 
2390       // Make sure the last cumulative probability is one.
2391       _M_cp[_M_cp.size() - 1] = 1.0;
2392 
2393       for (size_t __k = 0; __k < _M_den.size(); ++__k)
2394 	_M_den[__k] /= _M_int[__k + 1] - _M_int[__k];
2395     }
2396 
2397   template<typename _RealType>
2398     template<typename _InputIteratorB, typename _InputIteratorW>
2399       piecewise_constant_distribution<_RealType>::param_type::
2400       param_type(_InputIteratorB __bbegin,
2401 		 _InputIteratorB __bend,
2402 		 _InputIteratorW __wbegin)
2403       : _M_int(), _M_den(), _M_cp()
2404       {
2405 	if (__bbegin != __bend)
2406 	  {
2407 	    for (;;)
2408 	      {
2409 		_M_int.push_back(*__bbegin);
2410 		++__bbegin;
2411 		if (__bbegin == __bend)
2412 		  break;
2413 
2414 		_M_den.push_back(*__wbegin);
2415 		++__wbegin;
2416 	      }
2417 	  }
2418 
2419 	_M_initialize();
2420       }
2421 
2422   template<typename _RealType>
2423     template<typename _Func>
2424       piecewise_constant_distribution<_RealType>::param_type::
2425       param_type(initializer_list<_RealType> __bl, _Func __fw)
2426       : _M_int(), _M_den(), _M_cp()
2427       {
2428 	_M_int.reserve(__bl.size());
2429 	for (auto __biter = __bl.begin(); __biter != __bl.end(); ++__biter)
2430 	  _M_int.push_back(*__biter);
2431 
2432 	_M_den.reserve(_M_int.size() - 1);
2433 	for (size_t __k = 0; __k < _M_int.size() - 1; ++__k)
2434 	  _M_den.push_back(__fw(0.5 * (_M_int[__k + 1] + _M_int[__k])));
2435 
2436 	_M_initialize();
2437       }
2438 
2439   template<typename _RealType>
2440     template<typename _Func>
2441       piecewise_constant_distribution<_RealType>::param_type::
2442       param_type(size_t __nw, _RealType __xmin, _RealType __xmax, _Func __fw)
2443       : _M_int(), _M_den(), _M_cp()
2444       {
2445 	const size_t __n = __nw == 0 ? 1 : __nw;
2446 	const _RealType __delta = (__xmax - __xmin) / __n;
2447 
2448 	_M_int.reserve(__n + 1);
2449 	for (size_t __k = 0; __k <= __nw; ++__k)
2450 	  _M_int.push_back(__xmin + __k * __delta);
2451 
2452 	_M_den.reserve(__n);
2453 	for (size_t __k = 0; __k < __nw; ++__k)
2454 	  _M_den.push_back(__fw(_M_int[__k] + 0.5 * __delta));
2455 
2456 	_M_initialize();
2457       }
2458 
2459   template<typename _RealType>
2460     template<typename _UniformRandomNumberGenerator>
2461       typename piecewise_constant_distribution<_RealType>::result_type
2462       piecewise_constant_distribution<_RealType>::
2463       operator()(_UniformRandomNumberGenerator& __urng,
2464 		 const param_type& __param)
2465       {
2466 	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
2467 	  __aurng(__urng);
2468 
2469 	const double __p = __aurng();
2470 	if (__param._M_cp.empty())
2471 	  return __p;
2472 
2473 	auto __pos = std::lower_bound(__param._M_cp.begin(),
2474 				      __param._M_cp.end(), __p);
2475 	const size_t __i = __pos - __param._M_cp.begin();
2476 
2477 	const double __pref = __i > 0 ? __param._M_cp[__i - 1] : 0.0;
2478 
2479 	return __param._M_int[__i] + (__p - __pref) / __param._M_den[__i];
2480       }
2481 
2482   template<typename _RealType, typename _CharT, typename _Traits>
2483     std::basic_ostream<_CharT, _Traits>&
2484     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
2485 	       const piecewise_constant_distribution<_RealType>& __x)
2486     {
2487       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
2488       typedef typename __ostream_type::ios_base    __ios_base;
2489 
2490       const typename __ios_base::fmtflags __flags = __os.flags();
2491       const _CharT __fill = __os.fill();
2492       const std::streamsize __precision = __os.precision();
2493       const _CharT __space = __os.widen(' ');
2494       __os.flags(__ios_base::scientific | __ios_base::left);
2495       __os.fill(__space);
2496       __os.precision(std::numeric_limits<_RealType>::max_digits10);
2497 
2498       std::vector<_RealType> __int = __x.intervals();
2499       __os << __int.size() - 1;
2500 
2501       for (auto __xit = __int.begin(); __xit != __int.end(); ++__xit)
2502 	__os << __space << *__xit;
2503 
2504       std::vector<double> __den = __x.densities();
2505       for (auto __dit = __den.begin(); __dit != __den.end(); ++__dit)
2506 	__os << __space << *__dit;
2507 
2508       __os.flags(__flags);
2509       __os.fill(__fill);
2510       __os.precision(__precision);
2511       return __os;
2512     }
2513 
2514   template<typename _RealType, typename _CharT, typename _Traits>
2515     std::basic_istream<_CharT, _Traits>&
2516     operator>>(std::basic_istream<_CharT, _Traits>& __is,
2517 	       piecewise_constant_distribution<_RealType>& __x)
2518     {
2519       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
2520       typedef typename __istream_type::ios_base    __ios_base;
2521 
2522       const typename __ios_base::fmtflags __flags = __is.flags();
2523       __is.flags(__ios_base::dec | __ios_base::skipws);
2524 
2525       size_t __n;
2526       __is >> __n;
2527 
2528       std::vector<_RealType> __int_vec;
2529       __int_vec.reserve(__n + 1);
2530       for (size_t __i = 0; __i <= __n; ++__i)
2531 	{
2532 	  _RealType __int;
2533 	  __is >> __int;
2534 	  __int_vec.push_back(__int);
2535 	}
2536 
2537       std::vector<double> __den_vec;
2538       __den_vec.reserve(__n);
2539       for (size_t __i = 0; __i < __n; ++__i)
2540 	{
2541 	  double __den;
2542 	  __is >> __den;
2543 	  __den_vec.push_back(__den);
2544 	}
2545 
2546       __x.param(typename piecewise_constant_distribution<_RealType>::
2547 	  param_type(__int_vec.begin(), __int_vec.end(), __den_vec.begin()));
2548 
2549       __is.flags(__flags);
2550       return __is;
2551     }
2552 
2553 
2554   template<typename _RealType>
2555     void
2556     piecewise_linear_distribution<_RealType>::param_type::
2557     _M_initialize()
2558     {
2559       if (_M_int.size() < 2
2560 	  || (_M_int.size() == 2
2561 	      && _M_int[0] == _RealType(0)
2562 	      && _M_int[1] == _RealType(1)
2563 	      && _M_den[0] == _M_den[1]))
2564 	{
2565 	  _M_int.clear();
2566 	  _M_den.clear();
2567 	  return;
2568 	}
2569 
2570       double __sum = 0.0;
2571       _M_cp.reserve(_M_int.size() - 1);
2572       _M_m.reserve(_M_int.size() - 1);
2573       for (size_t __k = 0; __k < _M_int.size() - 1; ++__k)
2574 	{
2575 	  const _RealType __delta = _M_int[__k + 1] - _M_int[__k];
2576 	  __sum += 0.5 * (_M_den[__k + 1] + _M_den[__k]) * __delta;
2577 	  _M_cp.push_back(__sum);
2578 	  _M_m.push_back((_M_den[__k + 1] - _M_den[__k]) / __delta);
2579 	}
2580 
2581       //  Now normalize the densities...
2582       __detail::__transform(_M_den.begin(), _M_den.end(), _M_den.begin(),
2583 			  std::bind2nd(std::divides<double>(), __sum));
2584       //  ... and partial sums...
2585       __detail::__transform(_M_cp.begin(), _M_cp.end(), _M_cp.begin(),
2586 			    std::bind2nd(std::divides<double>(), __sum));
2587       //  ... and slopes.
2588       __detail::__transform(_M_m.begin(), _M_m.end(), _M_m.begin(),
2589 			    std::bind2nd(std::divides<double>(), __sum));
2590       //  Make sure the last cumulative probablility is one.
2591       _M_cp[_M_cp.size() - 1] = 1.0;
2592      }
2593 
2594   template<typename _RealType>
2595     template<typename _InputIteratorB, typename _InputIteratorW>
2596       piecewise_linear_distribution<_RealType>::param_type::
2597       param_type(_InputIteratorB __bbegin,
2598 		 _InputIteratorB __bend,
2599 		 _InputIteratorW __wbegin)
2600       : _M_int(), _M_den(), _M_cp(), _M_m()
2601       {
2602 	for (; __bbegin != __bend; ++__bbegin, ++__wbegin)
2603 	  {
2604 	    _M_int.push_back(*__bbegin);
2605 	    _M_den.push_back(*__wbegin);
2606 	  }
2607 
2608 	_M_initialize();
2609       }
2610 
2611   template<typename _RealType>
2612     template<typename _Func>
2613       piecewise_linear_distribution<_RealType>::param_type::
2614       param_type(initializer_list<_RealType> __bl, _Func __fw)
2615       : _M_int(), _M_den(), _M_cp(), _M_m()
2616       {
2617 	_M_int.reserve(__bl.size());
2618 	_M_den.reserve(__bl.size());
2619 	for (auto __biter = __bl.begin(); __biter != __bl.end(); ++__biter)
2620 	  {
2621 	    _M_int.push_back(*__biter);
2622 	    _M_den.push_back(__fw(*__biter));
2623 	  }
2624 
2625 	_M_initialize();
2626       }
2627 
2628   template<typename _RealType>
2629     template<typename _Func>
2630       piecewise_linear_distribution<_RealType>::param_type::
2631       param_type(size_t __nw, _RealType __xmin, _RealType __xmax, _Func __fw)
2632       : _M_int(), _M_den(), _M_cp(), _M_m()
2633       {
2634 	const size_t __n = __nw == 0 ? 1 : __nw;
2635 	const _RealType __delta = (__xmax - __xmin) / __n;
2636 
2637 	_M_int.reserve(__n + 1);
2638 	_M_den.reserve(__n + 1);
2639 	for (size_t __k = 0; __k <= __nw; ++__k)
2640 	  {
2641 	    _M_int.push_back(__xmin + __k * __delta);
2642 	    _M_den.push_back(__fw(_M_int[__k] + __delta));
2643 	  }
2644 
2645 	_M_initialize();
2646       }
2647 
2648   template<typename _RealType>
2649     template<typename _UniformRandomNumberGenerator>
2650       typename piecewise_linear_distribution<_RealType>::result_type
2651       piecewise_linear_distribution<_RealType>::
2652       operator()(_UniformRandomNumberGenerator& __urng,
2653 		 const param_type& __param)
2654       {
2655 	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
2656 	  __aurng(__urng);
2657 
2658 	const double __p = __aurng();
2659 	if (__param._M_cp.empty())
2660 	  return __p;
2661 
2662 	auto __pos = std::lower_bound(__param._M_cp.begin(),
2663 				      __param._M_cp.end(), __p);
2664 	const size_t __i = __pos - __param._M_cp.begin();
2665 
2666 	const double __pref = __i > 0 ? __param._M_cp[__i - 1] : 0.0;
2667 
2668 	const double __a = 0.5 * __param._M_m[__i];
2669 	const double __b = __param._M_den[__i];
2670 	const double __cm = __p - __pref;
2671 
2672 	_RealType __x = __param._M_int[__i];
2673 	if (__a == 0)
2674 	  __x += __cm / __b;
2675 	else
2676 	  {
2677 	    const double __d = __b * __b + 4.0 * __a * __cm;
2678 	    __x += 0.5 * (std::sqrt(__d) - __b) / __a;
2679           }
2680 
2681         return __x;
2682       }
2683 
2684   template<typename _RealType, typename _CharT, typename _Traits>
2685     std::basic_ostream<_CharT, _Traits>&
2686     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
2687 	       const piecewise_linear_distribution<_RealType>& __x)
2688     {
2689       typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
2690       typedef typename __ostream_type::ios_base    __ios_base;
2691 
2692       const typename __ios_base::fmtflags __flags = __os.flags();
2693       const _CharT __fill = __os.fill();
2694       const std::streamsize __precision = __os.precision();
2695       const _CharT __space = __os.widen(' ');
2696       __os.flags(__ios_base::scientific | __ios_base::left);
2697       __os.fill(__space);
2698       __os.precision(std::numeric_limits<_RealType>::max_digits10);
2699 
2700       std::vector<_RealType> __int = __x.intervals();
2701       __os << __int.size() - 1;
2702 
2703       for (auto __xit = __int.begin(); __xit != __int.end(); ++__xit)
2704 	__os << __space << *__xit;
2705 
2706       std::vector<double> __den = __x.densities();
2707       for (auto __dit = __den.begin(); __dit != __den.end(); ++__dit)
2708 	__os << __space << *__dit;
2709 
2710       __os.flags(__flags);
2711       __os.fill(__fill);
2712       __os.precision(__precision);
2713       return __os;
2714     }
2715 
2716   template<typename _RealType, typename _CharT, typename _Traits>
2717     std::basic_istream<_CharT, _Traits>&
2718     operator>>(std::basic_istream<_CharT, _Traits>& __is,
2719 	       piecewise_linear_distribution<_RealType>& __x)
2720     {
2721       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
2722       typedef typename __istream_type::ios_base    __ios_base;
2723 
2724       const typename __ios_base::fmtflags __flags = __is.flags();
2725       __is.flags(__ios_base::dec | __ios_base::skipws);
2726 
2727       size_t __n;
2728       __is >> __n;
2729 
2730       std::vector<_RealType> __int_vec;
2731       __int_vec.reserve(__n + 1);
2732       for (size_t __i = 0; __i <= __n; ++__i)
2733 	{
2734 	  _RealType __int;
2735 	  __is >> __int;
2736 	  __int_vec.push_back(__int);
2737 	}
2738 
2739       std::vector<double> __den_vec;
2740       __den_vec.reserve(__n + 1);
2741       for (size_t __i = 0; __i <= __n; ++__i)
2742 	{
2743 	  double __den;
2744 	  __is >> __den;
2745 	  __den_vec.push_back(__den);
2746 	}
2747 
2748       __x.param(typename piecewise_linear_distribution<_RealType>::
2749 	  param_type(__int_vec.begin(), __int_vec.end(), __den_vec.begin()));
2750 
2751       __is.flags(__flags);
2752       return __is;
2753     }
2754 
2755 
2756   template<typename _IntType>
2757     seed_seq::seed_seq(std::initializer_list<_IntType> __il)
2758     {
2759       for (auto __iter = __il.begin(); __iter != __il.end(); ++__iter)
2760 	_M_v.push_back(__detail::__mod<result_type,
2761 		       __detail::_Shift<result_type, 32>::__value>(*__iter));
2762     }
2763 
2764   template<typename _InputIterator>
2765     seed_seq::seed_seq(_InputIterator __begin, _InputIterator __end)
2766     {
2767       for (_InputIterator __iter = __begin; __iter != __end; ++__iter)
2768 	_M_v.push_back(__detail::__mod<result_type,
2769 		       __detail::_Shift<result_type, 32>::__value>(*__iter));
2770     }
2771 
2772   template<typename _RandomAccessIterator>
2773     void
2774     seed_seq::generate(_RandomAccessIterator __begin,
2775 		       _RandomAccessIterator __end)
2776     {
2777       typedef typename iterator_traits<_RandomAccessIterator>::value_type
2778         _Type;
2779 
2780       if (__begin == __end)
2781 	return;
2782 
2783       std::fill(__begin, __end, _Type(0x8b8b8b8bu));
2784 
2785       const size_t __n = __end - __begin;
2786       const size_t __s = _M_v.size();
2787       const size_t __t = (__n >= 623) ? 11
2788 		       : (__n >=  68) ? 7
2789 		       : (__n >=  39) ? 5
2790 		       : (__n >=   7) ? 3
2791 		       : (__n - 1) / 2;
2792       const size_t __p = (__n - __t) / 2;
2793       const size_t __q = __p + __t;
2794       const size_t __m = std::max(size_t(__s + 1), __n);
2795 
2796       for (size_t __k = 0; __k < __m; ++__k)
2797 	{
2798 	  _Type __arg = (__begin[__k % __n]
2799 			 ^ __begin[(__k + __p) % __n]
2800 			 ^ __begin[(__k - 1) % __n]);
2801 	  _Type __r1 = __arg ^ (__arg >> 27);
2802 	  __r1 = __detail::__mod<_Type,
2803 		    __detail::_Shift<_Type, 32>::__value>(1664525u * __r1);
2804 	  _Type __r2 = __r1;
2805 	  if (__k == 0)
2806 	    __r2 += __s;
2807 	  else if (__k <= __s)
2808 	    __r2 += __k % __n + _M_v[__k - 1];
2809 	  else
2810 	    __r2 += __k % __n;
2811 	  __r2 = __detail::__mod<_Type,
2812 	           __detail::_Shift<_Type, 32>::__value>(__r2);
2813 	  __begin[(__k + __p) % __n] += __r1;
2814 	  __begin[(__k + __q) % __n] += __r2;
2815 	  __begin[__k % __n] = __r2;
2816 	}
2817 
2818       for (size_t __k = __m; __k < __m + __n; ++__k)
2819 	{
2820 	  _Type __arg = (__begin[__k % __n]
2821 			 + __begin[(__k + __p) % __n]
2822 			 + __begin[(__k - 1) % __n]);
2823 	  _Type __r3 = __arg ^ (__arg >> 27);
2824 	  __r3 = __detail::__mod<_Type,
2825 		   __detail::_Shift<_Type, 32>::__value>(1566083941u * __r3);
2826 	  _Type __r4 = __r3 - __k % __n;
2827 	  __r4 = __detail::__mod<_Type,
2828 	           __detail::_Shift<_Type, 32>::__value>(__r4);
2829 	  __begin[(__k + __p) % __n] ^= __r3;
2830 	  __begin[(__k + __q) % __n] ^= __r4;
2831 	  __begin[__k % __n] = __r4;
2832 	}
2833     }
2834 
2835   template<typename _RealType, size_t __bits,
2836 	   typename _UniformRandomNumberGenerator>
2837     _RealType
2838     generate_canonical(_UniformRandomNumberGenerator& __urng)
2839     {
2840       const size_t __b
2841 	= std::min(static_cast<size_t>(std::numeric_limits<_RealType>::digits),
2842                    __bits);
2843       const long double __r = static_cast<long double>(__urng.max())
2844 			    - static_cast<long double>(__urng.min()) + 1.0L;
2845       const size_t __log2r = std::log(__r) / std::log(2.0L);
2846       size_t __k = std::max<size_t>(1UL, (__b + __log2r - 1UL) / __log2r);
2847       _RealType __sum = _RealType(0);
2848       _RealType __tmp = _RealType(1);
2849       for (; __k != 0; --__k)
2850 	{
2851 	  __sum += _RealType(__urng() - __urng.min()) * __tmp;
2852 	  __tmp *= __r;
2853 	}
2854       return __sum / __tmp;
2855     }
2856 
2857 _GLIBCXX_END_NAMESPACE_VERSION
2858 } // namespace
2859 
2860 #endif
2861