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1 | // random number generation -*- C++ -*- |
2 | ||
3 | // Copyright (C) 2006 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 2, 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 | // You should have received a copy of the GNU General Public License along | |
17 | // with this library; see the file COPYING. If not, write to the Free | |
18 | // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, | |
19 | // USA. | |
20 | ||
21 | // As a special exception, you may use this file as part of a free software | |
22 | // library without restriction. Specifically, if other files instantiate | |
23 | // templates or use macros or inline functions from this file, or you compile | |
24 | // this file and link it with other files to produce an executable, this | |
25 | // file does not by itself cause the resulting executable to be covered by | |
26 | // the GNU General Public License. This exception does not however | |
27 | // invalidate any other reasons why the executable file might be covered by | |
28 | // the GNU General Public License. | |
29 | ||
30 | #ifndef _STD_TR1_RANDOM | |
31 | #define _STD_TR1_RANDOM 1 | |
32 | ||
33 | /** | |
34 | * @file | |
35 | * This is a TR1 C++ Library header. | |
36 | */ | |
37 | ||
38 | #include <algorithm> | |
39 | #include <bits/concept_check.h> | |
40 | #include <bits/cpp_type_traits.h> | |
41 | #include <cmath> | |
42 | #include <debug/debug.h> | |
43 | #include <iterator> | |
44 | #include <iosfwd> | |
45 | #include <limits> | |
46 | #include <tr1/type_traits> | |
d8bc9819 | 47 | #include <fstream> |
86ad0dd6 PC |
48 | |
49 | namespace std | |
50 | { | |
51 | _GLIBCXX_BEGIN_NAMESPACE(tr1) | |
52 | ||
53 | // [5.1] Random number generation | |
54 | ||
55 | /** | |
56 | * @addtogroup tr1_random Random Number Generation | |
57 | * A facility for generating random numbers on selected distributions. | |
58 | * @{ | |
59 | */ | |
60 | ||
61 | /* | |
62 | * Implementation-space details. | |
63 | */ | |
64 | namespace _Private | |
65 | { | |
281864aa | 66 | // Type selectors -- are these already implemented elsewhere? |
86ad0dd6 PC |
67 | template<bool, typename _TpTrue, typename _TpFalse> |
68 | struct _Select | |
69 | { | |
281864aa | 70 | typedef _TpTrue _Type; |
86ad0dd6 PC |
71 | }; |
72 | ||
73 | template<typename _TpTrue, typename _TpFalse> | |
74 | struct _Select<false, _TpTrue, _TpFalse> | |
75 | { | |
281864aa | 76 | typedef _TpFalse _Type; |
86ad0dd6 PC |
77 | }; |
78 | ||
79 | /* | |
80 | * An adaptor class for converting the output of any Generator into | |
81 | * the input for a specific Distribution. | |
82 | */ | |
83 | template<typename _Generator, typename _Distribution> | |
84 | struct _Adaptor | |
85 | { | |
86 | typedef typename _Generator::result_type generated_type; | |
87 | typedef typename _Distribution::input_type result_type; | |
88 | ||
89 | public: | |
90 | _Adaptor(const _Generator& __g) | |
91 | : _M_g(__g) { } | |
92 | ||
93 | result_type | |
94 | operator()(); | |
95 | ||
96 | private: | |
97 | _Generator _M_g; | |
98 | }; | |
99 | ||
100 | /* | |
281864aa | 101 | * Converts a value generated by the adapted random number generator into a |
86ad0dd6 PC |
102 | * value in the input domain for the dependent random number distribution. |
103 | * | |
104 | * Because the type traits are compile time constants only the appropriate | |
105 | * clause of the if statements will actually be emitted by the compiler. | |
106 | */ | |
107 | template<typename _Generator, typename _Distribution> | |
108 | typename _Adaptor<_Generator, _Distribution>::result_type | |
109 | _Adaptor<_Generator, _Distribution>:: | |
110 | operator()() | |
111 | { | |
112 | result_type __return_value = 0; | |
113 | if (is_integral<generated_type>::value | |
114 | && is_integral<result_type>::value) | |
115 | __return_value = _M_g(); | |
116 | else if (is_integral<generated_type>::value | |
117 | && !is_integral<result_type>::value) | |
118 | __return_value = result_type(_M_g()) | |
119 | / result_type(_M_g.max() - _M_g.min() + 1); | |
120 | else if (!is_integral<generated_type>::value | |
121 | && !is_integral<result_type>::value) | |
122 | __return_value = result_type(_M_g()) | |
123 | / result_type(_M_g.max() - _M_g.min()); | |
124 | return __return_value; | |
125 | } | |
126 | ||
127 | } // namespace std::tr1::_Private | |
128 | ||
129 | ||
130 | /** | |
131 | * Produces random numbers on a given disribution function using a un uniform | |
132 | * random number generation engine. | |
133 | * | |
134 | * @todo the engine_value_type needs to be studied more carefully. | |
135 | */ | |
136 | template<typename _Generator, typename _Dist> | |
137 | class variate_generator | |
138 | { | |
139 | // Concept requirements. | |
140 | __glibcxx_class_requires(_Generator, _CopyConstructibleConcept) | |
141 | // __glibcxx_class_requires(_Generator, _GeneratorConcept) | |
142 | // __glibcxx_class_requires(_Dist, _GeneratorConcept) | |
143 | ||
144 | public: | |
145 | typedef _Generator engine_type; | |
146 | typedef _Private::_Adaptor<_Generator, _Dist> engine_value_type; | |
147 | typedef _Dist distribution_type; | |
148 | typedef typename _Dist::result_type result_type; | |
149 | ||
150 | // tr1:5.1.1 table 5.1 requirement | |
151 | typedef typename std::__enable_if<result_type, | |
152 | is_arithmetic<result_type>::value | |
153 | >::__type _IsValidType; | |
154 | ||
155 | public: | |
156 | /** | |
157 | * Constructs a variate generator with the uniform random number | |
281864aa | 158 | * generator @p __eng for the random distribution @p __dist. |
86ad0dd6 | 159 | * |
281864aa PC |
160 | * @throws Any exceptions which may thrown by the copy constructors of |
161 | * the @p _Generator or @p _Dist objects. | |
86ad0dd6 PC |
162 | */ |
163 | variate_generator(engine_type __eng, distribution_type __dist) | |
164 | : _M_engine(__eng), _M_dist(__dist) { } | |
165 | ||
166 | /** | |
167 | * Gets the next generated value on the distribution. | |
168 | */ | |
169 | result_type | |
170 | operator()(); | |
171 | ||
172 | template<typename _Tp> | |
173 | result_type | |
174 | operator()(_Tp __value); | |
175 | ||
176 | /** | |
177 | * Gets a reference to the underlying uniform random number generator | |
178 | * object. | |
179 | */ | |
180 | engine_value_type& | |
181 | engine() | |
182 | { return _M_engine; } | |
183 | ||
184 | /** | |
185 | * Gets a const reference to the underlying uniform random number | |
186 | * generator object. | |
187 | */ | |
188 | const engine_value_type& | |
189 | engine() const | |
190 | { return _M_engine; } | |
191 | ||
192 | /** | |
193 | * Gets a reference to the underlying random distribution. | |
194 | */ | |
195 | distribution_type& | |
196 | distribution() | |
197 | { return _M_dist; } | |
198 | ||
199 | /** | |
200 | * Gets a const reference to the underlying random distribution. | |
201 | */ | |
202 | const distribution_type& | |
203 | distribution() const | |
204 | { return _M_dist; } | |
205 | ||
206 | /** | |
207 | * Gets the closed lower bound of the distribution interval. | |
208 | */ | |
209 | result_type | |
210 | min() const | |
211 | { return this->distribution().min(); } | |
212 | ||
213 | /** | |
214 | * Gets the closed upper bound of the distribution interval. | |
215 | */ | |
216 | result_type | |
217 | max() const | |
218 | { return this->distribution().max(); } | |
219 | ||
220 | private: | |
221 | engine_value_type _M_engine; | |
222 | distribution_type _M_dist; | |
223 | }; | |
224 | ||
225 | /** | |
226 | * Gets the next random value on the given distribution. | |
227 | */ | |
228 | template<typename _Generator, typename _Dist> | |
229 | typename variate_generator<_Generator, _Dist>::result_type | |
230 | variate_generator<_Generator, _Dist>:: | |
231 | operator()() | |
232 | { return _M_dist(_M_engine); } | |
233 | ||
234 | /** | |
235 | * WTF? | |
236 | */ | |
237 | template<typename _Generator, typename _Dist> | |
238 | template<typename _Tp> | |
239 | typename variate_generator<_Generator, _Dist>::result_type | |
240 | variate_generator<_Generator, _Dist>:: | |
241 | operator()(_Tp __value) | |
242 | { return _M_dist(_M_engine, __value); } | |
243 | ||
244 | ||
245 | /** | |
246 | * @addtogroup tr1_random_generators Random Number Generators | |
247 | * @ingroup tr1_random | |
248 | * | |
249 | * These classes define objects which provide random or pseudorandom numbers, | |
250 | * either from a discrete or a continuous interval. The random number | |
251 | * generator supplied as a part of this library are all uniform random number | |
252 | * generators which provide a sequence of random number uniformly distributed | |
253 | * over their range. | |
254 | * | |
255 | * A number generator is a function object with an operator() that takes zero | |
256 | * arguments and returns a number. | |
257 | * | |
258 | * A compliant random number generator must satisy the following requirements. | |
259 | * <table border=1 cellpadding=10 cellspacing=0> | |
260 | * <caption align=top>Random Number Generator Requirements</caption> | |
261 | * <tr><td>To be documented.</td></tr> | |
262 | * </table> | |
263 | * | |
264 | * @{ | |
265 | */ | |
266 | ||
267 | /** | |
268 | * @brief A model of a linear congruential random number generator. | |
269 | * | |
270 | * A random number generator that produces pseudorandom numbers using the | |
271 | * linear function @f$x_{i+1}\leftarrow(ax_{i} + c) \bmod m @f$. | |
272 | * | |
281864aa PC |
273 | * The template parameter @p _UIntType must be an unsigned integral type |
274 | * large enough to store values up to (__m-1). If the template parameter | |
275 | * @p __m is 0, the modulus @p __m used is | |
276 | * std::numeric_limits<_UIntType>::max() plus 1. Otherwise, the template | |
277 | * parameters @p __a and @p __c must be less than @p __m. | |
86ad0dd6 PC |
278 | * |
279 | * The size of the state is @f$ 1 @f$. | |
280 | */ | |
281864aa | 281 | template<class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
86ad0dd6 PC |
282 | class linear_congruential |
283 | { | |
281864aa PC |
284 | __glibcxx_class_requires(_UIntType, _UnsignedIntegerConcept) |
285 | // __glibcpp_class_requires(__a < __m && __c < __m) | |
86ad0dd6 PC |
286 | |
287 | public: | |
288 | /** The type of the generated random value. */ | |
281864aa | 289 | typedef _UIntType result_type; |
86ad0dd6 PC |
290 | |
291 | /** The multiplier. */ | |
281864aa | 292 | static const _UIntType multiplier = __a; |
86ad0dd6 | 293 | /** An increment. */ |
281864aa | 294 | static const _UIntType increment = __c; |
86ad0dd6 | 295 | /** The modulus. */ |
281864aa | 296 | static const _UIntType modulus = __m; |
86ad0dd6 PC |
297 | |
298 | /** | |
299 | * Constructs a %linear_congruential random number generator engine with | |
281864aa | 300 | * seed @p __s. The default seed value is 1. |
86ad0dd6 | 301 | * |
281864aa | 302 | * @param __s The initial seed value. |
86ad0dd6 | 303 | */ |
281864aa | 304 | explicit linear_congruential(unsigned long __s = 1); |
86ad0dd6 PC |
305 | |
306 | /** | |
307 | * Constructs a %linear_congruential random number generator engine | |
281864aa | 308 | * seeded from the generator function @p __g. |
86ad0dd6 | 309 | * |
281864aa | 310 | * @param __g The seed generator function. |
86ad0dd6 | 311 | */ |
281864aa PC |
312 | template<class _Gen> |
313 | linear_congruential(_Gen& __g); | |
86ad0dd6 PC |
314 | |
315 | /** | |
281864aa PC |
316 | * Reseeds the %linear_congruential random number generator engine |
317 | * sequence to the seed @g __s. | |
86ad0dd6 | 318 | * |
281864aa | 319 | * @param __s The new seed. |
86ad0dd6 PC |
320 | */ |
321 | void | |
281864aa | 322 | seed(unsigned long __s = 1); |
86ad0dd6 PC |
323 | |
324 | /** | |
281864aa PC |
325 | * Reseeds the %linear_congruential random number generator engine |
326 | * sequence using values from the generator function @p __g. | |
86ad0dd6 | 327 | * |
281864aa | 328 | * @param __g the seed generator function. |
86ad0dd6 | 329 | */ |
281864aa | 330 | template<class _Gen> |
86ad0dd6 | 331 | void |
281864aa PC |
332 | seed(_Gen& __g) |
333 | { seed(__g, typename is_fundamental<_Gen>::type()); } | |
86ad0dd6 PC |
334 | |
335 | /** | |
336 | * Gets the smallest possible value in the output range. | |
337 | */ | |
338 | result_type | |
339 | min() const; | |
340 | ||
341 | /** | |
342 | * Gets the largest possible value in the output range. | |
343 | */ | |
344 | result_type | |
345 | max() const; | |
346 | ||
347 | /** | |
348 | * Gets the next random number in the sequence. | |
349 | */ | |
350 | result_type | |
351 | operator()(); | |
352 | ||
353 | /** | |
354 | * Compares two linear congruential random number generator objects of the | |
355 | * same type for equality. | |
356 | * | |
281864aa PC |
357 | * @param __lhs A linear congruential random number generator object. |
358 | * @param __rhs Another linear congruential random number generator obj. | |
86ad0dd6 PC |
359 | * |
360 | * @returns true if the two objects are equal, false otherwise. | |
361 | */ | |
362 | friend bool | |
281864aa PC |
363 | operator==(const linear_congruential& __lhs, |
364 | const linear_congruential& __rhs) | |
365 | { return __lhs._M_x == __rhs._M_x; } | |
86ad0dd6 PC |
366 | |
367 | /** | |
368 | * Compares two linear congruential random number generator objects of the | |
369 | * same type for inequality. | |
370 | * | |
281864aa PC |
371 | * @param __lhs A linear congruential random number generator object. |
372 | * @param __rhs Another linear congruential random number generator obj. | |
86ad0dd6 PC |
373 | * |
374 | * @returns true if the two objects are not equal, false otherwise. | |
375 | */ | |
376 | friend bool | |
281864aa PC |
377 | operator!=(const linear_congruential& __lhs, |
378 | const linear_congruential& __rhs) | |
379 | { return !(__lhs == __rhs); } | |
86ad0dd6 PC |
380 | |
381 | /** | |
281864aa | 382 | * Writes the textual representation of the state x(i) of x to @p __os. |
86ad0dd6 | 383 | * |
281864aa PC |
384 | * @param __os The output stream. |
385 | * @param __lcr A linear_congruential random number generator. | |
386 | * @returns __os. | |
86ad0dd6 | 387 | */ |
281864aa PC |
388 | template<typename _CharT, typename _Traits> |
389 | friend std::basic_ostream<_CharT, _Traits>& | |
390 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
391 | const linear_congruential& __lcr) | |
392 | { return __os << __lcr._M_x; } | |
86ad0dd6 PC |
393 | |
394 | /** | |
395 | * Sets the state of the engine by reading its textual | |
281864aa | 396 | * representation from @p __is. |
86ad0dd6 PC |
397 | * |
398 | * The textual representation must have been previously written using an | |
399 | * output stream whose imbued locale and whose type's template | |
281864aa PC |
400 | * specialization arguments _CharT and _Traits were the same as those of |
401 | * @p __is. | |
86ad0dd6 | 402 | * |
281864aa PC |
403 | * @param __is The input stream. |
404 | * @param __lcr A linear_congruential random number generator. | |
405 | * @returns __is. | |
86ad0dd6 | 406 | */ |
281864aa PC |
407 | template<typename _CharT, typename _Traits> |
408 | friend std::basic_istream<_CharT, _Traits>& | |
409 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
410 | linear_congruential& __lcr) | |
411 | { return __is >> __lcr._M_x; } | |
86ad0dd6 PC |
412 | |
413 | private: | |
281864aa | 414 | template<class _Gen> |
86ad0dd6 | 415 | void |
281864aa PC |
416 | seed(_Gen& __g, true_type) |
417 | { return seed(static_cast<unsigned long>(__g)); } | |
86ad0dd6 | 418 | |
281864aa | 419 | template<class _Gen> |
86ad0dd6 | 420 | void |
281864aa | 421 | seed(_Gen& __g, false_type); |
86ad0dd6 PC |
422 | |
423 | private: | |
281864aa | 424 | _UIntType _M_x; |
86ad0dd6 PC |
425 | }; |
426 | ||
427 | /** | |
428 | * The classic Minimum Standard rand0 of Lewis, Goodman, and Miller. | |
429 | */ | |
430 | typedef linear_congruential<unsigned int, 16807, 0, 2147483647> minstd_rand0; | |
431 | ||
432 | /** | |
433 | * An alternative LCR (Lehmer Generator function) . | |
434 | */ | |
435 | typedef linear_congruential<unsigned int, 48271, 0, 2147483647> minstd_rand; | |
436 | ||
437 | ||
438 | /** | |
439 | * A generalized feedback shift register discrete random number generator. | |
440 | * | |
441 | * This algorithm avoind multiplication and division and is designed to be | |
442 | * friendly to a pipelined architecture. If the parameters are chosen | |
443 | * correctly, this generator will produce numbers with a very long period and | |
444 | * fairly good apparent entropy, although still not cryptographically strong. | |
445 | * | |
446 | * The best way to use this generator is with the predefined mt19937 class. | |
447 | * | |
448 | * This algorithm was originally invented by Makoto Matsumoto and | |
449 | * Takuji Nishimura. | |
450 | * | |
451 | * @var word_size The number of bits in each element of the state vector. | |
452 | * @var state_size The degree of recursion. | |
453 | * @var shift_size The period parameter. | |
454 | * @var mask_bits The separation point bit index. | |
455 | * @var parameter_a The last row of the twist matrix. | |
456 | * @var output_u The first right-shift tempering matrix parameter. | |
457 | * @var output_s The first left-shift tempering matrix parameter. | |
458 | * @var output_b The first left-shift tempering matrix mask. | |
459 | * @var output_t The second left-shift tempering matrix parameter. | |
460 | * @var output_c The second left-shift tempering matrix mask. | |
461 | * @var output_l The second right-shift tempering matrix parameter. | |
462 | */ | |
281864aa PC |
463 | template<class _UIntType, int __w, int __n, int __m, int __r, |
464 | _UIntType __a, int __u, int __s, _UIntType __b, int __t, | |
465 | _UIntType __c, int __l> | |
86ad0dd6 PC |
466 | class mersenne_twister |
467 | { | |
281864aa | 468 | __glibcxx_class_requires(_UIntType, _UnsignedIntegerConcept) |
86ad0dd6 PC |
469 | |
470 | public: | |
471 | // types | |
281864aa | 472 | typedef _UIntType result_type ; |
86ad0dd6 PC |
473 | |
474 | // parameter values | |
281864aa PC |
475 | static const int word_size = __w; |
476 | static const int state_size = __n; | |
477 | static const int shift_size = __m; | |
478 | static const int mask_bits = __r; | |
479 | static const _UIntType parameter_a = __a; | |
480 | static const int output_u = __u; | |
481 | static const int output_s = __s; | |
482 | static const _UIntType output_b = __b; | |
483 | static const int output_t = __t; | |
484 | static const _UIntType output_c = __c; | |
485 | static const int output_l = __l; | |
86ad0dd6 PC |
486 | |
487 | // constructors and member function | |
488 | mersenne_twister() | |
489 | { seed(); } | |
490 | ||
491 | explicit | |
281864aa PC |
492 | mersenne_twister(unsigned long __value) |
493 | { seed(__value); } | |
86ad0dd6 | 494 | |
281864aa PC |
495 | template<class _Gen> |
496 | mersenne_twister(_Gen& __g) | |
497 | { seed(__g); } | |
86ad0dd6 PC |
498 | |
499 | void | |
500 | seed() | |
36ac3ed6 | 501 | { seed(5489UL); } |
86ad0dd6 PC |
502 | |
503 | void | |
281864aa | 504 | seed(unsigned long __value); |
86ad0dd6 | 505 | |
281864aa | 506 | template<class _Gen> |
86ad0dd6 | 507 | void |
281864aa PC |
508 | seed(_Gen& __g) |
509 | { seed(__g, typename is_fundamental<_Gen>::type()); } | |
86ad0dd6 PC |
510 | |
511 | result_type | |
512 | min() const | |
513 | { return 0; }; | |
514 | ||
515 | result_type | |
516 | max() const; | |
517 | ||
518 | result_type | |
519 | operator()(); | |
520 | ||
d95c1c48 PC |
521 | /** |
522 | * Compares two % mersenne_twister random number generator objects of | |
523 | * the same type for equality. | |
524 | * | |
525 | * @param __lhs A % mersenne_twister random number generator object. | |
526 | * @param __rhs Another % mersenne_twister random number generator | |
527 | * object. | |
528 | * | |
529 | * @returns true if the two objects are equal, false otherwise. | |
530 | */ | |
531 | friend bool | |
532 | operator==(const mersenne_twister& __lhs, | |
533 | const mersenne_twister& __rhs) | |
534 | { return std::equal(__lhs._M_x, __lhs._M_x + state_size, __rhs._M_x); } | |
535 | ||
536 | /** | |
537 | * Compares two % mersenne_twister random number generator objects of | |
538 | * the same type for inequality. | |
539 | * | |
540 | * @param __lhs A % mersenne_twister random number generator object. | |
541 | * @param __rhs Another % mersenne_twister random number generator | |
542 | * object. | |
543 | * | |
544 | * @returns true if the two objects are not equal, false otherwise. | |
545 | */ | |
546 | friend bool | |
547 | operator!=(const mersenne_twister& __lhs, | |
548 | const mersenne_twister& __rhs) | |
549 | { return !(__lhs == __rhs); } | |
550 | ||
551 | /** | |
552 | * Inserts the current state of a % mersenne_twister random number | |
553 | * generator engine @p __x into the output stream @p __os. | |
554 | * | |
555 | * @param __os An output stream. | |
556 | * @param __x A % mersenne_twister random number generator engine. | |
557 | * | |
558 | * @returns The output stream with the state of @p __x inserted or in | |
559 | * an error state. | |
560 | */ | |
561 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
562 | friend std::basic_ostream<_CharT, _Traits>& |
563 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
d95c1c48 PC |
564 | const mersenne_twister& __x) |
565 | { | |
566 | std::copy(__x._M_x, __x._M_x + state_size, | |
567 | std::ostream_iterator<_UIntType>(__os, " ")); | |
568 | return __os; | |
569 | } | |
570 | ||
571 | /** | |
572 | * Extracts the current state of a % mersenne_twister random number | |
573 | * generator engine @p __x from the input stream @p __is. | |
574 | * | |
575 | * @param __is An input stream. | |
576 | * @param __x A % mersenne_twister random number generator engine. | |
577 | * | |
578 | * @returns The input stream with the state of @p __x extracted or in | |
579 | * an error state. | |
580 | */ | |
581 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
582 | friend std::basic_istream<_CharT, _Traits>& |
583 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
d95c1c48 PC |
584 | mersenne_twister& __x) |
585 | { | |
586 | for (int __i = 0; __i < state_size; ++__i) | |
587 | __is >> __x._M_x[__i]; | |
588 | return __is; | |
589 | } | |
590 | ||
86ad0dd6 | 591 | private: |
281864aa | 592 | template<class _Gen> |
86ad0dd6 | 593 | void |
281864aa PC |
594 | seed(_Gen& __g, true_type) |
595 | { return seed(static_cast<unsigned long>(__g)); } | |
86ad0dd6 | 596 | |
281864aa | 597 | template<class _Gen> |
86ad0dd6 | 598 | void |
281864aa | 599 | seed(_Gen& __g, false_type); |
86ad0dd6 PC |
600 | |
601 | private: | |
281864aa PC |
602 | _UIntType _M_x[state_size]; |
603 | int _M_p; | |
86ad0dd6 PC |
604 | }; |
605 | ||
606 | /** | |
607 | * The classic Mersenne Twister. | |
608 | * | |
609 | * Reference: | |
610 | * M. Matsumoto and T. Nishimura, "Mersenne Twister: A 623-Dimensionally | |
611 | * Equidistributed Uniform Pseudo-Random Number Generator", ACM Transactions | |
612 | * on Modeling and Computer Simulation, Vol. 8, No. 1, January 1998, pp 3-30. | |
613 | */ | |
614 | typedef mersenne_twister< | |
615 | unsigned long, 32, 624, 397, 31, | |
616 | 0x9908b0dful, 11, 7, | |
617 | 0x9d2c5680ul, 15, | |
618 | 0xefc60000ul, 18 | |
619 | > mt19937; | |
620 | ||
621 | ||
622 | /** | |
623 | * @brief The Marsaglia-Zaman generator. | |
624 | * | |
625 | * This is a model of a Generalized Fibonacci discrete random number | |
626 | * generator, sometimes referred to as the SWC generator. | |
627 | * | |
628 | * A discrete random number generator that produces pseudorandom numbers using | |
629 | * @f$x_{i}\leftarrow(x_{i - s} - x_{i - r} - carry_{i-1}) \bmod m @f$. | |
630 | * | |
631 | * The size of the state is @f$ r @f$ | |
632 | * and the maximum period of the generator is @f$ m^r - m^s -1 @f$. | |
633 | * | |
634 | * N1688[4.13] says "the template parameter _IntType shall denote an integral | |
635 | * type large enough to store values up to m." | |
636 | * | |
637 | * @if maint | |
638 | * @var _M_x The state of te generator. This is a ring buffer. | |
639 | * @var _M_carry The carry. | |
640 | * @var _M_p Current index of x(i - r). | |
641 | * @endif | |
642 | */ | |
281864aa | 643 | template<typename _IntType, _IntType __m, int __s, int __r> |
86ad0dd6 PC |
644 | class subtract_with_carry |
645 | { | |
646 | __glibcxx_class_requires(_IntType, _IntegerConcept) | |
647 | ||
648 | public: | |
649 | /** The type of the generated random value. */ | |
650 | typedef _IntType result_type; | |
651 | ||
652 | // parameter values | |
281864aa PC |
653 | static const _IntType modulus = __m; |
654 | static const int long_lag = __r; | |
655 | static const int short_lag = __s; | |
86ad0dd6 PC |
656 | |
657 | public: | |
658 | /** | |
659 | * Constructs a default-initialized % subtract_with_carry random number | |
660 | * generator. | |
661 | */ | |
662 | subtract_with_carry() | |
663 | { this->seed(); } | |
664 | ||
665 | /** | |
666 | * Constructs an explicitly seeded % subtract_with_carry random number | |
667 | * generator. | |
668 | */ | |
669 | explicit | |
281864aa | 670 | subtract_with_carry(unsigned long __value) |
86ad0dd6 PC |
671 | { this->seed(__value); } |
672 | ||
673 | /** | |
674 | * Constructs a % subtract_with_carry random number generator seeded from | |
675 | * the PAD iterated by [__first, last). | |
676 | */ | |
281864aa PC |
677 | template<class _Gen> |
678 | subtract_with_carry(_Gen& __g) | |
679 | { this->seed(__g); } | |
86ad0dd6 PC |
680 | |
681 | /** | |
682 | * Seeds the initial state @f$ x_0 @f$ of the random number generator. | |
683 | * | |
684 | * @note This implementation follows the tr1 specification but will | |
685 | * obviously not work correctly on all platforms, since it has hardcoded | |
686 | * values that may overflow ints on some platforms. | |
687 | * | |
688 | * N1688[4.19] modifies this as follows. | |
689 | * If @p __value == 0, sets value to 19780503. In any case, with a linear | |
690 | * congruential generator lcg(i) having parameters @f$ m_{lcg} = | |
691 | * 2147483563, a_{lcg} = 40014, c_{lcg} = 0, and lcg(0) = value @f$, sets | |
692 | * @f$ x_{-r} \dots x_{-1} @f$ to | |
693 | * @f$ lcg(1) \bmod m \dots lcg(r) \bmod m @f$ respectively. | |
694 | * If @f$ x_{-1} = 0 @f$ set carry to 1, otherwise sets carry to 0. | |
695 | */ | |
696 | void | |
281864aa | 697 | seed(unsigned long __value = 19780503); |
86ad0dd6 PC |
698 | |
699 | /** | |
700 | * Seeds the initial state @f$ x_0 @f$ of the % subtract_with_carry | |
701 | * random number generator. | |
702 | */ | |
281864aa | 703 | template<class _Gen> |
86ad0dd6 | 704 | void |
281864aa PC |
705 | seed(_Gen& __g) |
706 | { seed(__g, typename is_fundamental<_Gen>::type()); } | |
86ad0dd6 PC |
707 | |
708 | /** | |
709 | * Gets the inclusive minimum value of the range of random integers | |
710 | * returned by this generator. | |
711 | */ | |
712 | result_type | |
713 | min() const | |
714 | { return 0; } | |
715 | ||
716 | /** | |
717 | * Gets the inclusive maximum value of the range of random integers | |
718 | * returned by this generator. | |
719 | */ | |
720 | result_type | |
721 | max() const | |
722 | { return this->modulus - 1; } | |
723 | ||
724 | /** | |
725 | * Gets the next random number in the sequence. | |
726 | */ | |
727 | result_type | |
728 | operator()(); | |
729 | ||
730 | /** | |
731 | * Compares two % subtract_with_carry random number generator objects of | |
732 | * the same type for equality. | |
733 | * | |
734 | * @param __lhs A % subtract_with_carry random number generator object. | |
735 | * @param __rhs Another % subtract_with_carry random number generator | |
736 | * object. | |
737 | * | |
738 | * @returns true if the two objects are equal, false otherwise. | |
739 | */ | |
740 | friend bool | |
741 | operator==(const subtract_with_carry& __lhs, | |
742 | const subtract_with_carry& __rhs) | |
d95c1c48 | 743 | { return std::equal(__lhs._M_x, __lhs._M_x + long_lag, __rhs._M_x); } |
86ad0dd6 PC |
744 | |
745 | /** | |
746 | * Compares two % subtract_with_carry random number generator objects of | |
747 | * the same type for inequality. | |
748 | * | |
749 | * @param __lhs A % subtract_with_carry random number generator object. | |
750 | * @param __rhs Another % subtract_with_carry random number generator | |
751 | * object. | |
752 | * | |
753 | * @returns true if the two objects are not equal, false otherwise. | |
754 | */ | |
755 | friend bool | |
756 | operator!=(const subtract_with_carry& __lhs, | |
757 | const subtract_with_carry& __rhs) | |
758 | { return !(__lhs == __rhs); } | |
759 | ||
760 | /** | |
761 | * Inserts the current state of a % subtract_with_carry random number | |
d95c1c48 | 762 | * generator engine @p __x into the output stream @p __os. |
86ad0dd6 PC |
763 | * |
764 | * @param __os An output stream. | |
765 | * @param __x A % subtract_with_carry random number generator engine. | |
766 | * | |
d95c1c48 PC |
767 | * @returns The output stream with the state of @p __x inserted or in |
768 | * an error state. | |
86ad0dd6 PC |
769 | */ |
770 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
771 | friend std::basic_ostream<_CharT, _Traits>& |
772 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 PC |
773 | const subtract_with_carry& __x) |
774 | { | |
d95c1c48 | 775 | std::copy(__x._M_x, __x._M_x + long_lag, |
86ad0dd6 PC |
776 | std::ostream_iterator<_IntType>(__os, " ")); |
777 | return __os << __x._M_carry; | |
778 | } | |
779 | ||
780 | /** | |
781 | * Extracts the current state of a % subtract_with_carry random number | |
d95c1c48 | 782 | * generator engine @p __x from the input stream @p __is. |
86ad0dd6 PC |
783 | * |
784 | * @param __is An input stream. | |
785 | * @param __x A % subtract_with_carry random number generator engine. | |
786 | * | |
d95c1c48 PC |
787 | * @returns The input stream with the state of @p __x extracted or in |
788 | * an error state. | |
86ad0dd6 PC |
789 | */ |
790 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
791 | friend std::basic_istream<_CharT, _Traits>& |
792 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
86ad0dd6 PC |
793 | subtract_with_carry& __x) |
794 | { | |
d95c1c48 | 795 | for (int __i = 0; __i < long_lag; ++__i) |
86ad0dd6 PC |
796 | __is >> __x._M_x[__i]; |
797 | __is >> __x._M_carry; | |
798 | return __is; | |
799 | } | |
800 | ||
801 | private: | |
281864aa | 802 | template<class _Gen> |
86ad0dd6 | 803 | void |
281864aa PC |
804 | seed(_Gen& __g, true_type) |
805 | { return seed(static_cast<unsigned long>(__g)); } | |
86ad0dd6 | 806 | |
281864aa | 807 | template<class _Gen> |
86ad0dd6 | 808 | void |
281864aa | 809 | seed(_Gen& __g, false_type); |
86ad0dd6 PC |
810 | |
811 | private: | |
812 | int _M_p; | |
813 | result_type _M_x[long_lag]; | |
814 | result_type _M_carry; | |
815 | }; | |
816 | ||
817 | ||
818 | /** | |
819 | * Produces random numbers from some base engine by discarding blocks of | |
820 | * data. | |
821 | * | |
281864aa | 822 | * 0 <= @p __r <= @p __p |
86ad0dd6 | 823 | */ |
281864aa | 824 | template<class _UniformRandomNumberGenerator, int __p, int __r> |
86ad0dd6 PC |
825 | class discard_block |
826 | { | |
827 | // __glibcxx_class_requires(typename base_type::result_type, | |
e4ec6e19 | 828 | // ArithmeticTypeConcept) |
86ad0dd6 PC |
829 | |
830 | public: | |
831 | /** The type of the underlying generator engine. */ | |
281864aa | 832 | typedef _UniformRandomNumberGenerator base_type; |
86ad0dd6 PC |
833 | /** The type of the generated random value. */ |
834 | typedef typename base_type::result_type result_type; | |
835 | ||
836 | // parameter values | |
281864aa PC |
837 | static const int block_size = __p; |
838 | static const int used_block = __r; | |
86ad0dd6 PC |
839 | |
840 | /** | |
841 | * Constructs a default %discard_block engine. | |
842 | * | |
843 | * The underlying engine is default constrcuted as well. | |
844 | */ | |
845 | discard_block() | |
846 | : _M_n(0) { } | |
847 | ||
848 | /** | |
849 | * Copy constructs a %discard_block engine. | |
850 | * | |
851 | * Copies an existing base class random number geenerator. | |
852 | * @param rng An existing (base class) engine object. | |
853 | */ | |
281864aa PC |
854 | explicit discard_block(const base_type& __rng) |
855 | : _M_b(__rng) , _M_n(0) { } | |
86ad0dd6 PC |
856 | |
857 | /** | |
858 | * Seed constructs a %discard_block engine. | |
859 | * | |
281864aa PC |
860 | * Constructs the underlying generator engine seeded with @p __s. |
861 | * @param __s A seed value for the base class engine. | |
86ad0dd6 | 862 | */ |
281864aa PC |
863 | explicit discard_block(unsigned long __s) |
864 | : _M_b(__s), _M_n(0) { } | |
86ad0dd6 PC |
865 | |
866 | /** | |
867 | * Generator constructs a %discard_block engine. | |
868 | * | |
281864aa | 869 | * @param __g A seed generator function. |
86ad0dd6 | 870 | */ |
281864aa PC |
871 | template<class _Gen> |
872 | discard_block(_Gen& __g) | |
873 | : _M_b(__g), _M_n(0) { } | |
86ad0dd6 PC |
874 | |
875 | /** | |
876 | * Reseeds the %discard_block object with the default seed for the | |
877 | * underlying base class generator engine. | |
878 | */ | |
879 | void seed() | |
880 | { | |
881 | _M_b.seed(); | |
882 | _M_n = 0; | |
883 | } | |
884 | ||
885 | /** | |
886 | * Reseeds the %discard_block object with the given seed generator | |
887 | * function. | |
281864aa | 888 | * @param __g A seed generator function. |
86ad0dd6 | 889 | */ |
281864aa PC |
890 | template<class _Gen> |
891 | void seed(_Gen& __g) | |
86ad0dd6 | 892 | { |
281864aa | 893 | _M_b.seed(__g); |
86ad0dd6 PC |
894 | _M_n = 0; |
895 | } | |
896 | ||
897 | /** | |
898 | * Gets a const reference to the underlying generator engine object. | |
899 | */ | |
900 | const base_type& | |
901 | base() const | |
902 | { return _M_b; } | |
903 | ||
904 | /** | |
905 | * Gets the minimum value in the generated random number range. | |
906 | */ | |
907 | result_type | |
908 | min() const | |
909 | { return _M_b.min(); } | |
910 | ||
911 | /** | |
912 | * Gets the maximum value in the generated random number range. | |
913 | */ | |
914 | result_type | |
915 | max() const | |
916 | { return _M_b.max(); } | |
917 | ||
918 | /** | |
919 | * Gets the next value in the generated random number sequence. | |
920 | */ | |
921 | result_type | |
922 | operator()(); | |
923 | ||
924 | /** | |
925 | * Compares two %discard_block random number generator objects of | |
926 | * the same type for equality. | |
927 | * | |
928 | * @param __lhs A %discard_block random number generator object. | |
929 | * @param __rhs Another %discard_block random number generator | |
930 | * object. | |
931 | * | |
932 | * @returns true if the two objects are equal, false otherwise. | |
933 | */ | |
934 | friend bool | |
935 | operator==(const discard_block& __lhs, const discard_block& __rhs) | |
d95c1c48 | 936 | { return (__lhs._M_b == __rhs._M_b) && (__lhs._M_n == __rhs._M_n); } |
86ad0dd6 PC |
937 | |
938 | /** | |
939 | * Compares two %discard_block random number generator objects of | |
940 | * the same type for inequality. | |
941 | * | |
942 | * @param __lhs A %discard_block random number generator object. | |
943 | * @param __rhs Another %discard_block random number generator | |
944 | * object. | |
945 | * | |
946 | * @returns true if the two objects are not equal, false otherwise. | |
947 | */ | |
948 | friend bool | |
949 | operator!=(const discard_block& __lhs, const discard_block& __rhs) | |
950 | { return !(__lhs == __rhs); } | |
951 | ||
952 | /** | |
953 | * Inserts the current state of a %discard_block random number | |
d95c1c48 | 954 | * generator engine @p __x into the output stream @p __os. |
86ad0dd6 PC |
955 | * |
956 | * @param __os An output stream. | |
957 | * @param __x A %discard_block random number generator engine. | |
958 | * | |
d95c1c48 PC |
959 | * @returns The output stream with the state of @p __x inserted or in |
960 | * an error state. | |
86ad0dd6 PC |
961 | */ |
962 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
963 | friend std::basic_ostream<_CharT, _Traits>& |
964 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 PC |
965 | const discard_block& __x) |
966 | { return __os << __x._M_b << " " << __x._M_n; } | |
967 | ||
968 | /** | |
969 | * Extracts the current state of a % subtract_with_carry random number | |
d95c1c48 | 970 | * generator engine @p __x from the input stream @p __is. |
86ad0dd6 PC |
971 | * |
972 | * @param __is An input stream. | |
973 | * @param __x A %discard_block random number generator engine. | |
974 | * | |
d95c1c48 PC |
975 | * @returns The input stream with the state of @p __x extracted or in |
976 | * an error state. | |
86ad0dd6 PC |
977 | */ |
978 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
979 | friend std::basic_istream<_CharT, _Traits>& |
980 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
86ad0dd6 PC |
981 | discard_block& __x) |
982 | { return __is >> __x._M_b >> __x._M_n; } | |
983 | ||
984 | private: | |
985 | base_type _M_b; | |
986 | int _M_n; | |
987 | }; | |
988 | ||
989 | ||
990 | /** | |
991 | * James's luxury-level-3 integer adaptation of Luescher's generator. | |
992 | */ | |
993 | typedef discard_block< | |
e4ec6e19 | 994 | subtract_with_carry<int, (1 << 24), 10, 24>, |
86ad0dd6 PC |
995 | 223, |
996 | 24 | |
997 | > ranlux3; | |
998 | ||
999 | /** | |
1000 | * James's luxury-level-4 integer adaptation of Luescher's generator. | |
1001 | */ | |
1002 | typedef discard_block< | |
e4ec6e19 | 1003 | subtract_with_carry<int, (1 << 24), 10, 24>, |
86ad0dd6 PC |
1004 | 389, |
1005 | 24 | |
1006 | > ranlux4; | |
1007 | ||
1008 | ||
1009 | /** | |
1010 | * A random number generator adaptor class that combines two random number | |
1011 | * generator engines into a single output sequence. | |
1012 | */ | |
281864aa PC |
1013 | template<class _UniformRandomNumberGenerator1, int __s1, |
1014 | class _UniformRandomNumberGenerator2, int __s2> | |
86ad0dd6 PC |
1015 | class xor_combine |
1016 | { | |
281864aa | 1017 | // __glibcxx_class_requires(typename _UniformRandomNumberGenerator1:: |
e4ec6e19 | 1018 | // result_type, ArithmeticTypeConcept) |
281864aa | 1019 | // __glibcxx_class_requires(typename _UniformRandomNumberGenerator2:: |
e4ec6e19 | 1020 | // result_type, ArithmeticTypeConcept) |
86ad0dd6 PC |
1021 | |
1022 | public: | |
1023 | /** The type of the the first underlying generator engine. */ | |
e4ec6e19 | 1024 | typedef _UniformRandomNumberGenerator1 base1_type; |
86ad0dd6 | 1025 | /** The type of the the second underlying generator engine. */ |
e4ec6e19 PC |
1026 | typedef _UniformRandomNumberGenerator2 base2_type; |
1027 | ||
1028 | private: | |
1029 | typedef typename base1_type::result_type _Result_type1; | |
1030 | typedef typename base2_type::result_type _Result_type2; | |
1031 | ||
1032 | public: | |
86ad0dd6 PC |
1033 | /** The type of the generated random value. */ |
1034 | typedef typename _Private::_Select< | |
e4ec6e19 PC |
1035 | (sizeof(_Result_type1) > sizeof(_Result_type2)), |
1036 | _Result_type1, _Result_type2>::_Type result_type; | |
86ad0dd6 PC |
1037 | |
1038 | // parameter values | |
281864aa PC |
1039 | static const int shift1 = __s1; |
1040 | static const int shift2 = __s2; | |
86ad0dd6 PC |
1041 | |
1042 | // constructors and member function | |
1043 | xor_combine() { } | |
1044 | ||
281864aa PC |
1045 | xor_combine(const base1_type& __rng1, const base2_type& __rng2) |
1046 | : _M_b1(__rng1), _M_b2(__rng2) { } | |
86ad0dd6 | 1047 | |
281864aa PC |
1048 | xor_combine(unsigned long __s) |
1049 | : _M_b1(__s), _M_b2(__s + 1) { } | |
86ad0dd6 | 1050 | |
281864aa PC |
1051 | template<class _Gen> |
1052 | xor_combine(_Gen& __g) | |
1053 | : _M_b1(__g), _M_b2(__g) { } | |
86ad0dd6 PC |
1054 | |
1055 | void | |
1056 | seed() | |
1057 | { | |
1058 | _M_b1.seed(); | |
1059 | _M_b2.seed(); | |
1060 | } | |
1061 | ||
281864aa | 1062 | template<class _Gen> |
86ad0dd6 | 1063 | void |
281864aa | 1064 | seed(_Gen& __g) |
86ad0dd6 | 1065 | { |
281864aa PC |
1066 | _M_b1.seed(__g); |
1067 | _M_b2.seed(__g); | |
86ad0dd6 PC |
1068 | } |
1069 | ||
1070 | const base1_type& | |
1071 | base1() const | |
1072 | { return _M_b1; } | |
1073 | ||
1074 | const base2_type& | |
1075 | base2() const | |
1076 | { return _M_b2; } | |
1077 | ||
1078 | result_type | |
1079 | min() const | |
1080 | { return _M_b1.min() ^ _M_b2.min(); } | |
1081 | ||
1082 | result_type | |
1083 | max() const | |
1084 | { return _M_b1.max() | _M_b2.max(); } | |
1085 | ||
1086 | /** | |
1087 | * Gets the next random number in the sequence. | |
1088 | */ | |
1089 | result_type | |
1090 | operator()() | |
1091 | { return ((_M_b1() << shift1) ^ (_M_b2() << shift2)); } | |
1092 | ||
1093 | /** | |
1094 | * Compares two %xor_combine random number generator objects of | |
1095 | * the same type for equality. | |
1096 | * | |
1097 | * @param __lhs A %xor_combine random number generator object. | |
1098 | * @param __rhs Another %xor_combine random number generator | |
1099 | * object. | |
1100 | * | |
1101 | * @returns true if the two objects are equal, false otherwise. | |
1102 | */ | |
1103 | friend bool | |
1104 | operator==(const xor_combine& __lhs, const xor_combine& __rhs) | |
1105 | { | |
1106 | return (__lhs.base1() == __rhs.base1()) | |
d95c1c48 | 1107 | && (__lhs.base2() == __rhs.base2()); |
86ad0dd6 PC |
1108 | } |
1109 | ||
1110 | /** | |
1111 | * Compares two %xor_combine random number generator objects of | |
1112 | * the same type for inequality. | |
1113 | * | |
1114 | * @param __lhs A %xor_combine random number generator object. | |
1115 | * @param __rhs Another %xor_combine random number generator | |
1116 | * object. | |
1117 | * | |
1118 | * @returns true if the two objects are not equal, false otherwise. | |
1119 | */ | |
1120 | friend bool | |
1121 | operator!=(const xor_combine& __lhs, const xor_combine& __rhs) | |
1122 | { return !(__lhs == __rhs); } | |
1123 | ||
1124 | /** | |
1125 | * Inserts the current state of a %xor_combine random number | |
d95c1c48 | 1126 | * generator engine @p __x into the output stream @p __os. |
86ad0dd6 PC |
1127 | * |
1128 | * @param __os An output stream. | |
1129 | * @param __x A %xor_combine random number generator engine. | |
1130 | * | |
d95c1c48 PC |
1131 | * @returns The output stream with the state of @p __x inserted or in |
1132 | * an error state. | |
86ad0dd6 PC |
1133 | */ |
1134 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1135 | friend std::basic_ostream<_CharT, _Traits>& |
1136 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 PC |
1137 | const xor_combine& __x) |
1138 | { return __os << __x.base1() << " " << __x.base1(); } | |
1139 | ||
1140 | /** | |
1141 | * Extracts the current state of a %xor_combine random number | |
d95c1c48 | 1142 | * generator engine @p __x from the input stream @p __is. |
86ad0dd6 PC |
1143 | * |
1144 | * @param __is An input stream. | |
1145 | * @param __x A %xor_combine random number generator engine. | |
1146 | * | |
d95c1c48 PC |
1147 | * @returns The input stream with the state of @p __x extracted or in |
1148 | * an error state. | |
86ad0dd6 PC |
1149 | */ |
1150 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1151 | friend std::basic_istream<_CharT, _Traits>& |
1152 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
86ad0dd6 PC |
1153 | xor_combine& __x) |
1154 | { return __is >> __x._M_b1 >> __x._M_b2; } | |
1155 | ||
1156 | private: | |
1157 | base1_type _M_b1; | |
1158 | base2_type _M_b2; | |
1159 | }; | |
1160 | ||
1161 | ||
1162 | /** | |
1163 | * A standard interface to a platform-specific non-deterministic random number | |
1164 | * generator (if any are available). | |
86ad0dd6 PC |
1165 | */ |
1166 | class random_device | |
1167 | { | |
1168 | public: | |
1169 | // types | |
1170 | typedef unsigned int result_type; | |
410fce92 | 1171 | |
86ad0dd6 | 1172 | // constructors, destructors and member functions |
d8bc9819 PC |
1173 | |
1174 | #ifdef _GLIBCXX_USE_RANDOM_TR1 | |
410fce92 | 1175 | |
d8bc9819 PC |
1176 | explicit |
1177 | random_device(const std::string& __token = "/dev/urandom") | |
1178 | { | |
1179 | if ((__token != "/dev/urandom" && __token != "/dev/random") | |
410fce92 PC |
1180 | || !_M_filebuf.open(__token.c_str(), |
1181 | std::ios_base::in | std::ios_base::binary)) | |
d8bc9819 PC |
1182 | std::__throw_runtime_error(__N("random_device::" |
1183 | "random_device(const std::string&)")); | |
1184 | } | |
1185 | ||
1186 | ~random_device() | |
1187 | { _M_filebuf.close(); } | |
1188 | ||
1189 | #else | |
410fce92 | 1190 | |
d8bc9819 | 1191 | explicit |
e4ec6e19 | 1192 | random_device(const std::string& __token = "mt19937") |
410fce92 PC |
1193 | : _M_mt(_M_strtoul(__token)) { } |
1194 | ||
1195 | private: | |
1196 | static unsigned long | |
1197 | _M_strtoul(const std::string& __str) | |
d8bc9819 | 1198 | { |
410fce92 | 1199 | unsigned long __ret = 5489UL; |
e4ec6e19 | 1200 | if (__str != "mt19937") |
d8bc9819 | 1201 | { |
410fce92 PC |
1202 | const char* __nptr = __str.c_str(); |
1203 | char* __endptr; | |
1204 | __ret = std::strtoul(__nptr, &__endptr, 0); | |
1205 | if (*__nptr == '\0' || *__endptr != '\0') | |
1206 | std::__throw_runtime_error(__N("random_device::_M_strtoul" | |
d8bc9819 | 1207 | "(const std::string&)")); |
d8bc9819 | 1208 | } |
410fce92 | 1209 | return __ret; |
d8bc9819 | 1210 | } |
410fce92 PC |
1211 | |
1212 | public: | |
1213 | ||
d8bc9819 PC |
1214 | #endif |
1215 | ||
1216 | result_type | |
1217 | min() const | |
1218 | { return std::numeric_limits<result_type>::min(); } | |
1219 | ||
1220 | result_type | |
1221 | max() const | |
1222 | { return std::numeric_limits<result_type>::max(); } | |
1223 | ||
1224 | double | |
1225 | entropy() const | |
1226 | { return 0.0; } | |
1227 | ||
1228 | result_type | |
1229 | operator()() | |
1230 | { | |
1231 | #ifdef _GLIBCXX_USE_RANDOM_TR1 | |
1232 | result_type __ret; | |
1233 | _M_filebuf.sgetn(reinterpret_cast<char*>(&__ret), sizeof(result_type)); | |
1234 | return __ret; | |
1235 | #else | |
410fce92 | 1236 | return _M_mt(); |
d8bc9819 PC |
1237 | #endif |
1238 | } | |
86ad0dd6 PC |
1239 | |
1240 | private: | |
281864aa PC |
1241 | random_device(const random_device&); |
1242 | void operator=(const random_device&); | |
d8bc9819 PC |
1243 | |
1244 | #ifdef _GLIBCXX_USE_RANDOM_TR1 | |
1245 | std::filebuf _M_filebuf; | |
410fce92 PC |
1246 | #else |
1247 | mt19937 _M_mt; | |
1248 | #endif | |
86ad0dd6 PC |
1249 | }; |
1250 | ||
1251 | /* @} */ // group tr1_random_generators | |
1252 | ||
1253 | /** | |
1254 | * @addtogroup tr1_random_distributions Random Number Distributions | |
1255 | * @ingroup tr1_random | |
1256 | * @{ | |
1257 | */ | |
1258 | ||
1259 | /** | |
1260 | * @addtogroup tr1_random_distributions_discrete Discrete Distributions | |
1261 | * @ingroup tr1_random_distributions | |
1262 | * @{ | |
1263 | */ | |
1264 | ||
1265 | /** | |
1266 | * @brief Uniform discrete distribution for random numbers. | |
1267 | * A discrete random distribution on the range @f$[min, max]@f$ with equal | |
1268 | * probability throughout the range. | |
1269 | */ | |
1270 | template<typename _IntType = int> | |
1271 | class uniform_int | |
1272 | { | |
1273 | __glibcxx_class_requires(_IntType, _IntegerConcept) | |
1274 | ||
1275 | public: | |
1276 | /** The type of the parameters of the distribution. */ | |
1277 | typedef _IntType input_type; | |
1278 | /** The type of the range of the distribution. */ | |
1279 | typedef _IntType result_type; | |
1280 | ||
1281 | public: | |
1282 | /** | |
1283 | * Constructs a uniform distribution object. | |
1284 | */ | |
1285 | explicit | |
1286 | uniform_int(_IntType __min = 0, _IntType __max = 9) | |
1287 | : _M_min(__min), _M_max(__max) | |
1288 | { | |
1289 | _GLIBCXX_DEBUG_ASSERT(_M_min <= _M_max); | |
1290 | } | |
1291 | ||
1292 | /** | |
1293 | * Gets the inclusive lower bound of the distribution range. | |
1294 | */ | |
1295 | result_type | |
1296 | min() const | |
1297 | { return _M_min; } | |
1298 | ||
1299 | /** | |
1300 | * Gets the inclusive upper bound of the distribution range. | |
1301 | */ | |
1302 | result_type | |
1303 | max() const | |
1304 | { return _M_max; } | |
1305 | ||
1306 | /** | |
1307 | * Resets the distribution state. | |
1308 | * | |
1309 | * Does nothing for the uniform integer distribution. | |
1310 | */ | |
1311 | void | |
1312 | reset() { } | |
1313 | ||
1314 | /** | |
1315 | * Gets a uniformly distributed random number in the range | |
1316 | * @f$(min, max)@f$. | |
1317 | */ | |
1318 | template<typename _UniformRandomNumberGenerator> | |
1319 | result_type | |
1320 | operator()(_UniformRandomNumberGenerator& __urng) | |
1321 | { return (__urng() % (_M_max - _M_min + 1)) + _M_min; } | |
1322 | ||
1323 | /** | |
1324 | * Gets a uniform random number in the range @f$[0, n)@f$. | |
1325 | * | |
1326 | * This function is aimed at use with std::random_shuffle. | |
1327 | */ | |
1328 | template<typename _UniformRandomNumberGenerator> | |
1329 | result_type | |
1330 | operator()(_UniformRandomNumberGenerator& __urng, result_type __n) | |
1331 | { return __urng() % __n; } | |
1332 | ||
1333 | /** | |
d95c1c48 | 1334 | * Inserts a %uniform_int random number distribution @p __x into the |
86ad0dd6 PC |
1335 | * output stream @p os. |
1336 | * | |
1337 | * @param __os An output stream. | |
1338 | * @param __x A %uniform_int random number distribution. | |
1339 | * | |
d95c1c48 PC |
1340 | * @returns The output stream with the state of @p __x inserted or in |
1341 | * an error state. | |
86ad0dd6 PC |
1342 | */ |
1343 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1344 | friend std::basic_ostream<_CharT, _Traits>& |
1345 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 PC |
1346 | const uniform_int& __x) |
1347 | { return __os << __x._M_min << " " << __x._M_max; } | |
1348 | ||
1349 | /** | |
1350 | * Extracts a %unform_int random number distribution | |
d95c1c48 | 1351 | * @p __u from the input stream @p __is. |
86ad0dd6 PC |
1352 | * |
1353 | * @param __is An input stream. | |
1354 | * @param __u A %uniform_int random number generator engine. | |
1355 | * | |
d95c1c48 | 1356 | * @returns The input stream with @p __u extracted or in an error state. |
86ad0dd6 PC |
1357 | */ |
1358 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1359 | friend std::basic_istream<_CharT, _Traits>& |
1360 | operator>>(std::basic_istream<_CharT, _Traits>& __is, uniform_int& __u) | |
86ad0dd6 PC |
1361 | { return __is >> __u._M_min >> __u._M_max; } |
1362 | ||
1363 | private: | |
1364 | _IntType _M_min; | |
1365 | _IntType _M_max; | |
1366 | }; | |
1367 | ||
1368 | ||
1369 | /** | |
1370 | * @brief A Bernoulli random number distribution. | |
1371 | * | |
1372 | * Generates a sequence of true and false values with likelihood @f$ p @f$ | |
1373 | * that true will come up and @f$ (1 - p) @f$ that false will appear. | |
1374 | */ | |
1375 | class bernoulli_distribution | |
1376 | { | |
1377 | public: | |
1378 | typedef int input_type; | |
1379 | typedef bool result_type; | |
1380 | ||
1381 | public: | |
1382 | /** | |
1383 | * Constructs a Bernoulli distribution with likelihood @p p. | |
1384 | * | |
281864aa | 1385 | * @param __p [IN] The likelihood of a true result being returned. Must |
86ad0dd6 PC |
1386 | * be in the interval @f$ [0, 1] @f$. |
1387 | */ | |
1388 | explicit | |
1389 | bernoulli_distribution(double __p = 0.5) | |
1390 | : _M_p(__p) | |
1391 | { | |
1392 | _GLIBCXX_DEBUG_ASSERT((_M_p >= 0.0) && (_M_p <= 1.0)); | |
1393 | } | |
1394 | ||
1395 | /** | |
1396 | * Gets the @p p parameter of the distribution. | |
1397 | */ | |
1398 | double | |
1399 | p() const | |
1400 | { return _M_p; } | |
1401 | ||
1402 | /** | |
1403 | * Gets the inclusive lower bound of the distribution range. | |
1404 | */ | |
1405 | result_type | |
1406 | min() const | |
1407 | { return false; } | |
1408 | ||
1409 | /** | |
1410 | * Gets the inclusive upper bound of the distribution range. | |
1411 | */ | |
1412 | result_type | |
1413 | max() const | |
1414 | { return true; } | |
1415 | ||
1416 | /** | |
1417 | * Resets the distribution state. | |
1418 | * | |
1419 | * Does nothing for a bernoulli distribution. | |
1420 | */ | |
1421 | void | |
1422 | reset() { } | |
1423 | ||
1424 | /** | |
1425 | * Gets the next value in the Bernoullian sequence. | |
1426 | */ | |
1427 | template<class UniformRandomNumberGenerator> | |
1428 | result_type | |
1429 | operator()(UniformRandomNumberGenerator& __urng) | |
1430 | { | |
1431 | if (__urng() < _M_p) | |
1432 | return true; | |
1433 | return false; | |
1434 | } | |
1435 | ||
1436 | /** | |
1437 | * Inserts a %bernoulli_distribution random number distribution | |
d95c1c48 | 1438 | * @p __x into the output stream @p __os. |
86ad0dd6 PC |
1439 | * |
1440 | * @param __os An output stream. | |
1441 | * @param __x A %bernoulli_distribution random number distribution. | |
1442 | * | |
d95c1c48 PC |
1443 | * @returns The output stream with the state of @p __x inserted or in |
1444 | * an error state. | |
86ad0dd6 PC |
1445 | */ |
1446 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1447 | friend std::basic_ostream<_CharT, _Traits>& |
1448 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 PC |
1449 | const bernoulli_distribution& __x) |
1450 | { return __os << __x.p(); } | |
1451 | ||
1452 | /** | |
1453 | * Extracts a %bernoulli_distribution random number distribution | |
d95c1c48 | 1454 | * @p __u from the input stream @p __is. |
86ad0dd6 PC |
1455 | * |
1456 | * @param __is An input stream. | |
1457 | * @param __u A %bernoulli_distribution random number generator engine. | |
1458 | * | |
d95c1c48 | 1459 | * @returns The input stream with @p __u extracted or in an error state. |
86ad0dd6 PC |
1460 | */ |
1461 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1462 | friend std::basic_istream<_CharT, _Traits>& |
1463 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
86ad0dd6 PC |
1464 | bernoulli_distribution& __u) |
1465 | { return __is >> __u._M_p; } | |
1466 | ||
1467 | protected: | |
1468 | double _M_p; | |
1469 | }; | |
1470 | ||
1471 | ||
1472 | /** | |
1473 | * @brief A discrete geometric random number distribution. | |
1474 | * | |
1475 | * The formula for the geometric probability mass function is | |
1476 | * @f$ p(i) = (1 - p)p^{i-1} @f$ where @f$ p @f$ is the parameter of the | |
1477 | * distribution. | |
1478 | */ | |
1479 | template<typename _IntType = int, typename _RealType = double> | |
1480 | class geometric_distribution | |
1481 | { | |
1482 | public: | |
1483 | // types | |
1484 | typedef _RealType input_type; | |
1485 | typedef _IntType result_type; | |
1486 | ||
1487 | // constructors and member function | |
1488 | ||
1489 | explicit | |
1490 | geometric_distribution(const _RealType& __p = _RealType(0.5)) | |
1491 | : _M_p(__p), _M_log_p(std::log(_M_p)) | |
1492 | { | |
1493 | _GLIBCXX_DEBUG_ASSERT((_M_p >= 0.0) && (_M_p <= 1.0)); | |
1494 | } | |
1495 | ||
1496 | /** | |
281864aa | 1497 | * Gets the distribution parameter @p p. |
86ad0dd6 PC |
1498 | */ |
1499 | _RealType | |
1500 | p() const | |
1501 | { return _M_p; } | |
1502 | ||
1503 | /** | |
1504 | * Gets the inclusive lower bound of the distribution range. | |
1505 | */ | |
1506 | result_type | |
1507 | min() const; | |
1508 | ||
1509 | /** | |
1510 | * Gets the inclusive upper bound of the distribution range. | |
1511 | */ | |
1512 | result_type | |
1513 | max() const; | |
1514 | ||
1515 | void | |
1516 | reset() { } | |
1517 | ||
1518 | template<class _UniformRandomNumberGenerator> | |
1519 | result_type | |
1520 | operator()(_UniformRandomNumberGenerator& __urng) | |
1521 | { | |
1522 | return result_type(std::floor(std::log(_RealType(1.0) - __urng()) | |
1523 | / _M_log_p)) + result_type(1); | |
1524 | } | |
1525 | ||
1526 | /** | |
1527 | * Inserts a %geometric_distribution random number distribution | |
d95c1c48 | 1528 | * @p __x into the output stream @p __os. |
86ad0dd6 PC |
1529 | * |
1530 | * @param __os An output stream. | |
1531 | * @param __x A %geometric_distribution random number distribution. | |
1532 | * | |
d95c1c48 PC |
1533 | * @returns The output stream with the state of @p __x inserted or in |
1534 | * an error state. | |
86ad0dd6 PC |
1535 | */ |
1536 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1537 | friend std::basic_ostream<_CharT, _Traits>& |
1538 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 PC |
1539 | const geometric_distribution& __x) |
1540 | { return __os << __x.p(); } | |
1541 | ||
1542 | /** | |
1543 | * Extracts a %geometric_distribution random number distribution | |
d95c1c48 | 1544 | * @p __u from the input stream @p __is. |
86ad0dd6 PC |
1545 | * |
1546 | * @param __is An input stream. | |
1547 | * @param __u A %geometric_distribution random number generator engine. | |
1548 | * | |
d95c1c48 | 1549 | * @returns The input stream with @p __u extracted or in an error state. |
86ad0dd6 PC |
1550 | */ |
1551 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1552 | friend std::basic_istream<_CharT, _Traits>& |
1553 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
86ad0dd6 PC |
1554 | geometric_distribution& __u) |
1555 | { | |
1556 | __is >> __u._M_p; | |
1557 | __u._M_log_p = std::log(__u._M_p); | |
1558 | return __is; | |
1559 | } | |
1560 | ||
1561 | protected: | |
1562 | _RealType _M_p; | |
1563 | _RealType _M_log_p; | |
1564 | }; | |
1565 | ||
1566 | /* @} */ // group tr1_random_distributions_discrete | |
1567 | ||
1568 | /** | |
1569 | * @addtogroup tr1_random_distributions_continuous Continuous Distributions | |
1570 | * @ingroup tr1_random_distributions | |
1571 | * @{ | |
1572 | */ | |
1573 | ||
1574 | /** | |
1575 | * @brief Uniform continuous distribution for random numbers. | |
1576 | * | |
1577 | * A continuous random distribution on the range [min, max) with equal | |
1578 | * probability throughout the range. The URNG should be real-valued and | |
1579 | * deliver number in the range [0, 1). | |
1580 | */ | |
1581 | template<typename _RealType = double> | |
1582 | class uniform_real | |
1583 | { | |
1584 | public: | |
1585 | // types | |
1586 | typedef _RealType input_type; | |
1587 | typedef _RealType result_type; | |
1588 | ||
1589 | public: | |
1590 | /** | |
1591 | * Constructs a uniform_real object. | |
1592 | * | |
281864aa PC |
1593 | * @param __min [IN] The lower bound of the distribution. |
1594 | * @param __max [IN] The upper bound of the distribution. | |
86ad0dd6 PC |
1595 | */ |
1596 | explicit | |
281864aa | 1597 | uniform_real(_RealType __min = _RealType(0), |
0934c5ef PC |
1598 | _RealType __max = _RealType(1)) |
1599 | : _M_min(__min), _M_max(__max) | |
1600 | { | |
1601 | _GLIBCXX_DEBUG_ASSERT(_M_min <= _M_max); | |
1602 | } | |
86ad0dd6 PC |
1603 | |
1604 | result_type | |
0934c5ef PC |
1605 | min() const |
1606 | { return _M_min; } | |
86ad0dd6 PC |
1607 | |
1608 | result_type | |
0934c5ef PC |
1609 | max() const |
1610 | { return _M_max; } | |
86ad0dd6 | 1611 | |
0934c5ef PC |
1612 | void |
1613 | reset() { } | |
86ad0dd6 PC |
1614 | |
1615 | template<class _UniformRandomNumberGenerator> | |
1616 | result_type | |
1617 | operator()(_UniformRandomNumberGenerator& __urng) | |
0934c5ef | 1618 | { return (__urng() * (_M_max - _M_min)) + _M_min; } |
86ad0dd6 PC |
1619 | |
1620 | /** | |
d95c1c48 | 1621 | * Inserts a %uniform_real random number distribution @p __x into the |
281864aa | 1622 | * output stream @p __os. |
86ad0dd6 PC |
1623 | * |
1624 | * @param __os An output stream. | |
1625 | * @param __x A %uniform_real random number distribution. | |
1626 | * | |
d95c1c48 PC |
1627 | * @returns The output stream with the state of @p __x inserted or in |
1628 | * an error state. | |
86ad0dd6 PC |
1629 | */ |
1630 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1631 | friend std::basic_ostream<_CharT, _Traits>& |
1632 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 | 1633 | const uniform_real& __x) |
0934c5ef | 1634 | { return __os << __x._M_min << " " << __x._M_max; } |
86ad0dd6 PC |
1635 | |
1636 | /** | |
1637 | * Extracts a %unform_real random number distribution | |
d95c1c48 | 1638 | * @p __u from the input stream @p __is. |
86ad0dd6 PC |
1639 | * |
1640 | * @param __is An input stream. | |
1641 | * @param __u A %uniform_real random number generator engine. | |
1642 | * | |
d95c1c48 | 1643 | * @returns The input stream with @p __u extracted or in an error state. |
86ad0dd6 PC |
1644 | */ |
1645 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1646 | friend std::basic_istream<_CharT, _Traits>& |
1647 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
1648 | uniform_real& __u) | |
86ad0dd6 PC |
1649 | { return __is >> __u._M_min >> __u._M_max; } |
1650 | ||
1651 | protected: | |
1652 | _RealType _M_min; | |
1653 | _RealType _M_max; | |
1654 | }; | |
1655 | ||
1656 | ||
1657 | /** | |
1658 | * @brief An exponential continuous distribution for random numbers. | |
1659 | * | |
1660 | * The formula for the exponential probability mass function is | |
1661 | * @f$ p(x) = \lambda e^{-\lambda x} @f$. | |
1662 | * | |
1663 | * <table border=1 cellpadding=10 cellspacing=0> | |
1664 | * <caption align=top>Distribution Statistics</caption> | |
1665 | * <tr><td>Mean</td><td>@f$ \frac{1}{\lambda} @f$</td></tr> | |
1666 | * <tr><td>Median</td><td>@f$ \frac{\ln 2}{\lambda} @f$</td></tr> | |
1667 | * <tr><td>Mode</td><td>@f$ zero @f$</td></tr> | |
1668 | * <tr><td>Range</td><td>@f$[0, \infty]@f$</td></tr> | |
1669 | * <tr><td>Standard Deviation</td><td>@f$ \frac{1}{\lambda} @f$</td></tr> | |
1670 | * </table> | |
1671 | */ | |
1672 | template<typename _RealType = double> | |
1673 | class exponential_distribution | |
1674 | { | |
1675 | public: | |
1676 | // types | |
1677 | typedef _RealType input_type; | |
1678 | typedef _RealType result_type; | |
1679 | ||
1680 | public: | |
1681 | /** | |
1682 | * Constructs an exponential distribution with inverse scale parameter | |
1683 | * @f$ \lambda @f$. | |
1684 | */ | |
1685 | explicit | |
1686 | exponential_distribution(const result_type& __lambda = result_type(1)) | |
1687 | : _M_lambda(__lambda) { } | |
1688 | ||
1689 | /** | |
1690 | * Gets the inverse scale parameter of the distribution. | |
1691 | */ | |
1692 | _RealType | |
1693 | lambda() const | |
1694 | { return _M_lambda; } | |
1695 | ||
1696 | /** | |
1697 | * Resets the distribution. | |
1698 | * | |
1699 | * Has no effect on exponential distributions. | |
1700 | */ | |
1701 | void | |
1702 | reset() { } | |
1703 | ||
1704 | template<class _UniformRandomNumberGenerator> | |
1705 | result_type | |
1706 | operator()(_UniformRandomNumberGenerator& __urng) | |
36ac3ed6 | 1707 | { return -std::log(__urng()) / _M_lambda; } |
86ad0dd6 PC |
1708 | |
1709 | /** | |
1710 | * Inserts a %exponential_distribution random number distribution | |
d95c1c48 | 1711 | * @p __x into the output stream @p __os. |
86ad0dd6 PC |
1712 | * |
1713 | * @param __os An output stream. | |
1714 | * @param __x A %exponential_distribution random number distribution. | |
1715 | * | |
d95c1c48 PC |
1716 | * @returns The output stream with the state of @p __x inserted or in |
1717 | * an error state. | |
86ad0dd6 PC |
1718 | */ |
1719 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1720 | friend std::basic_ostream<_CharT, _Traits>& |
1721 | operator<<(std::basic_ostream<_CharT, _Traits>& __os, | |
86ad0dd6 PC |
1722 | const exponential_distribution& __x) |
1723 | { return __os << __x.lambda(); } | |
1724 | ||
1725 | /** | |
1726 | * Extracts a %exponential_distribution random number distribution | |
d95c1c48 | 1727 | * @p __u from the input stream @p __is. |
86ad0dd6 PC |
1728 | * |
1729 | * @param __is An input stream. | |
1730 | * @param __u A %exponential_distribution random number generator engine. | |
1731 | * | |
d95c1c48 | 1732 | * @returns The input stream with @p __u extracted or in an error state. |
86ad0dd6 PC |
1733 | */ |
1734 | template<typename _CharT, typename _Traits> | |
410fce92 PC |
1735 | friend std::basic_istream<_CharT, _Traits>& |
1736 | operator>>(std::basic_istream<_CharT, _Traits>& __is, | |
86ad0dd6 PC |
1737 | exponential_distribution& __u) |
1738 | { return __is >> __u._M_lambda; } | |
1739 | ||
1740 | private: | |
1741 | result_type _M_lambda; | |
1742 | }; | |
1743 | ||
1744 | /* @} */ // group tr1_random_distributions_continuous | |
1745 | /* @} */ // group tr1_random_distributions | |
1746 | /* @} */ // group tr1_random | |
1747 | ||
1748 | _GLIBCXX_END_NAMESPACE | |
1749 | } | |
1750 | ||
1751 | #include <tr1/random.tcc> | |
1752 | ||
1753 | #endif // _STD_TR1_RANDOM |