xref: /freebsd-12.1/contrib/libc++/include/random (revision 4e7dc6ec)
1// -*- C++ -*-
2//===--------------------------- random -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_RANDOM
12#define _LIBCPP_RANDOM
13
14/*
15    random synopsis
16
17#include <initializer_list>
18
19namespace std
20{
21
22// Engines
23
24template <class UIntType, UIntType a, UIntType c, UIntType m>
25class linear_congruential_engine
26{
27public:
28    // types
29    typedef UIntType result_type;
30
31    // engine characteristics
32    static constexpr result_type multiplier = a;
33    static constexpr result_type increment = c;
34    static constexpr result_type modulus = m;
35    static constexpr result_type min() { return c == 0u ? 1u: 0u;}
36    static constexpr result_type max() { return m - 1u;}
37    static constexpr result_type default_seed = 1u;
38
39    // constructors and seeding functions
40    explicit linear_congruential_engine(result_type s = default_seed);
41    template<class Sseq> explicit linear_congruential_engine(Sseq& q);
42    void seed(result_type s = default_seed);
43    template<class Sseq> void seed(Sseq& q);
44
45    // generating functions
46    result_type operator()();
47    void discard(unsigned long long z);
48};
49
50template <class UIntType, UIntType a, UIntType c, UIntType m>
51bool
52operator==(const linear_congruential_engine<UIntType, a, c, m>& x,
53           const linear_congruential_engine<UIntType, a, c, m>& y);
54
55template <class UIntType, UIntType a, UIntType c, UIntType m>
56bool
57operator!=(const linear_congruential_engine<UIntType, a, c, m>& x,
58           const linear_congruential_engine<UIntType, a, c, m>& y);
59
60template <class charT, class traits,
61          class UIntType, UIntType a, UIntType c, UIntType m>
62basic_ostream<charT, traits>&
63operator<<(basic_ostream<charT, traits>& os,
64           const linear_congruential_engine<UIntType, a, c, m>& x);
65
66template <class charT, class traits,
67          class UIntType, UIntType a, UIntType c, UIntType m>
68basic_istream<charT, traits>&
69operator>>(basic_istream<charT, traits>& is,
70           linear_congruential_engine<UIntType, a, c, m>& x);
71
72template <class UIntType, size_t w, size_t n, size_t m, size_t r,
73          UIntType a, size_t u, UIntType d, size_t s,
74          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
75class mersenne_twister_engine
76{
77public:
78    // types
79    typedef UIntType result_type;
80
81    // engine characteristics
82    static constexpr size_t word_size = w;
83    static constexpr size_t state_size = n;
84    static constexpr size_t shift_size = m;
85    static constexpr size_t mask_bits = r;
86    static constexpr result_type xor_mask = a;
87    static constexpr size_t tempering_u = u;
88    static constexpr result_type tempering_d = d;
89    static constexpr size_t tempering_s = s;
90    static constexpr result_type tempering_b = b;
91    static constexpr size_t tempering_t = t;
92    static constexpr result_type tempering_c = c;
93    static constexpr size_t tempering_l = l;
94    static constexpr result_type initialization_multiplier = f;
95    static constexpr result_type min () { return 0; }
96    static constexpr result_type max() { return 2^w - 1; }
97    static constexpr result_type default_seed = 5489u;
98
99    // constructors and seeding functions
100    explicit mersenne_twister_engine(result_type value = default_seed);
101    template<class Sseq> explicit mersenne_twister_engine(Sseq& q);
102    void seed(result_type value = default_seed);
103    template<class Sseq> void seed(Sseq& q);
104
105    // generating functions
106    result_type operator()();
107    void discard(unsigned long long z);
108};
109
110template <class UIntType, size_t w, size_t n, size_t m, size_t r,
111          UIntType a, size_t u, UIntType d, size_t s,
112          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
113bool
114operator==(
115    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x,
116    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& y);
117
118template <class UIntType, size_t w, size_t n, size_t m, size_t r,
119          UIntType a, size_t u, UIntType d, size_t s,
120          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
121bool
122operator!=(
123    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x,
124    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& y);
125
126template <class charT, class traits,
127          class UIntType, size_t w, size_t n, size_t m, size_t r,
128          UIntType a, size_t u, UIntType d, size_t s,
129          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
130basic_ostream<charT, traits>&
131operator<<(basic_ostream<charT, traits>& os,
132           const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x);
133
134template <class charT, class traits,
135          class UIntType, size_t w, size_t n, size_t m, size_t r,
136          UIntType a, size_t u, UIntType d, size_t s,
137          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
138basic_istream<charT, traits>&
139operator>>(basic_istream<charT, traits>& is,
140           mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x);
141
142template<class UIntType, size_t w, size_t s, size_t r>
143class subtract_with_carry_engine
144{
145public:
146    // types
147    typedef UIntType result_type;
148
149    // engine characteristics
150    static constexpr size_t word_size = w;
151    static constexpr size_t short_lag = s;
152    static constexpr size_t long_lag = r;
153    static constexpr result_type min() { return 0; }
154    static constexpr result_type max() { return m-1; }
155    static constexpr result_type default_seed = 19780503u;
156
157    // constructors and seeding functions
158    explicit subtract_with_carry_engine(result_type value = default_seed);
159    template<class Sseq> explicit subtract_with_carry_engine(Sseq& q);
160    void seed(result_type value = default_seed);
161    template<class Sseq> void seed(Sseq& q);
162
163    // generating functions
164    result_type operator()();
165    void discard(unsigned long long z);
166};
167
168template<class UIntType, size_t w, size_t s, size_t r>
169bool
170operator==(
171    const subtract_with_carry_engine<UIntType, w, s, r>& x,
172    const subtract_with_carry_engine<UIntType, w, s, r>& y);
173
174template<class UIntType, size_t w, size_t s, size_t r>
175bool
176operator!=(
177    const subtract_with_carry_engine<UIntType, w, s, r>& x,
178    const subtract_with_carry_engine<UIntType, w, s, r>& y);
179
180template <class charT, class traits,
181          class UIntType, size_t w, size_t s, size_t r>
182basic_ostream<charT, traits>&
183operator<<(basic_ostream<charT, traits>& os,
184           const subtract_with_carry_engine<UIntType, w, s, r>& x);
185
186template <class charT, class traits,
187          class UIntType, size_t w, size_t s, size_t r>
188basic_istream<charT, traits>&
189operator>>(basic_istream<charT, traits>& is,
190           subtract_with_carry_engine<UIntType, w, s, r>& x);
191
192template<class Engine, size_t p, size_t r>
193class discard_block_engine
194{
195public:
196    // types
197    typedef typename Engine::result_type result_type;
198
199    // engine characteristics
200    static constexpr size_t block_size = p;
201    static constexpr size_t used_block = r;
202    static constexpr result_type min() { return Engine::min(); }
203    static constexpr result_type max() { return Engine::max(); }
204
205    // constructors and seeding functions
206    discard_block_engine();
207    explicit discard_block_engine(const Engine& e);
208    explicit discard_block_engine(Engine&& e);
209    explicit discard_block_engine(result_type s);
210    template<class Sseq> explicit discard_block_engine(Sseq& q);
211    void seed();
212    void seed(result_type s);
213    template<class Sseq> void seed(Sseq& q);
214
215    // generating functions
216    result_type operator()();
217    void discard(unsigned long long z);
218
219    // property functions
220    const Engine& base() const;
221};
222
223template<class Engine, size_t p, size_t r>
224bool
225operator==(
226    const discard_block_engine<Engine, p, r>& x,
227    const discard_block_engine<Engine, p, r>& y);
228
229template<class Engine, size_t p, size_t r>
230bool
231operator!=(
232    const discard_block_engine<Engine, p, r>& x,
233    const discard_block_engine<Engine, p, r>& y);
234
235template <class charT, class traits,
236          class Engine, size_t p, size_t r>
237basic_ostream<charT, traits>&
238operator<<(basic_ostream<charT, traits>& os,
239           const discard_block_engine<Engine, p, r>& x);
240
241template <class charT, class traits,
242          class Engine, size_t p, size_t r>
243basic_istream<charT, traits>&
244operator>>(basic_istream<charT, traits>& is,
245           discard_block_engine<Engine, p, r>& x);
246
247template<class Engine, size_t w, class UIntType>
248class independent_bits_engine
249{
250public:
251    // types
252    typedef UIntType result_type;
253
254    // engine characteristics
255    static constexpr result_type min() { return 0; }
256    static constexpr result_type max() { return 2^w - 1; }
257
258    // constructors and seeding functions
259    independent_bits_engine();
260    explicit independent_bits_engine(const Engine& e);
261    explicit independent_bits_engine(Engine&& e);
262    explicit independent_bits_engine(result_type s);
263    template<class Sseq> explicit independent_bits_engine(Sseq& q);
264    void seed();
265    void seed(result_type s);
266    template<class Sseq> void seed(Sseq& q);
267
268    // generating functions
269    result_type operator()(); void discard(unsigned long long z);
270
271    // property functions
272    const Engine& base() const;
273};
274
275template<class Engine, size_t w, class UIntType>
276bool
277operator==(
278    const independent_bits_engine<Engine, w, UIntType>& x,
279    const independent_bits_engine<Engine, w, UIntType>& y);
280
281template<class Engine, size_t w, class UIntType>
282bool
283operator!=(
284    const independent_bits_engine<Engine, w, UIntType>& x,
285    const independent_bits_engine<Engine, w, UIntType>& y);
286
287template <class charT, class traits,
288          class Engine, size_t w, class UIntType>
289basic_ostream<charT, traits>&
290operator<<(basic_ostream<charT, traits>& os,
291           const independent_bits_engine<Engine, w, UIntType>& x);
292
293template <class charT, class traits,
294          class Engine, size_t w, class UIntType>
295basic_istream<charT, traits>&
296operator>>(basic_istream<charT, traits>& is,
297           independent_bits_engine<Engine, w, UIntType>& x);
298
299template<class Engine, size_t k>
300class shuffle_order_engine
301{
302public:
303    // types
304    typedef typename Engine::result_type result_type;
305
306    // engine characteristics
307    static constexpr size_t table_size = k;
308    static constexpr result_type min() { return Engine::min; }
309    static constexpr result_type max() { return Engine::max; }
310
311    // constructors and seeding functions
312    shuffle_order_engine();
313    explicit shuffle_order_engine(const Engine& e);
314    explicit shuffle_order_engine(Engine&& e);
315    explicit shuffle_order_engine(result_type s);
316    template<class Sseq> explicit shuffle_order_engine(Sseq& q);
317    void seed();
318    void seed(result_type s);
319    template<class Sseq> void seed(Sseq& q);
320
321    // generating functions
322    result_type operator()();
323    void discard(unsigned long long z);
324
325    // property functions
326    const Engine& base() const;
327};
328
329template<class Engine, size_t k>
330bool
331operator==(
332    const shuffle_order_engine<Engine, k>& x,
333    const shuffle_order_engine<Engine, k>& y);
334
335template<class Engine, size_t k>
336bool
337operator!=(
338    const shuffle_order_engine<Engine, k>& x,
339    const shuffle_order_engine<Engine, k>& y);
340
341template <class charT, class traits,
342          class Engine, size_t k>
343basic_ostream<charT, traits>&
344operator<<(basic_ostream<charT, traits>& os,
345           const shuffle_order_engine<Engine, k>& x);
346
347template <class charT, class traits,
348          class Engine, size_t k>
349basic_istream<charT, traits>&
350operator>>(basic_istream<charT, traits>& is,
351           shuffle_order_engine<Engine, k>& x);
352
353typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
354                                                                   minstd_rand0;
355typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
356                                                                    minstd_rand;
357typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
358                                0x9908b0df,
359                                11, 0xffffffff,
360                                7,  0x9d2c5680,
361                                15, 0xefc60000,
362                                18, 1812433253>                         mt19937;
363typedef mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
364                                0xb5026f5aa96619e9,
365                                29, 0x5555555555555555,
366                                17, 0x71d67fffeda60000,
367                                37, 0xfff7eee000000000,
368                                43, 6364136223846793005>             mt19937_64;
369typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>     ranlux24_base;
370typedef subtract_with_carry_engine<uint_fast64_t, 48,  5, 12>     ranlux48_base;
371typedef discard_block_engine<ranlux24_base, 223, 23>                   ranlux24;
372typedef discard_block_engine<ranlux48_base, 389, 11>                   ranlux48;
373typedef shuffle_order_engine<minstd_rand0, 256>                         knuth_b;
374typedef minstd_rand                                       default_random_engine;
375
376// Generators
377
378class random_device
379{
380public:
381    // types
382    typedef unsigned int result_type;
383
384    // generator characteristics
385    static constexpr result_type min() { return numeric_limits<result_type>::min(); }
386    static constexpr result_type max() { return numeric_limits<result_type>::max(); }
387
388    // constructors
389    explicit random_device(const string& token = "/dev/urandom");
390
391    // generating functions
392    result_type operator()();
393
394    // property functions
395    double entropy() const;
396
397    // no copy functions
398    random_device(const random_device& ) = delete;
399    void operator=(const random_device& ) = delete;
400};
401
402// Utilities
403
404class seed_seq
405{
406public:
407    // types
408    typedef uint_least32_t result_type;
409
410    // constructors
411    seed_seq();
412    template<class T>
413        seed_seq(initializer_list<T> il);
414    template<class InputIterator>
415        seed_seq(InputIterator begin, InputIterator end);
416
417    // generating functions
418    template<class RandomAccessIterator>
419        void generate(RandomAccessIterator begin, RandomAccessIterator end);
420
421    // property functions
422    size_t size() const;
423    template<class OutputIterator>
424        void param(OutputIterator dest) const;
425
426    // no copy functions
427    seed_seq(const seed_seq&) = delete;
428    void operator=(const seed_seq& ) = delete;
429};
430
431template<class RealType, size_t bits, class URNG>
432    RealType generate_canonical(URNG& g);
433
434// Distributions
435
436template<class IntType = int>
437class uniform_int_distribution
438{
439public:
440    // types
441    typedef IntType result_type;
442
443    class param_type
444    {
445    public:
446        typedef uniform_int_distribution distribution_type;
447
448        explicit param_type(IntType a = 0,
449                                    IntType b = numeric_limits<IntType>::max());
450
451        result_type a() const;
452        result_type b() const;
453
454        friend bool operator==(const param_type& x, const param_type& y);
455        friend bool operator!=(const param_type& x, const param_type& y);
456    };
457
458    // constructors and reset functions
459    explicit uniform_int_distribution(IntType a = 0,
460                                    IntType b = numeric_limits<IntType>::max());
461    explicit uniform_int_distribution(const param_type& parm);
462    void reset();
463
464    // generating functions
465    template<class URNG> result_type operator()(URNG& g);
466    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
467
468    // property functions
469    result_type a() const;
470    result_type b() const;
471
472    param_type param() const;
473    void param(const param_type& parm);
474
475    result_type min() const;
476    result_type max() const;
477
478    friend bool operator==(const uniform_int_distribution& x,
479                           const uniform_int_distribution& y);
480    friend bool operator!=(const uniform_int_distribution& x,
481                           const uniform_int_distribution& y);
482
483    template <class charT, class traits>
484    friend
485    basic_ostream<charT, traits>&
486    operator<<(basic_ostream<charT, traits>& os,
487               const uniform_int_distribution& x);
488
489    template <class charT, class traits>
490    friend
491    basic_istream<charT, traits>&
492    operator>>(basic_istream<charT, traits>& is,
493               uniform_int_distribution& x);
494};
495
496template<class RealType = double>
497class uniform_real_distribution
498{
499public:
500    // types
501    typedef RealType result_type;
502
503    class param_type
504    {
505    public:
506        typedef uniform_real_distribution distribution_type;
507
508        explicit param_type(RealType a = 0,
509                            RealType b = 1);
510
511        result_type a() const;
512        result_type b() const;
513
514        friend bool operator==(const param_type& x, const param_type& y);
515        friend bool operator!=(const param_type& x, const param_type& y);
516    };
517
518    // constructors and reset functions
519    explicit uniform_real_distribution(RealType a = 0.0, RealType b = 1.0);
520    explicit uniform_real_distribution(const param_type& parm);
521    void reset();
522
523    // generating functions
524    template<class URNG> result_type operator()(URNG& g);
525    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
526
527    // property functions
528    result_type a() const;
529    result_type b() const;
530
531    param_type param() const;
532    void param(const param_type& parm);
533
534    result_type min() const;
535    result_type max() const;
536
537    friend bool operator==(const uniform_real_distribution& x,
538                           const uniform_real_distribution& y);
539    friend bool operator!=(const uniform_real_distribution& x,
540                           const uniform_real_distribution& y);
541
542    template <class charT, class traits>
543    friend
544    basic_ostream<charT, traits>&
545    operator<<(basic_ostream<charT, traits>& os,
546               const uniform_real_distribution& x);
547
548    template <class charT, class traits>
549    friend
550    basic_istream<charT, traits>&
551    operator>>(basic_istream<charT, traits>& is,
552               uniform_real_distribution& x);
553};
554
555class bernoulli_distribution
556{
557public:
558    // types
559    typedef bool result_type;
560
561    class param_type
562    {
563    public:
564        typedef bernoulli_distribution distribution_type;
565
566        explicit param_type(double p = 0.5);
567
568        double p() const;
569
570        friend bool operator==(const param_type& x, const param_type& y);
571        friend bool operator!=(const param_type& x, const param_type& y);
572    };
573
574    // constructors and reset functions
575    explicit bernoulli_distribution(double p = 0.5);
576    explicit bernoulli_distribution(const param_type& parm);
577    void reset();
578
579    // generating functions
580    template<class URNG> result_type operator()(URNG& g);
581    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
582
583    // property functions
584    double p() const;
585
586    param_type param() const;
587    void param(const param_type& parm);
588
589    result_type min() const;
590    result_type max() const;
591
592    friend bool operator==(const bernoulli_distribution& x,
593                           const bernoulli_distribution& y);
594    friend bool operator!=(const bernoulli_distribution& x,
595                           const bernoulli_distribution& y);
596
597    template <class charT, class traits>
598    friend
599    basic_ostream<charT, traits>&
600    operator<<(basic_ostream<charT, traits>& os,
601               const bernoulli_distribution& x);
602
603    template <class charT, class traits>
604    friend
605    basic_istream<charT, traits>&
606    operator>>(basic_istream<charT, traits>& is,
607               bernoulli_distribution& x);
608};
609
610template<class IntType = int>
611class binomial_distribution
612{
613public:
614    // types
615    typedef IntType result_type;
616
617    class param_type
618    {
619    public:
620        typedef binomial_distribution distribution_type;
621
622        explicit param_type(IntType t = 1, double p = 0.5);
623
624        IntType t() const;
625        double p() const;
626
627        friend bool operator==(const param_type& x, const param_type& y);
628        friend bool operator!=(const param_type& x, const param_type& y);
629    };
630
631    // constructors and reset functions
632    explicit binomial_distribution(IntType t = 1, double p = 0.5);
633    explicit binomial_distribution(const param_type& parm);
634    void reset();
635
636    // generating functions
637    template<class URNG> result_type operator()(URNG& g);
638    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
639
640    // property functions
641    IntType t() const;
642    double p() const;
643
644    param_type param() const;
645    void param(const param_type& parm);
646
647    result_type min() const;
648    result_type max() const;
649
650    friend bool operator==(const binomial_distribution& x,
651                           const binomial_distribution& y);
652    friend bool operator!=(const binomial_distribution& x,
653                           const binomial_distribution& y);
654
655    template <class charT, class traits>
656    friend
657    basic_ostream<charT, traits>&
658    operator<<(basic_ostream<charT, traits>& os,
659               const binomial_distribution& x);
660
661    template <class charT, class traits>
662    friend
663    basic_istream<charT, traits>&
664    operator>>(basic_istream<charT, traits>& is,
665               binomial_distribution& x);
666};
667
668template<class IntType = int>
669class geometric_distribution
670{
671public:
672    // types
673    typedef IntType result_type;
674
675    class param_type
676    {
677    public:
678        typedef geometric_distribution distribution_type;
679
680        explicit param_type(double p = 0.5);
681
682        double p() const;
683
684        friend bool operator==(const param_type& x, const param_type& y);
685        friend bool operator!=(const param_type& x, const param_type& y);
686    };
687
688    // constructors and reset functions
689    explicit geometric_distribution(double p = 0.5);
690    explicit geometric_distribution(const param_type& parm);
691    void reset();
692
693    // generating functions
694    template<class URNG> result_type operator()(URNG& g);
695    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
696
697    // property functions
698    double p() const;
699
700    param_type param() const;
701    void param(const param_type& parm);
702
703    result_type min() const;
704    result_type max() const;
705
706    friend bool operator==(const geometric_distribution& x,
707                           const geometric_distribution& y);
708    friend bool operator!=(const geometric_distribution& x,
709                           const geometric_distribution& y);
710
711    template <class charT, class traits>
712    friend
713    basic_ostream<charT, traits>&
714    operator<<(basic_ostream<charT, traits>& os,
715               const geometric_distribution& x);
716
717    template <class charT, class traits>
718    friend
719    basic_istream<charT, traits>&
720    operator>>(basic_istream<charT, traits>& is,
721               geometric_distribution& x);
722};
723
724template<class IntType = int>
725class negative_binomial_distribution
726{
727public:
728    // types
729    typedef IntType result_type;
730
731    class param_type
732    {
733    public:
734        typedef negative_binomial_distribution distribution_type;
735
736        explicit param_type(result_type k = 1, double p = 0.5);
737
738        result_type k() const;
739        double p() const;
740
741        friend bool operator==(const param_type& x, const param_type& y);
742        friend bool operator!=(const param_type& x, const param_type& y);
743    };
744
745    // constructor and reset functions
746    explicit negative_binomial_distribution(result_type k = 1, double p = 0.5);
747    explicit negative_binomial_distribution(const param_type& parm);
748    void reset();
749
750    // generating functions
751    template<class URNG> result_type operator()(URNG& g);
752    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
753
754    // property functions
755    result_type k() const;
756    double p() const;
757
758    param_type param() const;
759    void param(const param_type& parm);
760
761    result_type min() const;
762    result_type max() const;
763
764    friend bool operator==(const negative_binomial_distribution& x,
765                           const negative_binomial_distribution& y);
766    friend bool operator!=(const negative_binomial_distribution& x,
767                           const negative_binomial_distribution& y);
768
769    template <class charT, class traits>
770    friend
771    basic_ostream<charT, traits>&
772    operator<<(basic_ostream<charT, traits>& os,
773               const negative_binomial_distribution& x);
774
775    template <class charT, class traits>
776    friend
777    basic_istream<charT, traits>&
778    operator>>(basic_istream<charT, traits>& is,
779               negative_binomial_distribution& x);
780};
781
782template<class IntType = int>
783class poisson_distribution
784{
785public:
786    // types
787    typedef IntType result_type;
788
789    class param_type
790    {
791    public:
792        typedef poisson_distribution distribution_type;
793
794        explicit param_type(double mean = 1.0);
795
796        double mean() const;
797
798        friend bool operator==(const param_type& x, const param_type& y);
799        friend bool operator!=(const param_type& x, const param_type& y);
800    };
801
802    // constructors and reset functions
803    explicit poisson_distribution(double mean = 1.0);
804    explicit poisson_distribution(const param_type& parm);
805    void reset();
806
807    // generating functions
808    template<class URNG> result_type operator()(URNG& g);
809    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
810
811    // property functions
812    double mean() const;
813
814    param_type param() const;
815    void param(const param_type& parm);
816
817    result_type min() const;
818    result_type max() const;
819
820    friend bool operator==(const poisson_distribution& x,
821                           const poisson_distribution& y);
822    friend bool operator!=(const poisson_distribution& x,
823                           const poisson_distribution& y);
824
825    template <class charT, class traits>
826    friend
827    basic_ostream<charT, traits>&
828    operator<<(basic_ostream<charT, traits>& os,
829               const poisson_distribution& x);
830
831    template <class charT, class traits>
832    friend
833    basic_istream<charT, traits>&
834    operator>>(basic_istream<charT, traits>& is,
835               poisson_distribution& x);
836};
837
838template<class RealType = double>
839class exponential_distribution
840{
841public:
842    // types
843    typedef RealType result_type;
844
845    class param_type
846    {
847    public:
848        typedef exponential_distribution distribution_type;
849
850        explicit param_type(result_type lambda = 1.0);
851
852        result_type lambda() const;
853
854        friend bool operator==(const param_type& x, const param_type& y);
855        friend bool operator!=(const param_type& x, const param_type& y);
856    };
857
858    // constructors and reset functions
859    explicit exponential_distribution(result_type lambda = 1.0);
860    explicit exponential_distribution(const param_type& parm);
861    void reset();
862
863    // generating functions
864    template<class URNG> result_type operator()(URNG& g);
865    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
866
867    // property functions
868    result_type lambda() const;
869
870    param_type param() const;
871    void param(const param_type& parm);
872
873    result_type min() const;
874    result_type max() const;
875
876    friend bool operator==(const exponential_distribution& x,
877                           const exponential_distribution& y);
878    friend bool operator!=(const exponential_distribution& x,
879                           const exponential_distribution& y);
880
881    template <class charT, class traits>
882    friend
883    basic_ostream<charT, traits>&
884    operator<<(basic_ostream<charT, traits>& os,
885               const exponential_distribution& x);
886
887    template <class charT, class traits>
888    friend
889    basic_istream<charT, traits>&
890    operator>>(basic_istream<charT, traits>& is,
891               exponential_distribution& x);
892};
893
894template<class RealType = double>
895class gamma_distribution
896{
897public:
898    // types
899    typedef RealType result_type;
900
901    class param_type
902    {
903    public:
904        typedef gamma_distribution distribution_type;
905
906        explicit param_type(result_type alpha = 1, result_type beta = 1);
907
908        result_type alpha() const;
909        result_type beta() const;
910
911        friend bool operator==(const param_type& x, const param_type& y);
912        friend bool operator!=(const param_type& x, const param_type& y);
913    };
914
915    // constructors and reset functions
916    explicit gamma_distribution(result_type alpha = 1, result_type beta = 1);
917    explicit gamma_distribution(const param_type& parm);
918    void reset();
919
920    // generating functions
921    template<class URNG> result_type operator()(URNG& g);
922    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
923
924    // property functions
925    result_type alpha() const;
926    result_type beta() const;
927
928    param_type param() const;
929    void param(const param_type& parm);
930
931    result_type min() const;
932    result_type max() const;
933
934    friend bool operator==(const gamma_distribution& x,
935                           const gamma_distribution& y);
936    friend bool operator!=(const gamma_distribution& x,
937                           const gamma_distribution& y);
938
939    template <class charT, class traits>
940    friend
941    basic_ostream<charT, traits>&
942    operator<<(basic_ostream<charT, traits>& os,
943               const gamma_distribution& x);
944
945    template <class charT, class traits>
946    friend
947    basic_istream<charT, traits>&
948    operator>>(basic_istream<charT, traits>& is,
949               gamma_distribution& x);
950};
951
952template<class RealType = double>
953class weibull_distribution
954{
955public:
956    // types
957    typedef RealType result_type;
958
959    class param_type
960    {
961    public:
962        typedef weibull_distribution distribution_type;
963
964        explicit param_type(result_type alpha = 1, result_type beta = 1);
965
966        result_type a() const;
967        result_type b() const;
968
969        friend bool operator==(const param_type& x, const param_type& y);
970        friend bool operator!=(const param_type& x, const param_type& y);
971    };
972
973    // constructor and reset functions
974    explicit weibull_distribution(result_type a = 1, result_type b = 1);
975    explicit weibull_distribution(const param_type& parm);
976    void reset();
977
978    // generating functions
979    template<class URNG> result_type operator()(URNG& g);
980    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
981
982    // property functions
983    result_type a() const;
984    result_type b() const;
985
986    param_type param() const;
987    void param(const param_type& parm);
988
989    result_type min() const;
990    result_type max() const;
991
992    friend bool operator==(const weibull_distribution& x,
993                           const weibull_distribution& y);
994    friend bool operator!=(const weibull_distribution& x,
995                           const weibull_distribution& y);
996
997    template <class charT, class traits>
998    friend
999    basic_ostream<charT, traits>&
1000    operator<<(basic_ostream<charT, traits>& os,
1001               const weibull_distribution& x);
1002
1003    template <class charT, class traits>
1004    friend
1005    basic_istream<charT, traits>&
1006    operator>>(basic_istream<charT, traits>& is,
1007               weibull_distribution& x);
1008};
1009
1010template<class RealType = double>
1011class extreme_value_distribution
1012{
1013public:
1014    // types
1015    typedef RealType result_type;
1016
1017    class param_type
1018    {
1019    public:
1020        typedef extreme_value_distribution distribution_type;
1021
1022        explicit param_type(result_type a = 0, result_type b = 1);
1023
1024        result_type a() const;
1025        result_type b() const;
1026
1027        friend bool operator==(const param_type& x, const param_type& y);
1028        friend bool operator!=(const param_type& x, const param_type& y);
1029    };
1030
1031    // constructor and reset functions
1032    explicit extreme_value_distribution(result_type a = 0, result_type b = 1);
1033    explicit extreme_value_distribution(const param_type& parm);
1034    void reset();
1035
1036    // generating functions
1037    template<class URNG> result_type operator()(URNG& g);
1038    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1039
1040    // property functions
1041    result_type a() const;
1042    result_type b() const;
1043
1044    param_type param() const;
1045    void param(const param_type& parm);
1046
1047    result_type min() const;
1048    result_type max() const;
1049
1050    friend bool operator==(const extreme_value_distribution& x,
1051                           const extreme_value_distribution& y);
1052    friend bool operator!=(const extreme_value_distribution& x,
1053                           const extreme_value_distribution& y);
1054
1055    template <class charT, class traits>
1056    friend
1057    basic_ostream<charT, traits>&
1058    operator<<(basic_ostream<charT, traits>& os,
1059               const extreme_value_distribution& x);
1060
1061    template <class charT, class traits>
1062    friend
1063    basic_istream<charT, traits>&
1064    operator>>(basic_istream<charT, traits>& is,
1065               extreme_value_distribution& x);
1066};
1067
1068template<class RealType = double>
1069class normal_distribution
1070{
1071public:
1072    // types
1073    typedef RealType result_type;
1074
1075    class param_type
1076    {
1077    public:
1078        typedef normal_distribution distribution_type;
1079
1080        explicit param_type(result_type mean = 0, result_type stddev = 1);
1081
1082        result_type mean() const;
1083        result_type stddev() const;
1084
1085        friend bool operator==(const param_type& x, const param_type& y);
1086        friend bool operator!=(const param_type& x, const param_type& y);
1087    };
1088
1089    // constructors and reset functions
1090    explicit normal_distribution(result_type mean = 0, result_type stddev = 1);
1091    explicit normal_distribution(const param_type& parm);
1092    void reset();
1093
1094    // generating functions
1095    template<class URNG> result_type operator()(URNG& g);
1096    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1097
1098    // property functions
1099    result_type mean() const;
1100    result_type stddev() const;
1101
1102    param_type param() const;
1103    void param(const param_type& parm);
1104
1105    result_type min() const;
1106    result_type max() const;
1107
1108    friend bool operator==(const normal_distribution& x,
1109                           const normal_distribution& y);
1110    friend bool operator!=(const normal_distribution& x,
1111                           const normal_distribution& y);
1112
1113    template <class charT, class traits>
1114    friend
1115    basic_ostream<charT, traits>&
1116    operator<<(basic_ostream<charT, traits>& os,
1117               const normal_distribution& x);
1118
1119    template <class charT, class traits>
1120    friend
1121    basic_istream<charT, traits>&
1122    operator>>(basic_istream<charT, traits>& is,
1123               normal_distribution& x);
1124};
1125
1126template<class RealType = double>
1127class lognormal_distribution
1128{
1129public:
1130    // types
1131    typedef RealType result_type;
1132
1133    class param_type
1134    {
1135    public:
1136        typedef lognormal_distribution distribution_type;
1137
1138        explicit param_type(result_type m = 0, result_type s = 1);
1139
1140        result_type m() const;
1141        result_type s() const;
1142
1143        friend bool operator==(const param_type& x, const param_type& y);
1144        friend bool operator!=(const param_type& x, const param_type& y);
1145    };
1146
1147    // constructor and reset functions
1148    explicit lognormal_distribution(result_type m = 0, result_type s = 1);
1149    explicit lognormal_distribution(const param_type& parm);
1150    void reset();
1151
1152    // generating functions
1153    template<class URNG> result_type operator()(URNG& g);
1154    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1155
1156    // property functions
1157    result_type m() const;
1158    result_type s() const;
1159
1160    param_type param() const;
1161    void param(const param_type& parm);
1162
1163    result_type min() const;
1164    result_type max() const;
1165
1166    friend bool operator==(const lognormal_distribution& x,
1167                           const lognormal_distribution& y);
1168    friend bool operator!=(const lognormal_distribution& x,
1169                           const lognormal_distribution& y);
1170
1171    template <class charT, class traits>
1172    friend
1173    basic_ostream<charT, traits>&
1174    operator<<(basic_ostream<charT, traits>& os,
1175               const lognormal_distribution& x);
1176
1177    template <class charT, class traits>
1178    friend
1179    basic_istream<charT, traits>&
1180    operator>>(basic_istream<charT, traits>& is,
1181               lognormal_distribution& x);
1182};
1183
1184template<class RealType = double>
1185class chi_squared_distribution
1186{
1187public:
1188    // types
1189    typedef RealType result_type;
1190
1191    class param_type
1192    {
1193    public:
1194        typedef chi_squared_distribution distribution_type;
1195
1196        explicit param_type(result_type n = 1);
1197
1198        result_type n() const;
1199
1200        friend bool operator==(const param_type& x, const param_type& y);
1201        friend bool operator!=(const param_type& x, const param_type& y);
1202    };
1203
1204    // constructor and reset functions
1205    explicit chi_squared_distribution(result_type n = 1);
1206    explicit chi_squared_distribution(const param_type& parm);
1207    void reset();
1208
1209    // generating functions
1210    template<class URNG> result_type operator()(URNG& g);
1211    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1212
1213    // property functions
1214    result_type n() const;
1215
1216    param_type param() const;
1217    void param(const param_type& parm);
1218
1219    result_type min() const;
1220    result_type max() const;
1221
1222    friend bool operator==(const chi_squared_distribution& x,
1223                           const chi_squared_distribution& y);
1224    friend bool operator!=(const chi_squared_distribution& x,
1225                           const chi_squared_distribution& y);
1226
1227    template <class charT, class traits>
1228    friend
1229    basic_ostream<charT, traits>&
1230    operator<<(basic_ostream<charT, traits>& os,
1231               const chi_squared_distribution& x);
1232
1233    template <class charT, class traits>
1234    friend
1235    basic_istream<charT, traits>&
1236    operator>>(basic_istream<charT, traits>& is,
1237               chi_squared_distribution& x);
1238};
1239
1240template<class RealType = double>
1241class cauchy_distribution
1242{
1243public:
1244    // types
1245    typedef RealType result_type;
1246
1247    class param_type
1248    {
1249    public:
1250        typedef cauchy_distribution distribution_type;
1251
1252        explicit param_type(result_type a = 0, result_type b = 1);
1253
1254        result_type a() const;
1255        result_type b() const;
1256
1257        friend bool operator==(const param_type& x, const param_type& y);
1258        friend bool operator!=(const param_type& x, const param_type& y);
1259    };
1260
1261    // constructor and reset functions
1262    explicit cauchy_distribution(result_type a = 0, result_type b = 1);
1263    explicit cauchy_distribution(const param_type& parm);
1264    void reset();
1265
1266    // generating functions
1267    template<class URNG> result_type operator()(URNG& g);
1268    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1269
1270    // property functions
1271    result_type a() const;
1272    result_type b() const;
1273
1274    param_type param() const;
1275    void param(const param_type& parm);
1276
1277    result_type min() const;
1278    result_type max() const;
1279
1280    friend bool operator==(const cauchy_distribution& x,
1281                           const cauchy_distribution& y);
1282    friend bool operator!=(const cauchy_distribution& x,
1283                           const cauchy_distribution& y);
1284
1285    template <class charT, class traits>
1286    friend
1287    basic_ostream<charT, traits>&
1288    operator<<(basic_ostream<charT, traits>& os,
1289               const cauchy_distribution& x);
1290
1291    template <class charT, class traits>
1292    friend
1293    basic_istream<charT, traits>&
1294    operator>>(basic_istream<charT, traits>& is,
1295               cauchy_distribution& x);
1296};
1297
1298template<class RealType = double>
1299class fisher_f_distribution
1300{
1301public:
1302    // types
1303    typedef RealType result_type;
1304
1305    class param_type
1306    {
1307    public:
1308        typedef fisher_f_distribution distribution_type;
1309
1310        explicit param_type(result_type m = 1, result_type n = 1);
1311
1312        result_type m() const;
1313        result_type n() const;
1314
1315        friend bool operator==(const param_type& x, const param_type& y);
1316        friend bool operator!=(const param_type& x, const param_type& y);
1317    };
1318
1319    // constructor and reset functions
1320    explicit fisher_f_distribution(result_type m = 1, result_type n = 1);
1321    explicit fisher_f_distribution(const param_type& parm);
1322    void reset();
1323
1324    // generating functions
1325    template<class URNG> result_type operator()(URNG& g);
1326    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1327
1328    // property functions
1329    result_type m() const;
1330    result_type n() const;
1331
1332    param_type param() const;
1333    void param(const param_type& parm);
1334
1335    result_type min() const;
1336    result_type max() const;
1337
1338    friend bool operator==(const fisher_f_distribution& x,
1339                           const fisher_f_distribution& y);
1340    friend bool operator!=(const fisher_f_distribution& x,
1341                           const fisher_f_distribution& y);
1342
1343    template <class charT, class traits>
1344    friend
1345    basic_ostream<charT, traits>&
1346    operator<<(basic_ostream<charT, traits>& os,
1347               const fisher_f_distribution& x);
1348
1349    template <class charT, class traits>
1350    friend
1351    basic_istream<charT, traits>&
1352    operator>>(basic_istream<charT, traits>& is,
1353               fisher_f_distribution& x);
1354};
1355
1356template<class RealType = double>
1357class student_t_distribution
1358{
1359public:
1360    // types
1361    typedef RealType result_type;
1362
1363    class param_type
1364    {
1365    public:
1366        typedef student_t_distribution distribution_type;
1367
1368        explicit param_type(result_type n = 1);
1369
1370        result_type n() const;
1371
1372        friend bool operator==(const param_type& x, const param_type& y);
1373        friend bool operator!=(const param_type& x, const param_type& y);
1374    };
1375
1376    // constructor and reset functions
1377    explicit student_t_distribution(result_type n = 1);
1378    explicit student_t_distribution(const param_type& parm);
1379    void reset();
1380
1381    // generating functions
1382    template<class URNG> result_type operator()(URNG& g);
1383    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1384
1385    // property functions
1386    result_type n() const;
1387
1388    param_type param() const;
1389    void param(const param_type& parm);
1390
1391    result_type min() const;
1392    result_type max() const;
1393
1394    friend bool operator==(const student_t_distribution& x,
1395                           const student_t_distribution& y);
1396    friend bool operator!=(const student_t_distribution& x,
1397                           const student_t_distribution& y);
1398
1399    template <class charT, class traits>
1400    friend
1401    basic_ostream<charT, traits>&
1402    operator<<(basic_ostream<charT, traits>& os,
1403               const student_t_distribution& x);
1404
1405    template <class charT, class traits>
1406    friend
1407    basic_istream<charT, traits>&
1408    operator>>(basic_istream<charT, traits>& is,
1409               student_t_distribution& x);
1410};
1411
1412template<class IntType = int>
1413class discrete_distribution
1414{
1415public:
1416    // types
1417    typedef IntType result_type;
1418
1419    class param_type
1420    {
1421    public:
1422        typedef discrete_distribution distribution_type;
1423
1424        param_type();
1425        template<class InputIterator>
1426            param_type(InputIterator firstW, InputIterator lastW);
1427        param_type(initializer_list<double> wl);
1428        template<class UnaryOperation>
1429            param_type(size_t nw, double xmin, double xmax, UnaryOperation fw);
1430
1431        vector<double> probabilities() const;
1432
1433        friend bool operator==(const param_type& x, const param_type& y);
1434        friend bool operator!=(const param_type& x, const param_type& y);
1435    };
1436
1437    // constructor and reset functions
1438    discrete_distribution();
1439    template<class InputIterator>
1440        discrete_distribution(InputIterator firstW, InputIterator lastW);
1441    discrete_distribution(initializer_list<double> wl);
1442    template<class UnaryOperation>
1443        discrete_distribution(size_t nw, double xmin, double xmax,
1444                              UnaryOperation fw);
1445    explicit discrete_distribution(const param_type& parm);
1446    void reset();
1447
1448    // generating functions
1449    template<class URNG> result_type operator()(URNG& g);
1450    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1451
1452    // property functions
1453    vector<double> probabilities() const;
1454
1455    param_type param() const;
1456    void param(const param_type& parm);
1457
1458    result_type min() const;
1459    result_type max() const;
1460
1461    friend bool operator==(const discrete_distribution& x,
1462                           const discrete_distribution& y);
1463    friend bool operator!=(const discrete_distribution& x,
1464                           const discrete_distribution& y);
1465
1466    template <class charT, class traits>
1467    friend
1468    basic_ostream<charT, traits>&
1469    operator<<(basic_ostream<charT, traits>& os,
1470               const discrete_distribution& x);
1471
1472    template <class charT, class traits>
1473    friend
1474    basic_istream<charT, traits>&
1475    operator>>(basic_istream<charT, traits>& is,
1476               discrete_distribution& x);
1477};
1478
1479template<class RealType = double>
1480class piecewise_constant_distribution
1481{
1482    // types
1483    typedef RealType result_type;
1484
1485    class param_type
1486    {
1487    public:
1488        typedef piecewise_constant_distribution distribution_type;
1489
1490        param_type();
1491        template<class InputIteratorB, class InputIteratorW>
1492            param_type(InputIteratorB firstB, InputIteratorB lastB,
1493                       InputIteratorW firstW);
1494        template<class UnaryOperation>
1495            param_type(initializer_list<result_type> bl, UnaryOperation fw);
1496        template<class UnaryOperation>
1497            param_type(size_t nw, result_type xmin, result_type xmax,
1498                       UnaryOperation fw);
1499
1500        vector<result_type> intervals() const;
1501        vector<result_type> densities() const;
1502
1503        friend bool operator==(const param_type& x, const param_type& y);
1504        friend bool operator!=(const param_type& x, const param_type& y);
1505    };
1506
1507    // constructor and reset functions
1508    piecewise_constant_distribution();
1509    template<class InputIteratorB, class InputIteratorW>
1510        piecewise_constant_distribution(InputIteratorB firstB,
1511                                        InputIteratorB lastB,
1512                                        InputIteratorW firstW);
1513    template<class UnaryOperation>
1514        piecewise_constant_distribution(initializer_list<result_type> bl,
1515                                        UnaryOperation fw);
1516    template<class UnaryOperation>
1517        piecewise_constant_distribution(size_t nw, result_type xmin,
1518                                        result_type xmax, UnaryOperation fw);
1519    explicit piecewise_constant_distribution(const param_type& parm);
1520    void reset();
1521
1522    // generating functions
1523    template<class URNG> result_type operator()(URNG& g);
1524    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1525
1526    // property functions
1527    vector<result_type> intervals() const;
1528    vector<result_type> densities() const;
1529
1530    param_type param() const;
1531    void param(const param_type& parm);
1532
1533    result_type min() const;
1534    result_type max() const;
1535
1536    friend bool operator==(const piecewise_constant_distribution& x,
1537                           const piecewise_constant_distribution& y);
1538    friend bool operator!=(const piecewise_constant_distribution& x,
1539                           const piecewise_constant_distribution& y);
1540
1541    template <class charT, class traits>
1542    friend
1543    basic_ostream<charT, traits>&
1544    operator<<(basic_ostream<charT, traits>& os,
1545               const piecewise_constant_distribution& x);
1546
1547    template <class charT, class traits>
1548    friend
1549    basic_istream<charT, traits>&
1550    operator>>(basic_istream<charT, traits>& is,
1551               piecewise_constant_distribution& x);
1552};
1553
1554template<class RealType = double>
1555class piecewise_linear_distribution
1556{
1557    // types
1558    typedef RealType result_type;
1559
1560    class param_type
1561    {
1562    public:
1563        typedef piecewise_linear_distribution distribution_type;
1564
1565        param_type();
1566        template<class InputIteratorB, class InputIteratorW>
1567            param_type(InputIteratorB firstB, InputIteratorB lastB,
1568                       InputIteratorW firstW);
1569        template<class UnaryOperation>
1570            param_type(initializer_list<result_type> bl, UnaryOperation fw);
1571        template<class UnaryOperation>
1572            param_type(size_t nw, result_type xmin, result_type xmax,
1573                       UnaryOperation fw);
1574
1575        vector<result_type> intervals() const;
1576        vector<result_type> densities() const;
1577
1578        friend bool operator==(const param_type& x, const param_type& y);
1579        friend bool operator!=(const param_type& x, const param_type& y);
1580    };
1581
1582    // constructor and reset functions
1583    piecewise_linear_distribution();
1584    template<class InputIteratorB, class InputIteratorW>
1585        piecewise_linear_distribution(InputIteratorB firstB,
1586                                      InputIteratorB lastB,
1587                                      InputIteratorW firstW);
1588
1589    template<class UnaryOperation>
1590        piecewise_linear_distribution(initializer_list<result_type> bl,
1591                                      UnaryOperation fw);
1592
1593    template<class UnaryOperation>
1594        piecewise_linear_distribution(size_t nw, result_type xmin,
1595                                      result_type xmax, UnaryOperation fw);
1596
1597    explicit piecewise_linear_distribution(const param_type& parm);
1598    void reset();
1599
1600    // generating functions
1601    template<class URNG> result_type operator()(URNG& g);
1602    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1603
1604    // property functions
1605    vector<result_type> intervals() const;
1606    vector<result_type> densities() const;
1607
1608    param_type param() const;
1609    void param(const param_type& parm);
1610
1611    result_type min() const;
1612    result_type max() const;
1613
1614    friend bool operator==(const piecewise_linear_distribution& x,
1615                           const piecewise_linear_distribution& y);
1616    friend bool operator!=(const piecewise_linear_distribution& x,
1617                           const piecewise_linear_distribution& y);
1618
1619    template <class charT, class traits>
1620    friend
1621    basic_ostream<charT, traits>&
1622    operator<<(basic_ostream<charT, traits>& os,
1623               const piecewise_linear_distribution& x);
1624
1625    template <class charT, class traits>
1626    friend
1627    basic_istream<charT, traits>&
1628    operator>>(basic_istream<charT, traits>& is,
1629               piecewise_linear_distribution& x);
1630};
1631
1632} // std
1633*/
1634
1635#include <__config>
1636#include <cstddef>
1637#include <type_traits>
1638#include <initializer_list>
1639#include <cstdint>
1640#include <limits>
1641#include <algorithm>
1642#include <numeric>
1643#include <vector>
1644#include <string>
1645#include <istream>
1646#include <ostream>
1647#include <cmath>
1648
1649#include <__undef_min_max>
1650
1651#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
1652#pragma GCC system_header
1653#endif
1654
1655_LIBCPP_BEGIN_NAMESPACE_STD
1656
1657// __is_seed_sequence
1658
1659template <class _Sseq, class _Engine>
1660struct __is_seed_sequence
1661{
1662    static _LIBCPP_CONSTEXPR const bool value =
1663              !is_convertible<_Sseq, typename _Engine::result_type>::value &&
1664              !is_same<typename remove_cv<_Sseq>::type, _Engine>::value;
1665};
1666
1667// linear_congruential_engine
1668
1669template <unsigned long long __a, unsigned long long __c,
1670          unsigned long long __m, unsigned long long _Mp,
1671          bool _MightOverflow = (__a != 0 && __m != 0 && __m-1 > (_Mp-__c)/__a)>
1672struct __lce_ta;
1673
1674// 64
1675
1676template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
1677struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), true>
1678{
1679    typedef unsigned long long result_type;
1680    _LIBCPP_INLINE_VISIBILITY
1681    static result_type next(result_type __x)
1682    {
1683        // Schrage's algorithm
1684        const result_type __q = __m / __a;
1685        const result_type __r = __m % __a;
1686        const result_type __t0 = __a * (__x % __q);
1687        const result_type __t1 = __r * (__x / __q);
1688        __x = __t0 + (__t0 < __t1) * __m - __t1;
1689        __x += __c - (__x >= __m - __c) * __m;
1690        return __x;
1691    }
1692};
1693
1694template <unsigned long long __a, unsigned long long __m>
1695struct __lce_ta<__a, 0, __m, (unsigned long long)(~0), true>
1696{
1697    typedef unsigned long long result_type;
1698    _LIBCPP_INLINE_VISIBILITY
1699    static result_type next(result_type __x)
1700    {
1701        // Schrage's algorithm
1702        const result_type __q = __m / __a;
1703        const result_type __r = __m % __a;
1704        const result_type __t0 = __a * (__x % __q);
1705        const result_type __t1 = __r * (__x / __q);
1706        __x = __t0 + (__t0 < __t1) * __m - __t1;
1707        return __x;
1708    }
1709};
1710
1711template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
1712struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), false>
1713{
1714    typedef unsigned long long result_type;
1715    _LIBCPP_INLINE_VISIBILITY
1716    static result_type next(result_type __x)
1717    {
1718        return (__a * __x + __c) % __m;
1719    }
1720};
1721
1722template <unsigned long long __a, unsigned long long __c>
1723struct __lce_ta<__a, __c, 0, (unsigned long long)(~0), false>
1724{
1725    typedef unsigned long long result_type;
1726    _LIBCPP_INLINE_VISIBILITY
1727    static result_type next(result_type __x)
1728    {
1729        return __a * __x + __c;
1730    }
1731};
1732
1733// 32
1734
1735template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
1736struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), true>
1737{
1738    typedef unsigned result_type;
1739    _LIBCPP_INLINE_VISIBILITY
1740    static result_type next(result_type __x)
1741    {
1742        const result_type __a = static_cast<result_type>(_Ap);
1743        const result_type __c = static_cast<result_type>(_Cp);
1744        const result_type __m = static_cast<result_type>(_Mp);
1745        // Schrage's algorithm
1746        const result_type __q = __m / __a;
1747        const result_type __r = __m % __a;
1748        const result_type __t0 = __a * (__x % __q);
1749        const result_type __t1 = __r * (__x / __q);
1750        __x = __t0 + (__t0 < __t1) * __m - __t1;
1751        __x += __c - (__x >= __m - __c) * __m;
1752        return __x;
1753    }
1754};
1755
1756template <unsigned long long _Ap, unsigned long long _Mp>
1757struct __lce_ta<_Ap, 0, _Mp, unsigned(~0), true>
1758{
1759    typedef unsigned result_type;
1760    _LIBCPP_INLINE_VISIBILITY
1761    static result_type next(result_type __x)
1762    {
1763        const result_type __a = static_cast<result_type>(_Ap);
1764        const result_type __m = static_cast<result_type>(_Mp);
1765        // Schrage's algorithm
1766        const result_type __q = __m / __a;
1767        const result_type __r = __m % __a;
1768        const result_type __t0 = __a * (__x % __q);
1769        const result_type __t1 = __r * (__x / __q);
1770        __x = __t0 + (__t0 < __t1) * __m - __t1;
1771        return __x;
1772    }
1773};
1774
1775template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
1776struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), false>
1777{
1778    typedef unsigned result_type;
1779    _LIBCPP_INLINE_VISIBILITY
1780    static result_type next(result_type __x)
1781    {
1782        const result_type __a = static_cast<result_type>(_Ap);
1783        const result_type __c = static_cast<result_type>(_Cp);
1784        const result_type __m = static_cast<result_type>(_Mp);
1785        return (__a * __x + __c) % __m;
1786    }
1787};
1788
1789template <unsigned long long _Ap, unsigned long long _Cp>
1790struct __lce_ta<_Ap, _Cp, 0, unsigned(~0), false>
1791{
1792    typedef unsigned result_type;
1793    _LIBCPP_INLINE_VISIBILITY
1794    static result_type next(result_type __x)
1795    {
1796        const result_type __a = static_cast<result_type>(_Ap);
1797        const result_type __c = static_cast<result_type>(_Cp);
1798        return __a * __x + __c;
1799    }
1800};
1801
1802// 16
1803
1804template <unsigned long long __a, unsigned long long __c, unsigned long long __m, bool __b>
1805struct __lce_ta<__a, __c, __m, (unsigned short)(~0), __b>
1806{
1807    typedef unsigned short result_type;
1808    _LIBCPP_INLINE_VISIBILITY
1809    static result_type next(result_type __x)
1810    {
1811        return static_cast<result_type>(__lce_ta<__a, __c, __m, unsigned(~0)>::next(__x));
1812    }
1813};
1814
1815template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1816class linear_congruential_engine;
1817
1818template <class _CharT, class _Traits,
1819          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1820basic_ostream<_CharT, _Traits>&
1821operator<<(basic_ostream<_CharT, _Traits>& __os,
1822           const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
1823
1824template <class _CharT, class _Traits,
1825          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1826basic_istream<_CharT, _Traits>&
1827operator>>(basic_istream<_CharT, _Traits>& __is,
1828           linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
1829
1830template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1831class _LIBCPP_VISIBLE linear_congruential_engine
1832{
1833public:
1834    // types
1835    typedef _UIntType result_type;
1836
1837private:
1838    result_type __x_;
1839
1840    static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0);
1841
1842    static_assert(__m == 0 || __a < __m, "linear_congruential_engine invalid parameters");
1843    static_assert(__m == 0 || __c < __m, "linear_congruential_engine invalid parameters");
1844public:
1845    static _LIBCPP_CONSTEXPR const result_type _Min = __c == 0u ? 1u: 0u;
1846    static _LIBCPP_CONSTEXPR const result_type _Max = __m - 1u;
1847    static_assert(_Min < _Max,           "linear_congruential_engine invalid parameters");
1848
1849    // engine characteristics
1850    static _LIBCPP_CONSTEXPR const result_type multiplier = __a;
1851    static _LIBCPP_CONSTEXPR const result_type increment = __c;
1852    static _LIBCPP_CONSTEXPR const result_type modulus = __m;
1853    _LIBCPP_INLINE_VISIBILITY
1854    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
1855    _LIBCPP_INLINE_VISIBILITY
1856    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
1857    static _LIBCPP_CONSTEXPR const result_type default_seed = 1u;
1858
1859    // constructors and seeding functions
1860    _LIBCPP_INLINE_VISIBILITY
1861    explicit linear_congruential_engine(result_type __s = default_seed)
1862        {seed(__s);}
1863    template<class _Sseq>
1864        _LIBCPP_INLINE_VISIBILITY
1865        explicit linear_congruential_engine(_Sseq& __q,
1866        typename enable_if<__is_seed_sequence<_Sseq, linear_congruential_engine>::value>::type* = 0)
1867        {seed(__q);}
1868    _LIBCPP_INLINE_VISIBILITY
1869    void seed(result_type __s = default_seed)
1870        {seed(integral_constant<bool, __m == 0>(),
1871              integral_constant<bool, __c == 0>(), __s);}
1872    template<class _Sseq>
1873        _LIBCPP_INLINE_VISIBILITY
1874        typename enable_if
1875        <
1876            __is_seed_sequence<_Sseq, linear_congruential_engine>::value,
1877            void
1878        >::type
1879        seed(_Sseq& __q)
1880            {__seed(__q, integral_constant<unsigned,
1881                1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32
1882                             :  (__m-1) / 0x100000000ull)>());}
1883
1884    // generating functions
1885    _LIBCPP_INLINE_VISIBILITY
1886    result_type operator()()
1887        {return __x_ = static_cast<result_type>(__lce_ta<__a, __c, __m, _Mp>::next(__x_));}
1888    _LIBCPP_INLINE_VISIBILITY
1889    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
1890
1891    friend _LIBCPP_INLINE_VISIBILITY
1892    bool operator==(const linear_congruential_engine& __x,
1893                    const linear_congruential_engine& __y)
1894        {return __x.__x_ == __y.__x_;}
1895    friend _LIBCPP_INLINE_VISIBILITY
1896    bool operator!=(const linear_congruential_engine& __x,
1897                    const linear_congruential_engine& __y)
1898        {return !(__x == __y);}
1899
1900private:
1901
1902    _LIBCPP_INLINE_VISIBILITY
1903    void seed(true_type, true_type, result_type __s) {__x_ = __s == 0 ? 1 : __s;}
1904    _LIBCPP_INLINE_VISIBILITY
1905    void seed(true_type, false_type, result_type __s) {__x_ = __s;}
1906    _LIBCPP_INLINE_VISIBILITY
1907    void seed(false_type, true_type, result_type __s) {__x_ = __s % __m == 0 ?
1908                                                                 1 : __s % __m;}
1909    _LIBCPP_INLINE_VISIBILITY
1910    void seed(false_type, false_type, result_type __s) {__x_ = __s % __m;}
1911
1912    template<class _Sseq>
1913        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
1914    template<class _Sseq>
1915        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
1916
1917    template <class _CharT, class _Traits,
1918              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1919    friend
1920    basic_ostream<_CharT, _Traits>&
1921    operator<<(basic_ostream<_CharT, _Traits>& __os,
1922               const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
1923
1924    template <class _CharT, class _Traits,
1925              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1926    friend
1927    basic_istream<_CharT, _Traits>&
1928    operator>>(basic_istream<_CharT, _Traits>& __is,
1929               linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
1930};
1931
1932template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1933template<class _Sseq>
1934void
1935linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
1936                                                 integral_constant<unsigned, 1>)
1937{
1938    const unsigned __k = 1;
1939    uint32_t __ar[__k+3];
1940    __q.generate(__ar, __ar + __k + 3);
1941    result_type __s = static_cast<result_type>(__ar[3] % __m);
1942    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
1943}
1944
1945template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1946template<class _Sseq>
1947void
1948linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
1949                                                 integral_constant<unsigned, 2>)
1950{
1951    const unsigned __k = 2;
1952    uint32_t __ar[__k+3];
1953    __q.generate(__ar, __ar + __k + 3);
1954    result_type __s = static_cast<result_type>((__ar[3] +
1955                                                (uint64_t)__ar[4] << 32) % __m);
1956    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
1957}
1958
1959template <class _CharT, class _Traits>
1960class __save_flags
1961{
1962    typedef basic_ios<_CharT, _Traits> __stream_type;
1963    typedef typename __stream_type::fmtflags fmtflags;
1964
1965    __stream_type& __stream_;
1966    fmtflags       __fmtflags_;
1967    _CharT         __fill_;
1968
1969    __save_flags(const __save_flags&);
1970    __save_flags& operator=(const __save_flags&);
1971public:
1972    _LIBCPP_INLINE_VISIBILITY
1973    explicit __save_flags(__stream_type& __stream)
1974        : __stream_(__stream),
1975          __fmtflags_(__stream.flags()),
1976          __fill_(__stream.fill())
1977        {}
1978    _LIBCPP_INLINE_VISIBILITY
1979    ~__save_flags()
1980    {
1981        __stream_.flags(__fmtflags_);
1982        __stream_.fill(__fill_);
1983    }
1984};
1985
1986template <class _CharT, class _Traits,
1987          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1988inline _LIBCPP_INLINE_VISIBILITY
1989basic_ostream<_CharT, _Traits>&
1990operator<<(basic_ostream<_CharT, _Traits>& __os,
1991           const linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
1992{
1993    __save_flags<_CharT, _Traits> _(__os);
1994    __os.flags(ios_base::dec | ios_base::left);
1995    __os.fill(__os.widen(' '));
1996    return __os << __x.__x_;
1997}
1998
1999template <class _CharT, class _Traits,
2000          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
2001basic_istream<_CharT, _Traits>&
2002operator>>(basic_istream<_CharT, _Traits>& __is,
2003           linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
2004{
2005    __save_flags<_CharT, _Traits> _(__is);
2006    __is.flags(ios_base::dec | ios_base::skipws);
2007    _UIntType __t;
2008    __is >> __t;
2009    if (!__is.fail())
2010        __x.__x_ = __t;
2011    return __is;
2012}
2013
2014typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
2015                                                                   minstd_rand0;
2016typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
2017                                                                    minstd_rand;
2018typedef minstd_rand                                       default_random_engine;
2019// mersenne_twister_engine
2020
2021template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2022          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2023          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2024class mersenne_twister_engine;
2025
2026template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2027          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2028          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2029bool
2030operator==(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2031                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2032           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2033                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2034
2035template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2036          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2037          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2038bool
2039operator!=(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2040                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2041           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2042                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2043
2044template <class _CharT, class _Traits,
2045          class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2046          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2047          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2048basic_ostream<_CharT, _Traits>&
2049operator<<(basic_ostream<_CharT, _Traits>& __os,
2050           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2051                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2052
2053template <class _CharT, class _Traits,
2054          class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2055          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2056          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2057basic_istream<_CharT, _Traits>&
2058operator>>(basic_istream<_CharT, _Traits>& __is,
2059           mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2060                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2061
2062template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2063          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2064          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2065class _LIBCPP_VISIBLE mersenne_twister_engine
2066{
2067public:
2068    // types
2069    typedef _UIntType result_type;
2070
2071private:
2072    result_type __x_[__n];
2073    size_t      __i_;
2074
2075    static_assert(  0 <  __m, "mersenne_twister_engine invalid parameters");
2076    static_assert(__m <= __n, "mersenne_twister_engine invalid parameters");
2077    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
2078    static_assert(__w <= _Dt, "mersenne_twister_engine invalid parameters");
2079    static_assert(  2 <= __w, "mersenne_twister_engine invalid parameters");
2080    static_assert(__r <= __w, "mersenne_twister_engine invalid parameters");
2081    static_assert(__u <= __w, "mersenne_twister_engine invalid parameters");
2082    static_assert(__s <= __w, "mersenne_twister_engine invalid parameters");
2083    static_assert(__t <= __w, "mersenne_twister_engine invalid parameters");
2084    static_assert(__l <= __w, "mersenne_twister_engine invalid parameters");
2085public:
2086    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
2087    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
2088                                                      (result_type(1) << __w) - result_type(1);
2089    static_assert(_Min < _Max, "mersenne_twister_engine invalid parameters");
2090    static_assert(__a <= _Max, "mersenne_twister_engine invalid parameters");
2091    static_assert(__b <= _Max, "mersenne_twister_engine invalid parameters");
2092    static_assert(__c <= _Max, "mersenne_twister_engine invalid parameters");
2093    static_assert(__d <= _Max, "mersenne_twister_engine invalid parameters");
2094    static_assert(__f <= _Max, "mersenne_twister_engine invalid parameters");
2095
2096    // engine characteristics
2097    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
2098    static _LIBCPP_CONSTEXPR const size_t state_size = __n;
2099    static _LIBCPP_CONSTEXPR const size_t shift_size = __m;
2100    static _LIBCPP_CONSTEXPR const size_t mask_bits = __r;
2101    static _LIBCPP_CONSTEXPR const result_type xor_mask = __a;
2102    static _LIBCPP_CONSTEXPR const size_t tempering_u = __u;
2103    static _LIBCPP_CONSTEXPR const result_type tempering_d = __d;
2104    static _LIBCPP_CONSTEXPR const size_t tempering_s = __s;
2105    static _LIBCPP_CONSTEXPR const result_type tempering_b = __b;
2106    static _LIBCPP_CONSTEXPR const size_t tempering_t = __t;
2107    static _LIBCPP_CONSTEXPR const result_type tempering_c = __c;
2108    static _LIBCPP_CONSTEXPR const size_t tempering_l = __l;
2109    static _LIBCPP_CONSTEXPR const result_type initialization_multiplier = __f;
2110    _LIBCPP_INLINE_VISIBILITY
2111    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
2112    _LIBCPP_INLINE_VISIBILITY
2113    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
2114    static _LIBCPP_CONSTEXPR const result_type default_seed = 5489u;
2115
2116    // constructors and seeding functions
2117    _LIBCPP_INLINE_VISIBILITY
2118    explicit mersenne_twister_engine(result_type __sd = default_seed)
2119        {seed(__sd);}
2120    template<class _Sseq>
2121        _LIBCPP_INLINE_VISIBILITY
2122        explicit mersenne_twister_engine(_Sseq& __q,
2123        typename enable_if<__is_seed_sequence<_Sseq, mersenne_twister_engine>::value>::type* = 0)
2124        {seed(__q);}
2125    void seed(result_type __sd = default_seed);
2126    template<class _Sseq>
2127        _LIBCPP_INLINE_VISIBILITY
2128        typename enable_if
2129        <
2130            __is_seed_sequence<_Sseq, mersenne_twister_engine>::value,
2131            void
2132        >::type
2133        seed(_Sseq& __q)
2134            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2135
2136    // generating functions
2137    result_type operator()();
2138    _LIBCPP_INLINE_VISIBILITY
2139    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2140
2141    template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2142              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2143              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2144    friend
2145    bool
2146    operator==(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2147                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2148               const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2149                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2150
2151    template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2152              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2153              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2154    friend
2155    bool
2156    operator!=(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2157                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2158               const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2159                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2160
2161    template <class _CharT, class _Traits,
2162              class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2163              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2164              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2165    friend
2166    basic_ostream<_CharT, _Traits>&
2167    operator<<(basic_ostream<_CharT, _Traits>& __os,
2168               const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2169                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2170
2171    template <class _CharT, class _Traits,
2172              class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2173              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2174              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2175    friend
2176    basic_istream<_CharT, _Traits>&
2177    operator>>(basic_istream<_CharT, _Traits>& __is,
2178               mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2179                                       _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2180private:
2181
2182    template<class _Sseq>
2183        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
2184    template<class _Sseq>
2185        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
2186
2187    template <size_t __count>
2188        _LIBCPP_INLINE_VISIBILITY
2189        static
2190        typename enable_if
2191        <
2192            __count < __w,
2193            result_type
2194        >::type
2195        __lshift(result_type __x) {return (__x << __count) & _Max;}
2196
2197    template <size_t __count>
2198        _LIBCPP_INLINE_VISIBILITY
2199        static
2200        typename enable_if
2201        <
2202            (__count >= __w),
2203            result_type
2204        >::type
2205        __lshift(result_type) {return result_type(0);}
2206
2207    template <size_t __count>
2208        _LIBCPP_INLINE_VISIBILITY
2209        static
2210        typename enable_if
2211        <
2212            __count < _Dt,
2213            result_type
2214        >::type
2215        __rshift(result_type __x) {return __x >> __count;}
2216
2217    template <size_t __count>
2218        _LIBCPP_INLINE_VISIBILITY
2219        static
2220        typename enable_if
2221        <
2222            (__count >= _Dt),
2223            result_type
2224        >::type
2225        __rshift(result_type) {return result_type(0);}
2226};
2227
2228template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2229          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2230          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2231void
2232mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2233    __t, __c, __l, __f>::seed(result_type __sd)
2234{   // __w >= 2
2235    __x_[0] = __sd & _Max;
2236    for (size_t __i = 1; __i < __n; ++__i)
2237        __x_[__i] = (__f * (__x_[__i-1] ^ __rshift<__w - 2>(__x_[__i-1])) + __i) & _Max;
2238    __i_ = 0;
2239}
2240
2241template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2242          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2243          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2244template<class _Sseq>
2245void
2246mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2247    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 1>)
2248{
2249    const unsigned __k = 1;
2250    uint32_t __ar[__n * __k];
2251    __q.generate(__ar, __ar + __n * __k);
2252    for (size_t __i = 0; __i < __n; ++__i)
2253        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
2254    const result_type __mask = __r == _Dt ? result_type(~0) :
2255                                       (result_type(1) << __r) - result_type(1);
2256    __i_ = 0;
2257    if ((__x_[0] & ~__mask) == 0)
2258    {
2259        for (size_t __i = 1; __i < __n; ++__i)
2260            if (__x_[__i] != 0)
2261                return;
2262        __x_[0] = _Max;
2263    }
2264}
2265
2266template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2267          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2268          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2269template<class _Sseq>
2270void
2271mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2272    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 2>)
2273{
2274    const unsigned __k = 2;
2275    uint32_t __ar[__n * __k];
2276    __q.generate(__ar, __ar + __n * __k);
2277    for (size_t __i = 0; __i < __n; ++__i)
2278        __x_[__i] = static_cast<result_type>(
2279            (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
2280    const result_type __mask = __r == _Dt ? result_type(~0) :
2281                                       (result_type(1) << __r) - result_type(1);
2282    __i_ = 0;
2283    if ((__x_[0] & ~__mask) == 0)
2284    {
2285        for (size_t __i = 1; __i < __n; ++__i)
2286            if (__x_[__i] != 0)
2287                return;
2288        __x_[0] = _Max;
2289    }
2290}
2291
2292template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2293          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2294          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2295_UIntType
2296mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2297    __t, __c, __l, __f>::operator()()
2298{
2299    const size_t __j = (__i_ + 1) % __n;
2300    const result_type __mask = __r == _Dt ? result_type(~0) :
2301                                       (result_type(1) << __r) - result_type(1);
2302    const result_type _Yp = (__x_[__i_] & ~__mask) | (__x_[__j] & __mask);
2303    const size_t __k = (__i_ + __m) % __n;
2304    __x_[__i_] = __x_[__k] ^ __rshift<1>(_Yp) ^ (__a * (_Yp & 1));
2305    result_type __z = __x_[__i_] ^ (__rshift<__u>(__x_[__i_]) & __d);
2306    __i_ = __j;
2307    __z ^= __lshift<__s>(__z) & __b;
2308    __z ^= __lshift<__t>(__z) & __c;
2309    return __z ^ __rshift<__l>(__z);
2310}
2311
2312template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2313          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2314          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2315bool
2316operator==(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2317                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2318           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2319                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
2320{
2321    if (__x.__i_ == __y.__i_)
2322        return _VSTD::equal(__x.__x_, __x.__x_ + _Np, __y.__x_);
2323    if (__x.__i_ == 0 || __y.__i_ == 0)
2324    {
2325        size_t __j = _VSTD::min(_Np - __x.__i_, _Np - __y.__i_);
2326        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
2327                         __y.__x_ + __y.__i_))
2328            return false;
2329        if (__x.__i_ == 0)
2330            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Np, __y.__x_);
2331        return _VSTD::equal(__x.__x_, __x.__x_ + (_Np - __j), __y.__x_ + __j);
2332    }
2333    if (__x.__i_ < __y.__i_)
2334    {
2335        size_t __j = _Np - __y.__i_;
2336        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
2337                         __y.__x_ + __y.__i_))
2338            return false;
2339        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Np,
2340                         __y.__x_))
2341            return false;
2342        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
2343                           __y.__x_ + (_Np - (__x.__i_ + __j)));
2344    }
2345    size_t __j = _Np - __x.__i_;
2346    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
2347                     __x.__x_ + __x.__i_))
2348        return false;
2349    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Np,
2350                     __x.__x_))
2351        return false;
2352    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
2353                       __x.__x_ + (_Np - (__y.__i_ + __j)));
2354}
2355
2356template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2357          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2358          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2359inline _LIBCPP_INLINE_VISIBILITY
2360bool
2361operator!=(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2362                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2363           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2364                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
2365{
2366    return !(__x == __y);
2367}
2368
2369template <class _CharT, class _Traits,
2370          class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2371          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2372          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2373basic_ostream<_CharT, _Traits>&
2374operator<<(basic_ostream<_CharT, _Traits>& __os,
2375           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2376                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
2377{
2378    __save_flags<_CharT, _Traits> _(__os);
2379    __os.flags(ios_base::dec | ios_base::left);
2380    _CharT __sp = __os.widen(' ');
2381    __os.fill(__sp);
2382    __os << __x.__x_[__x.__i_];
2383    for (size_t __j = __x.__i_ + 1; __j < _Np; ++__j)
2384        __os << __sp << __x.__x_[__j];
2385    for (size_t __j = 0; __j < __x.__i_; ++__j)
2386        __os << __sp << __x.__x_[__j];
2387    return __os;
2388}
2389
2390template <class _CharT, class _Traits,
2391          class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2392          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2393          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2394basic_istream<_CharT, _Traits>&
2395operator>>(basic_istream<_CharT, _Traits>& __is,
2396           mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2397                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
2398{
2399    __save_flags<_CharT, _Traits> _(__is);
2400    __is.flags(ios_base::dec | ios_base::skipws);
2401    _UI __t[_Np];
2402    for (size_t __i = 0; __i < _Np; ++__i)
2403        __is >> __t[__i];
2404    if (!__is.fail())
2405    {
2406        for (size_t __i = 0; __i < _Np; ++__i)
2407            __x.__x_[__i] = __t[__i];
2408        __x.__i_ = 0;
2409    }
2410    return __is;
2411}
2412
2413typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
2414                                0x9908b0df, 11, 0xffffffff,
2415                                7,  0x9d2c5680,
2416                                15, 0xefc60000,
2417                                18, 1812433253>                         mt19937;
2418typedef mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
2419                                0xb5026f5aa96619e9ULL, 29, 0x5555555555555555ULL,
2420                                17, 0x71d67fffeda60000ULL,
2421                                37, 0xfff7eee000000000ULL,
2422                                43, 6364136223846793005ULL>          mt19937_64;
2423
2424// subtract_with_carry_engine
2425
2426template<class _UIntType, size_t __w, size_t __s, size_t __r>
2427class subtract_with_carry_engine;
2428
2429template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2430bool
2431operator==(
2432    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2433    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2434
2435template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2436bool
2437operator!=(
2438    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2439    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2440
2441template <class _CharT, class _Traits,
2442          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2443basic_ostream<_CharT, _Traits>&
2444operator<<(basic_ostream<_CharT, _Traits>& __os,
2445           const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2446
2447template <class _CharT, class _Traits,
2448          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2449basic_istream<_CharT, _Traits>&
2450operator>>(basic_istream<_CharT, _Traits>& __is,
2451           subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2452
2453template<class _UIntType, size_t __w, size_t __s, size_t __r>
2454class _LIBCPP_VISIBLE subtract_with_carry_engine
2455{
2456public:
2457    // types
2458    typedef _UIntType result_type;
2459
2460private:
2461    result_type __x_[__r];
2462    result_type  __c_;
2463    size_t      __i_;
2464
2465    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
2466    static_assert(  0 <  __w, "subtract_with_carry_engine invalid parameters");
2467    static_assert(__w <= _Dt, "subtract_with_carry_engine invalid parameters");
2468    static_assert(  0 <  __s, "subtract_with_carry_engine invalid parameters");
2469    static_assert(__s <  __r, "subtract_with_carry_engine invalid parameters");
2470public:
2471    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
2472    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
2473                                                      (result_type(1) << __w) - result_type(1);
2474    static_assert(_Min < _Max, "subtract_with_carry_engine invalid parameters");
2475
2476    // engine characteristics
2477    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
2478    static _LIBCPP_CONSTEXPR const size_t short_lag = __s;
2479    static _LIBCPP_CONSTEXPR const size_t long_lag = __r;
2480    _LIBCPP_INLINE_VISIBILITY
2481    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
2482    _LIBCPP_INLINE_VISIBILITY
2483    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
2484    static _LIBCPP_CONSTEXPR const result_type default_seed = 19780503u;
2485
2486    // constructors and seeding functions
2487    _LIBCPP_INLINE_VISIBILITY
2488    explicit subtract_with_carry_engine(result_type __sd = default_seed)
2489        {seed(__sd);}
2490    template<class _Sseq>
2491        _LIBCPP_INLINE_VISIBILITY
2492        explicit subtract_with_carry_engine(_Sseq& __q,
2493        typename enable_if<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value>::type* = 0)
2494        {seed(__q);}
2495    _LIBCPP_INLINE_VISIBILITY
2496    void seed(result_type __sd = default_seed)
2497        {seed(__sd, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2498    template<class _Sseq>
2499        _LIBCPP_INLINE_VISIBILITY
2500        typename enable_if
2501        <
2502            __is_seed_sequence<_Sseq, subtract_with_carry_engine>::value,
2503            void
2504        >::type
2505        seed(_Sseq& __q)
2506            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2507
2508    // generating functions
2509    result_type operator()();
2510    _LIBCPP_INLINE_VISIBILITY
2511    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2512
2513    template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2514    friend
2515    bool
2516    operator==(
2517        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2518        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2519
2520    template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2521    friend
2522    bool
2523    operator!=(
2524        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2525        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2526
2527    template <class _CharT, class _Traits,
2528              class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2529    friend
2530    basic_ostream<_CharT, _Traits>&
2531    operator<<(basic_ostream<_CharT, _Traits>& __os,
2532               const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2533
2534    template <class _CharT, class _Traits,
2535              class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2536    friend
2537    basic_istream<_CharT, _Traits>&
2538    operator>>(basic_istream<_CharT, _Traits>& __is,
2539               subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2540
2541private:
2542
2543    void seed(result_type __sd, integral_constant<unsigned, 1>);
2544    void seed(result_type __sd, integral_constant<unsigned, 2>);
2545    template<class _Sseq>
2546        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
2547    template<class _Sseq>
2548        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
2549};
2550
2551template<class _UIntType, size_t __w, size_t __s, size_t __r>
2552void
2553subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
2554        integral_constant<unsigned, 1>)
2555{
2556    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
2557        __e(__sd == 0u ? default_seed : __sd);
2558    for (size_t __i = 0; __i < __r; ++__i)
2559        __x_[__i] = static_cast<result_type>(__e() & _Max);
2560    __c_ = __x_[__r-1] == 0;
2561    __i_ = 0;
2562}
2563
2564template<class _UIntType, size_t __w, size_t __s, size_t __r>
2565void
2566subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
2567        integral_constant<unsigned, 2>)
2568{
2569    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
2570        __e(__sd == 0u ? default_seed : __sd);
2571    for (size_t __i = 0; __i < __r; ++__i)
2572    {
2573        result_type __e0 = __e();
2574        __x_[__i] = static_cast<result_type>(
2575                                    (__e0 + ((uint64_t)__e() << 32)) & _Max);
2576    }
2577    __c_ = __x_[__r-1] == 0;
2578    __i_ = 0;
2579}
2580
2581template<class _UIntType, size_t __w, size_t __s, size_t __r>
2582template<class _Sseq>
2583void
2584subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
2585        integral_constant<unsigned, 1>)
2586{
2587    const unsigned __k = 1;
2588    uint32_t __ar[__r * __k];
2589    __q.generate(__ar, __ar + __r * __k);
2590    for (size_t __i = 0; __i < __r; ++__i)
2591        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
2592    __c_ = __x_[__r-1] == 0;
2593    __i_ = 0;
2594}
2595
2596template<class _UIntType, size_t __w, size_t __s, size_t __r>
2597template<class _Sseq>
2598void
2599subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
2600        integral_constant<unsigned, 2>)
2601{
2602    const unsigned __k = 2;
2603    uint32_t __ar[__r * __k];
2604    __q.generate(__ar, __ar + __r * __k);
2605    for (size_t __i = 0; __i < __r; ++__i)
2606        __x_[__i] = static_cast<result_type>(
2607                  (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
2608    __c_ = __x_[__r-1] == 0;
2609    __i_ = 0;
2610}
2611
2612template<class _UIntType, size_t __w, size_t __s, size_t __r>
2613_UIntType
2614subtract_with_carry_engine<_UIntType, __w, __s, __r>::operator()()
2615{
2616    const result_type& __xs = __x_[(__i_ + (__r - __s)) % __r];
2617    result_type& __xr = __x_[__i_];
2618    result_type __new_c = __c_ == 0 ? __xs < __xr : __xs != 0 ? __xs <= __xr : 1;
2619    __xr = (__xs - __xr - __c_) & _Max;
2620    __c_ = __new_c;
2621    __i_ = (__i_ + 1) % __r;
2622    return __xr;
2623}
2624
2625template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2626bool
2627operator==(
2628    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2629    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y)
2630{
2631    if (__x.__c_ != __y.__c_)
2632        return false;
2633    if (__x.__i_ == __y.__i_)
2634        return _VSTD::equal(__x.__x_, __x.__x_ + _Rp, __y.__x_);
2635    if (__x.__i_ == 0 || __y.__i_ == 0)
2636    {
2637        size_t __j = _VSTD::min(_Rp - __x.__i_, _Rp - __y.__i_);
2638        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
2639                         __y.__x_ + __y.__i_))
2640            return false;
2641        if (__x.__i_ == 0)
2642            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Rp, __y.__x_);
2643        return _VSTD::equal(__x.__x_, __x.__x_ + (_Rp - __j), __y.__x_ + __j);
2644    }
2645    if (__x.__i_ < __y.__i_)
2646    {
2647        size_t __j = _Rp - __y.__i_;
2648        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
2649                         __y.__x_ + __y.__i_))
2650            return false;
2651        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Rp,
2652                         __y.__x_))
2653            return false;
2654        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
2655                           __y.__x_ + (_Rp - (__x.__i_ + __j)));
2656    }
2657    size_t __j = _Rp - __x.__i_;
2658    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
2659                     __x.__x_ + __x.__i_))
2660        return false;
2661    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Rp,
2662                     __x.__x_))
2663        return false;
2664    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
2665                       __x.__x_ + (_Rp - (__y.__i_ + __j)));
2666}
2667
2668template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2669inline _LIBCPP_INLINE_VISIBILITY
2670bool
2671operator!=(
2672    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2673    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y)
2674{
2675    return !(__x == __y);
2676}
2677
2678template <class _CharT, class _Traits,
2679          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2680basic_ostream<_CharT, _Traits>&
2681operator<<(basic_ostream<_CharT, _Traits>& __os,
2682           const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x)
2683{
2684    __save_flags<_CharT, _Traits> _(__os);
2685    __os.flags(ios_base::dec | ios_base::left);
2686    _CharT __sp = __os.widen(' ');
2687    __os.fill(__sp);
2688    __os << __x.__x_[__x.__i_];
2689    for (size_t __j = __x.__i_ + 1; __j < _Rp; ++__j)
2690        __os << __sp << __x.__x_[__j];
2691    for (size_t __j = 0; __j < __x.__i_; ++__j)
2692        __os << __sp << __x.__x_[__j];
2693    __os << __sp << __x.__c_;
2694    return __os;
2695}
2696
2697template <class _CharT, class _Traits,
2698          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2699basic_istream<_CharT, _Traits>&
2700operator>>(basic_istream<_CharT, _Traits>& __is,
2701           subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x)
2702{
2703    __save_flags<_CharT, _Traits> _(__is);
2704    __is.flags(ios_base::dec | ios_base::skipws);
2705    _UI __t[_Rp+1];
2706    for (size_t __i = 0; __i < _Rp+1; ++__i)
2707        __is >> __t[__i];
2708    if (!__is.fail())
2709    {
2710        for (size_t __i = 0; __i < _Rp; ++__i)
2711            __x.__x_[__i] = __t[__i];
2712        __x.__c_ = __t[_Rp];
2713        __x.__i_ = 0;
2714    }
2715    return __is;
2716}
2717
2718typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>     ranlux24_base;
2719typedef subtract_with_carry_engine<uint_fast64_t, 48,  5, 12>     ranlux48_base;
2720
2721// discard_block_engine
2722
2723template<class _Engine, size_t __p, size_t __r>
2724class _LIBCPP_VISIBLE discard_block_engine
2725{
2726    _Engine __e_;
2727    int     __n_;
2728
2729    static_assert(  0 <  __r, "discard_block_engine invalid parameters");
2730    static_assert(__r <= __p, "discard_block_engine invalid parameters");
2731public:
2732    // types
2733    typedef typename _Engine::result_type result_type;
2734
2735    // engine characteristics
2736    static _LIBCPP_CONSTEXPR const size_t block_size = __p;
2737    static _LIBCPP_CONSTEXPR const size_t used_block = __r;
2738
2739#ifdef _LIBCPP_HAS_NO_CONSTEXPR
2740    static const result_type _Min = _Engine::_Min;
2741    static const result_type _Max = _Engine::_Max;
2742#else
2743    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
2744    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
2745#endif
2746
2747    _LIBCPP_INLINE_VISIBILITY
2748    static _LIBCPP_CONSTEXPR result_type min() { return _Engine::min(); }
2749    _LIBCPP_INLINE_VISIBILITY
2750    static _LIBCPP_CONSTEXPR result_type max() { return _Engine::max(); }
2751
2752    // constructors and seeding functions
2753    _LIBCPP_INLINE_VISIBILITY
2754    discard_block_engine() : __n_(0) {}
2755    _LIBCPP_INLINE_VISIBILITY
2756    explicit discard_block_engine(const _Engine& __e)
2757        : __e_(__e), __n_(0) {}
2758#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2759    _LIBCPP_INLINE_VISIBILITY
2760    explicit discard_block_engine(_Engine&& __e)
2761        : __e_(_VSTD::move(__e)), __n_(0) {}
2762#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2763    _LIBCPP_INLINE_VISIBILITY
2764    explicit discard_block_engine(result_type __sd) : __e_(__sd), __n_(0) {}
2765    template<class _Sseq>
2766        _LIBCPP_INLINE_VISIBILITY
2767        explicit discard_block_engine(_Sseq& __q,
2768        typename enable_if<__is_seed_sequence<_Sseq, discard_block_engine>::value &&
2769                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
2770        : __e_(__q), __n_(0) {}
2771    _LIBCPP_INLINE_VISIBILITY
2772    void seed() {__e_.seed(); __n_ = 0;}
2773    _LIBCPP_INLINE_VISIBILITY
2774    void seed(result_type __sd) {__e_.seed(__sd); __n_ = 0;}
2775    template<class _Sseq>
2776        _LIBCPP_INLINE_VISIBILITY
2777        typename enable_if
2778        <
2779            __is_seed_sequence<_Sseq, discard_block_engine>::value,
2780            void
2781        >::type
2782        seed(_Sseq& __q) {__e_.seed(__q); __n_ = 0;}
2783
2784    // generating functions
2785    result_type operator()();
2786    _LIBCPP_INLINE_VISIBILITY
2787    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2788
2789    // property functions
2790    _LIBCPP_INLINE_VISIBILITY
2791    const _Engine& base() const {return __e_;}
2792
2793    template<class _Eng, size_t _Pp, size_t _Rp>
2794    friend
2795    bool
2796    operator==(
2797        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2798        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
2799
2800    template<class _Eng, size_t _Pp, size_t _Rp>
2801    friend
2802    bool
2803    operator!=(
2804        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2805        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
2806
2807    template <class _CharT, class _Traits,
2808              class _Eng, size_t _Pp, size_t _Rp>
2809    friend
2810    basic_ostream<_CharT, _Traits>&
2811    operator<<(basic_ostream<_CharT, _Traits>& __os,
2812               const discard_block_engine<_Eng, _Pp, _Rp>& __x);
2813
2814    template <class _CharT, class _Traits,
2815              class _Eng, size_t _Pp, size_t _Rp>
2816    friend
2817    basic_istream<_CharT, _Traits>&
2818    operator>>(basic_istream<_CharT, _Traits>& __is,
2819               discard_block_engine<_Eng, _Pp, _Rp>& __x);
2820};
2821
2822template<class _Engine, size_t __p, size_t __r>
2823typename discard_block_engine<_Engine, __p, __r>::result_type
2824discard_block_engine<_Engine, __p, __r>::operator()()
2825{
2826    if (__n_ >= __r)
2827    {
2828        __e_.discard(__p - __r);
2829        __n_ = 0;
2830    }
2831    ++__n_;
2832    return __e_();
2833}
2834
2835template<class _Eng, size_t _Pp, size_t _Rp>
2836inline _LIBCPP_INLINE_VISIBILITY
2837bool
2838operator==(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2839           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
2840{
2841    return __x.__n_ == __y.__n_ && __x.__e_ == __y.__e_;
2842}
2843
2844template<class _Eng, size_t _Pp, size_t _Rp>
2845inline _LIBCPP_INLINE_VISIBILITY
2846bool
2847operator!=(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2848           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
2849{
2850    return !(__x == __y);
2851}
2852
2853template <class _CharT, class _Traits,
2854          class _Eng, size_t _Pp, size_t _Rp>
2855basic_ostream<_CharT, _Traits>&
2856operator<<(basic_ostream<_CharT, _Traits>& __os,
2857           const discard_block_engine<_Eng, _Pp, _Rp>& __x)
2858{
2859    __save_flags<_CharT, _Traits> _(__os);
2860    __os.flags(ios_base::dec | ios_base::left);
2861    _CharT __sp = __os.widen(' ');
2862    __os.fill(__sp);
2863    return __os << __x.__e_ << __sp << __x.__n_;
2864}
2865
2866template <class _CharT, class _Traits,
2867          class _Eng, size_t _Pp, size_t _Rp>
2868basic_istream<_CharT, _Traits>&
2869operator>>(basic_istream<_CharT, _Traits>& __is,
2870           discard_block_engine<_Eng, _Pp, _Rp>& __x)
2871{
2872    __save_flags<_CharT, _Traits> _(__is);
2873    __is.flags(ios_base::dec | ios_base::skipws);
2874    _Eng __e;
2875    int __n;
2876    __is >> __e >> __n;
2877    if (!__is.fail())
2878    {
2879        __x.__e_ = __e;
2880        __x.__n_ = __n;
2881    }
2882    return __is;
2883}
2884
2885typedef discard_block_engine<ranlux24_base, 223, 23> ranlux24;
2886typedef discard_block_engine<ranlux48_base, 389, 11> ranlux48;
2887
2888// independent_bits_engine
2889
2890template<class _Engine, size_t __w, class _UIntType>
2891class _LIBCPP_VISIBLE independent_bits_engine
2892{
2893    template <class _UI, _UI _R0, size_t _Wp, size_t _Mp>
2894    class __get_n
2895    {
2896        static _LIBCPP_CONSTEXPR const size_t _Dt = numeric_limits<_UI>::digits;
2897        static _LIBCPP_CONSTEXPR const size_t _Np = _Wp / _Mp + (_Wp % _Mp != 0);
2898        static _LIBCPP_CONSTEXPR const size_t _W0 = _Wp / _Np;
2899        static _LIBCPP_CONSTEXPR const _UI _Y0 = _W0 >= _Dt ? 0 : (_R0 >> _W0) << _W0;
2900    public:
2901        static _LIBCPP_CONSTEXPR const size_t value = _R0 - _Y0 > _Y0 / _Np ? _Np + 1 : _Np;
2902    };
2903public:
2904    // types
2905    typedef _UIntType result_type;
2906
2907private:
2908    _Engine __e_;
2909
2910    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
2911    static_assert(  0 <  __w, "independent_bits_engine invalid parameters");
2912    static_assert(__w <= _Dt, "independent_bits_engine invalid parameters");
2913
2914    typedef typename _Engine::result_type _Engine_result_type;
2915    typedef typename conditional
2916        <
2917            sizeof(_Engine_result_type) <= sizeof(result_type),
2918                result_type,
2919                _Engine_result_type
2920        >::type _Working_result_type;
2921#ifdef _LIBCPP_HAS_NO_CONSTEXPR
2922    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
2923                                          + _Working_result_type(1);
2924#else
2925    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
2926                                                            + _Working_result_type(1);
2927#endif
2928    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
2929    static _LIBCPP_CONSTEXPR const size_t __n = __get_n<_Working_result_type, _Rp, __w, __m>::value;
2930    static _LIBCPP_CONSTEXPR const size_t __w0 = __w / __n;
2931    static _LIBCPP_CONSTEXPR const size_t __n0 = __n - __w % __n;
2932    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
2933    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
2934    static _LIBCPP_CONSTEXPR const _Working_result_type __y0 = __w0 >= _WDt ? 0 :
2935                                                               (_Rp >> __w0) << __w0;
2936    static _LIBCPP_CONSTEXPR const _Working_result_type __y1 = __w0 >= _WDt - 1 ? 0 :
2937                                                               (_Rp >> (__w0+1)) << (__w0+1);
2938    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask0 = __w0 > 0 ?
2939                                _Engine_result_type(~0) >> (_EDt - __w0) :
2940                                _Engine_result_type(0);
2941    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask1 = __w0 < _EDt - 1 ?
2942                                _Engine_result_type(~0) >> (_EDt - (__w0 + 1)) :
2943                                _Engine_result_type(~0);
2944public:
2945    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
2946    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
2947                                                      (result_type(1) << __w) - result_type(1);
2948    static_assert(_Min < _Max, "independent_bits_engine invalid parameters");
2949
2950    // engine characteristics
2951    _LIBCPP_INLINE_VISIBILITY
2952    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
2953    _LIBCPP_INLINE_VISIBILITY
2954    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
2955
2956    // constructors and seeding functions
2957    _LIBCPP_INLINE_VISIBILITY
2958    independent_bits_engine() {}
2959    _LIBCPP_INLINE_VISIBILITY
2960    explicit independent_bits_engine(const _Engine& __e)
2961        : __e_(__e) {}
2962#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2963    _LIBCPP_INLINE_VISIBILITY
2964    explicit independent_bits_engine(_Engine&& __e)
2965        : __e_(_VSTD::move(__e)) {}
2966#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2967    _LIBCPP_INLINE_VISIBILITY
2968    explicit independent_bits_engine(result_type __sd) : __e_(__sd) {}
2969    template<class _Sseq>
2970        _LIBCPP_INLINE_VISIBILITY
2971        explicit independent_bits_engine(_Sseq& __q,
2972        typename enable_if<__is_seed_sequence<_Sseq, independent_bits_engine>::value &&
2973                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
2974         : __e_(__q) {}
2975    _LIBCPP_INLINE_VISIBILITY
2976    void seed() {__e_.seed();}
2977    _LIBCPP_INLINE_VISIBILITY
2978    void seed(result_type __sd) {__e_.seed(__sd);}
2979    template<class _Sseq>
2980        _LIBCPP_INLINE_VISIBILITY
2981        typename enable_if
2982        <
2983            __is_seed_sequence<_Sseq, independent_bits_engine>::value,
2984            void
2985        >::type
2986        seed(_Sseq& __q) {__e_.seed(__q);}
2987
2988    // generating functions
2989    _LIBCPP_INLINE_VISIBILITY
2990    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
2991    _LIBCPP_INLINE_VISIBILITY
2992    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2993
2994    // property functions
2995    _LIBCPP_INLINE_VISIBILITY
2996    const _Engine& base() const {return __e_;}
2997
2998    template<class _Eng, size_t _Wp, class _UI>
2999    friend
3000    bool
3001    operator==(
3002        const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3003        const independent_bits_engine<_Eng, _Wp, _UI>& __y);
3004
3005    template<class _Eng, size_t _Wp, class _UI>
3006    friend
3007    bool
3008    operator!=(
3009        const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3010        const independent_bits_engine<_Eng, _Wp, _UI>& __y);
3011
3012    template <class _CharT, class _Traits,
3013              class _Eng, size_t _Wp, class _UI>
3014    friend
3015    basic_ostream<_CharT, _Traits>&
3016    operator<<(basic_ostream<_CharT, _Traits>& __os,
3017               const independent_bits_engine<_Eng, _Wp, _UI>& __x);
3018
3019    template <class _CharT, class _Traits,
3020              class _Eng, size_t _Wp, class _UI>
3021    friend
3022    basic_istream<_CharT, _Traits>&
3023    operator>>(basic_istream<_CharT, _Traits>& __is,
3024               independent_bits_engine<_Eng, _Wp, _UI>& __x);
3025
3026private:
3027    result_type __eval(false_type);
3028    result_type __eval(true_type);
3029
3030    template <size_t __count>
3031        _LIBCPP_INLINE_VISIBILITY
3032        static
3033        typename enable_if
3034        <
3035            __count < _Dt,
3036            result_type
3037        >::type
3038        __lshift(result_type __x) {return __x << __count;}
3039
3040    template <size_t __count>
3041        _LIBCPP_INLINE_VISIBILITY
3042        static
3043        typename enable_if
3044        <
3045            (__count >= _Dt),
3046            result_type
3047        >::type
3048        __lshift(result_type) {return result_type(0);}
3049};
3050
3051template<class _Engine, size_t __w, class _UIntType>
3052inline _LIBCPP_INLINE_VISIBILITY
3053_UIntType
3054independent_bits_engine<_Engine, __w, _UIntType>::__eval(false_type)
3055{
3056    return static_cast<result_type>(__e_() & __mask0);
3057}
3058
3059template<class _Engine, size_t __w, class _UIntType>
3060_UIntType
3061independent_bits_engine<_Engine, __w, _UIntType>::__eval(true_type)
3062{
3063    result_type _Sp = 0;
3064    for (size_t __k = 0; __k < __n0; ++__k)
3065    {
3066        _Engine_result_type __u;
3067        do
3068        {
3069            __u = __e_() - _Engine::min();
3070        } while (__u >= __y0);
3071        _Sp = static_cast<result_type>(__lshift<__w0>(_Sp) + (__u & __mask0));
3072    }
3073    for (size_t __k = __n0; __k < __n; ++__k)
3074    {
3075        _Engine_result_type __u;
3076        do
3077        {
3078            __u = __e_() - _Engine::min();
3079        } while (__u >= __y1);
3080        _Sp = static_cast<result_type>(__lshift<__w0+1>(_Sp) + (__u & __mask1));
3081    }
3082    return _Sp;
3083}
3084
3085template<class _Eng, size_t _Wp, class _UI>
3086inline _LIBCPP_INLINE_VISIBILITY
3087bool
3088operator==(
3089    const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3090    const independent_bits_engine<_Eng, _Wp, _UI>& __y)
3091{
3092    return __x.base() == __y.base();
3093}
3094
3095template<class _Eng, size_t _Wp, class _UI>
3096inline _LIBCPP_INLINE_VISIBILITY
3097bool
3098operator!=(
3099    const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3100    const independent_bits_engine<_Eng, _Wp, _UI>& __y)
3101{
3102    return !(__x == __y);
3103}
3104
3105template <class _CharT, class _Traits,
3106          class _Eng, size_t _Wp, class _UI>
3107basic_ostream<_CharT, _Traits>&
3108operator<<(basic_ostream<_CharT, _Traits>& __os,
3109           const independent_bits_engine<_Eng, _Wp, _UI>& __x)
3110{
3111    return __os << __x.base();
3112}
3113
3114template <class _CharT, class _Traits,
3115          class _Eng, size_t _Wp, class _UI>
3116basic_istream<_CharT, _Traits>&
3117operator>>(basic_istream<_CharT, _Traits>& __is,
3118           independent_bits_engine<_Eng, _Wp, _UI>& __x)
3119{
3120    _Eng __e;
3121    __is >> __e;
3122    if (!__is.fail())
3123        __x.__e_ = __e;
3124    return __is;
3125}
3126
3127// shuffle_order_engine
3128
3129template <uint64_t _Xp, uint64_t _Yp>
3130struct __ugcd
3131{
3132    static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
3133};
3134
3135template <uint64_t _Xp>
3136struct __ugcd<_Xp, 0>
3137{
3138    static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
3139};
3140
3141template <uint64_t _Np, uint64_t _Dp>
3142class __uratio
3143{
3144    static_assert(_Dp != 0, "__uratio divide by 0");
3145    static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
3146public:
3147    static _LIBCPP_CONSTEXPR const uint64_t num = _Np / __gcd;
3148    static _LIBCPP_CONSTEXPR const uint64_t den = _Dp / __gcd;
3149
3150    typedef __uratio<num, den> type;
3151};
3152
3153template<class _Engine, size_t __k>
3154class _LIBCPP_VISIBLE shuffle_order_engine
3155{
3156    static_assert(0 < __k, "shuffle_order_engine invalid parameters");
3157public:
3158    // types
3159    typedef typename _Engine::result_type result_type;
3160
3161private:
3162    _Engine __e_;
3163    result_type _V_[__k];
3164    result_type _Y_;
3165
3166public:
3167    // engine characteristics
3168    static _LIBCPP_CONSTEXPR const size_t table_size = __k;
3169
3170#ifdef _LIBCPP_HAS_NO_CONSTEXPR
3171    static const result_type _Min = _Engine::_Min;
3172    static const result_type _Max = _Engine::_Max;
3173#else
3174    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
3175    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
3176#endif
3177    static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
3178    _LIBCPP_INLINE_VISIBILITY
3179    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
3180    _LIBCPP_INLINE_VISIBILITY
3181    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
3182
3183    static _LIBCPP_CONSTEXPR const unsigned long long _Rp = _Max - _Min + 1ull;
3184
3185    // constructors and seeding functions
3186    _LIBCPP_INLINE_VISIBILITY
3187    shuffle_order_engine() {__init();}
3188    _LIBCPP_INLINE_VISIBILITY
3189    explicit shuffle_order_engine(const _Engine& __e)
3190        : __e_(__e) {__init();}
3191#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3192    _LIBCPP_INLINE_VISIBILITY
3193    explicit shuffle_order_engine(_Engine&& __e)
3194        : __e_(_VSTD::move(__e)) {__init();}
3195#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
3196    _LIBCPP_INLINE_VISIBILITY
3197    explicit shuffle_order_engine(result_type __sd) : __e_(__sd) {__init();}
3198    template<class _Sseq>
3199        _LIBCPP_INLINE_VISIBILITY
3200        explicit shuffle_order_engine(_Sseq& __q,
3201        typename enable_if<__is_seed_sequence<_Sseq, shuffle_order_engine>::value &&
3202                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
3203         : __e_(__q) {__init();}
3204    _LIBCPP_INLINE_VISIBILITY
3205    void seed() {__e_.seed(); __init();}
3206    _LIBCPP_INLINE_VISIBILITY
3207    void seed(result_type __sd) {__e_.seed(__sd); __init();}
3208    template<class _Sseq>
3209        _LIBCPP_INLINE_VISIBILITY
3210        typename enable_if
3211        <
3212            __is_seed_sequence<_Sseq, shuffle_order_engine>::value,
3213            void
3214        >::type
3215        seed(_Sseq& __q) {__e_.seed(__q); __init();}
3216
3217    // generating functions
3218    _LIBCPP_INLINE_VISIBILITY
3219    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
3220    _LIBCPP_INLINE_VISIBILITY
3221    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
3222
3223    // property functions
3224    _LIBCPP_INLINE_VISIBILITY
3225    const _Engine& base() const {return __e_;}
3226
3227private:
3228    template<class _Eng, size_t _Kp>
3229    friend
3230    bool
3231    operator==(
3232        const shuffle_order_engine<_Eng, _Kp>& __x,
3233        const shuffle_order_engine<_Eng, _Kp>& __y);
3234
3235    template<class _Eng, size_t _Kp>
3236    friend
3237    bool
3238    operator!=(
3239        const shuffle_order_engine<_Eng, _Kp>& __x,
3240        const shuffle_order_engine<_Eng, _Kp>& __y);
3241
3242    template <class _CharT, class _Traits,
3243              class _Eng, size_t _Kp>
3244    friend
3245    basic_ostream<_CharT, _Traits>&
3246    operator<<(basic_ostream<_CharT, _Traits>& __os,
3247               const shuffle_order_engine<_Eng, _Kp>& __x);
3248
3249    template <class _CharT, class _Traits,
3250              class _Eng, size_t _Kp>
3251    friend
3252    basic_istream<_CharT, _Traits>&
3253    operator>>(basic_istream<_CharT, _Traits>& __is,
3254               shuffle_order_engine<_Eng, _Kp>& __x);
3255
3256    _LIBCPP_INLINE_VISIBILITY
3257    void __init()
3258    {
3259        for (size_t __i = 0; __i < __k; ++__i)
3260            _V_[__i] = __e_();
3261        _Y_ = __e_();
3262    }
3263
3264    _LIBCPP_INLINE_VISIBILITY
3265    result_type __eval(false_type) {return __eval2(integral_constant<bool, __k & 1>());}
3266    _LIBCPP_INLINE_VISIBILITY
3267    result_type __eval(true_type) {return __eval(__uratio<__k, _Rp>());}
3268
3269    _LIBCPP_INLINE_VISIBILITY
3270    result_type __eval2(false_type) {return __eval(__uratio<__k/2, 0x8000000000000000ull>());}
3271    _LIBCPP_INLINE_VISIBILITY
3272    result_type __eval2(true_type) {return __evalf<__k, 0>();}
3273
3274    template <uint64_t _Np, uint64_t _Dp>
3275        _LIBCPP_INLINE_VISIBILITY
3276        typename enable_if
3277        <
3278            (__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)),
3279            result_type
3280        >::type
3281        __eval(__uratio<_Np, _Dp>)
3282            {return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();}
3283
3284    template <uint64_t _Np, uint64_t _Dp>
3285        _LIBCPP_INLINE_VISIBILITY
3286        typename enable_if
3287        <
3288            __uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min),
3289            result_type
3290        >::type
3291        __eval(__uratio<_Np, _Dp>)
3292        {
3293            const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (_Y_ - _Min)
3294                                                   / __uratio<_Np, _Dp>::den);
3295            _Y_ = _V_[__j];
3296            _V_[__j] = __e_();
3297            return _Y_;
3298        }
3299
3300    template <uint64_t __n, uint64_t __d>
3301        _LIBCPP_INLINE_VISIBILITY
3302        result_type __evalf()
3303        {
3304            const double _Fp = __d == 0 ?
3305                __n / (2. * 0x8000000000000000ull) :
3306                __n / (double)__d;
3307            const size_t __j = static_cast<size_t>(_Fp * (_Y_ - _Min));
3308            _Y_ = _V_[__j];
3309            _V_[__j] = __e_();
3310            return _Y_;
3311        }
3312};
3313
3314template<class _Eng, size_t _Kp>
3315bool
3316operator==(
3317    const shuffle_order_engine<_Eng, _Kp>& __x,
3318    const shuffle_order_engine<_Eng, _Kp>& __y)
3319{
3320    return __x._Y_ == __y._Y_ && _VSTD::equal(__x._V_, __x._V_ + _Kp, __y._V_) &&
3321           __x.__e_ == __y.__e_;
3322}
3323
3324template<class _Eng, size_t _Kp>
3325inline _LIBCPP_INLINE_VISIBILITY
3326bool
3327operator!=(
3328    const shuffle_order_engine<_Eng, _Kp>& __x,
3329    const shuffle_order_engine<_Eng, _Kp>& __y)
3330{
3331    return !(__x == __y);
3332}
3333
3334template <class _CharT, class _Traits,
3335          class _Eng, size_t _Kp>
3336basic_ostream<_CharT, _Traits>&
3337operator<<(basic_ostream<_CharT, _Traits>& __os,
3338           const shuffle_order_engine<_Eng, _Kp>& __x)
3339{
3340    __save_flags<_CharT, _Traits> _(__os);
3341    __os.flags(ios_base::dec | ios_base::left);
3342    _CharT __sp = __os.widen(' ');
3343    __os.fill(__sp);
3344    __os << __x.__e_ << __sp << __x._V_[0];
3345    for (size_t __i = 1; __i < _Kp; ++__i)
3346        __os << __sp << __x._V_[__i];
3347    return __os << __sp << __x._Y_;
3348}
3349
3350template <class _CharT, class _Traits,
3351          class _Eng, size_t _Kp>
3352basic_istream<_CharT, _Traits>&
3353operator>>(basic_istream<_CharT, _Traits>& __is,
3354           shuffle_order_engine<_Eng, _Kp>& __x)
3355{
3356    typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
3357    __save_flags<_CharT, _Traits> _(__is);
3358    __is.flags(ios_base::dec | ios_base::skipws);
3359    _Eng __e;
3360    result_type _Vp[_Kp+1];
3361    __is >> __e;
3362    for (size_t __i = 0; __i < _Kp+1; ++__i)
3363        __is >> _Vp[__i];
3364    if (!__is.fail())
3365    {
3366        __x.__e_ = __e;
3367        for (size_t __i = 0; __i < _Kp; ++__i)
3368            __x._V_[__i] = _Vp[__i];
3369        __x._Y_ = _Vp[_Kp];
3370    }
3371    return __is;
3372}
3373
3374typedef shuffle_order_engine<minstd_rand0, 256>                         knuth_b;
3375
3376// random_device
3377
3378class _LIBCPP_VISIBLE random_device
3379{
3380    int __f_;
3381public:
3382    // types
3383    typedef unsigned result_type;
3384
3385    // generator characteristics
3386    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
3387    static _LIBCPP_CONSTEXPR const result_type _Max = 0xFFFFFFFFu;
3388
3389    _LIBCPP_INLINE_VISIBILITY
3390    static _LIBCPP_CONSTEXPR result_type min() { return _Min;}
3391    _LIBCPP_INLINE_VISIBILITY
3392    static _LIBCPP_CONSTEXPR result_type max() { return _Max;}
3393
3394    // constructors
3395    explicit random_device(const string& __token = "/dev/urandom");
3396    ~random_device();
3397
3398    // generating functions
3399    result_type operator()();
3400
3401    // property functions
3402    double entropy() const;
3403
3404private:
3405    // no copy functions
3406    random_device(const random_device&); // = delete;
3407    random_device& operator=(const random_device&); // = delete;
3408};
3409
3410// seed_seq
3411
3412class _LIBCPP_VISIBLE seed_seq
3413{
3414public:
3415    // types
3416    typedef uint32_t result_type;
3417
3418private:
3419    vector<result_type> __v_;
3420
3421    template<class _InputIterator>
3422        void init(_InputIterator __first, _InputIterator __last);
3423public:
3424    // constructors
3425    _LIBCPP_INLINE_VISIBILITY
3426    seed_seq() {}
3427#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
3428    template<class _Tp>
3429        _LIBCPP_INLINE_VISIBILITY
3430        seed_seq(initializer_list<_Tp> __il) {init(__il.begin(), __il.end());}
3431#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
3432
3433    template<class _InputIterator>
3434        _LIBCPP_INLINE_VISIBILITY
3435        seed_seq(_InputIterator __first, _InputIterator __last)
3436             {init(__first, __last);}
3437
3438    // generating functions
3439    template<class _RandomAccessIterator>
3440        void generate(_RandomAccessIterator __first, _RandomAccessIterator __last);
3441
3442    // property functions
3443    _LIBCPP_INLINE_VISIBILITY
3444    size_t size() const {return __v_.size();}
3445    template<class _OutputIterator>
3446        _LIBCPP_INLINE_VISIBILITY
3447        void param(_OutputIterator __dest) const
3448            {_VSTD::copy(__v_.begin(), __v_.end(), __dest);}
3449
3450private:
3451    // no copy functions
3452    seed_seq(const seed_seq&); // = delete;
3453    void operator=(const seed_seq&); // = delete;
3454
3455    _LIBCPP_INLINE_VISIBILITY
3456    static result_type _Tp(result_type __x) {return __x ^ (__x >> 27);}
3457};
3458
3459template<class _InputIterator>
3460void
3461seed_seq::init(_InputIterator __first, _InputIterator __last)
3462{
3463    for (_InputIterator __s = __first; __s != __last; ++__s)
3464        __v_.push_back(*__s & 0xFFFFFFFF);
3465}
3466
3467template<class _RandomAccessIterator>
3468void
3469seed_seq::generate(_RandomAccessIterator __first, _RandomAccessIterator __last)
3470{
3471    if (__first != __last)
3472    {
3473        _VSTD::fill(__first, __last, 0x8b8b8b8b);
3474        const size_t __n = static_cast<size_t>(__last - __first);
3475        const size_t __s = __v_.size();
3476        const size_t __t = (__n >= 623) ? 11
3477                         : (__n >= 68) ? 7
3478                         : (__n >= 39) ? 5
3479                         : (__n >= 7)  ? 3
3480                         : (__n - 1) / 2;
3481        const size_t __p = (__n - __t) / 2;
3482        const size_t __q = __p + __t;
3483        const size_t __m = _VSTD::max(__s + 1, __n);
3484        // __k = 0;
3485        {
3486            result_type __r = 1664525 * _Tp(__first[0] ^ __first[__p]
3487                                                      ^  __first[__n - 1]);
3488            __first[__p] += __r;
3489            __r += __s;
3490            __first[__q] += __r;
3491            __first[0] = __r;
3492        }
3493        for (size_t __k = 1; __k <= __s; ++__k)
3494        {
3495            const size_t __kmodn = __k % __n;
3496            const size_t __kpmodn = (__k + __p) % __n;
3497            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
3498                                           ^ __first[(__k - 1) % __n]);
3499            __first[__kpmodn] += __r;
3500            __r +=  __kmodn + __v_[__k-1];
3501            __first[(__k + __q) % __n] += __r;
3502            __first[__kmodn] = __r;
3503        }
3504        for (size_t __k = __s + 1; __k < __m; ++__k)
3505        {
3506            const size_t __kmodn = __k % __n;
3507            const size_t __kpmodn = (__k + __p) % __n;
3508            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
3509                                           ^ __first[(__k - 1) % __n]);
3510            __first[__kpmodn] += __r;
3511            __r +=  __kmodn;
3512            __first[(__k + __q) % __n] += __r;
3513            __first[__kmodn] = __r;
3514        }
3515        for (size_t __k = __m; __k < __m + __n; ++__k)
3516        {
3517            const size_t __kmodn = __k % __n;
3518            const size_t __kpmodn = (__k + __p) % __n;
3519            result_type __r = 1566083941 * _Tp(__first[__kmodn] +
3520                                              __first[__kpmodn] +
3521                                              __first[(__k - 1) % __n]);
3522            __first[__kpmodn] ^= __r;
3523            __r -= __kmodn;
3524            __first[(__k + __q) % __n] ^= __r;
3525            __first[__kmodn] = __r;
3526        }
3527    }
3528}
3529
3530// generate_canonical
3531
3532template<class _RealType, size_t __bits, class _URNG>
3533_RealType
3534generate_canonical(_URNG& __g)
3535{
3536    const size_t _Dt = numeric_limits<_RealType>::digits;
3537    const size_t __b = _Dt < __bits ? _Dt : __bits;
3538#ifdef _LIBCPP_HAS_NO_CONSTEXPR
3539    const size_t __logR = __log2<uint64_t, _URNG::_Max - _URNG::_Min + uint64_t(1)>::value;
3540#else
3541    const size_t __logR = __log2<uint64_t, _URNG::max() - _URNG::min() + uint64_t(1)>::value;
3542#endif
3543    const size_t __k = __b / __logR + (__b % __logR != 0) + (__b == 0);
3544    const _RealType _Rp = _URNG::max() - _URNG::min() + _RealType(1);
3545    _RealType __base = _Rp;
3546    _RealType _Sp = __g() - _URNG::min();
3547    for (size_t __i = 1; __i < __k; ++__i, __base *= _Rp)
3548        _Sp += (__g() - _URNG::min()) * __base;
3549    return _Sp / __base;
3550}
3551
3552// uniform_int_distribution
3553
3554// in <algorithm>
3555
3556template <class _CharT, class _Traits, class _IT>
3557basic_ostream<_CharT, _Traits>&
3558operator<<(basic_ostream<_CharT, _Traits>& __os,
3559           const uniform_int_distribution<_IT>& __x)
3560{
3561    __save_flags<_CharT, _Traits> _(__os);
3562    __os.flags(ios_base::dec | ios_base::left);
3563    _CharT __sp = __os.widen(' ');
3564    __os.fill(__sp);
3565    return __os << __x.a() << __sp << __x.b();
3566}
3567
3568template <class _CharT, class _Traits, class _IT>
3569basic_istream<_CharT, _Traits>&
3570operator>>(basic_istream<_CharT, _Traits>& __is,
3571           uniform_int_distribution<_IT>& __x)
3572{
3573    typedef uniform_int_distribution<_IT> _Eng;
3574    typedef typename _Eng::result_type result_type;
3575    typedef typename _Eng::param_type param_type;
3576    __save_flags<_CharT, _Traits> _(__is);
3577    __is.flags(ios_base::dec | ios_base::skipws);
3578    result_type __a;
3579    result_type __b;
3580    __is >> __a >> __b;
3581    if (!__is.fail())
3582        __x.param(param_type(__a, __b));
3583    return __is;
3584}
3585
3586// uniform_real_distribution
3587
3588template<class _RealType = double>
3589class _LIBCPP_VISIBLE uniform_real_distribution
3590{
3591public:
3592    // types
3593    typedef _RealType result_type;
3594
3595    class _LIBCPP_VISIBLE param_type
3596    {
3597        result_type __a_;
3598        result_type __b_;
3599    public:
3600        typedef uniform_real_distribution distribution_type;
3601
3602        _LIBCPP_INLINE_VISIBILITY
3603        explicit param_type(result_type __a = 0,
3604                            result_type __b = 1)
3605            : __a_(__a), __b_(__b) {}
3606
3607        _LIBCPP_INLINE_VISIBILITY
3608        result_type a() const {return __a_;}
3609        _LIBCPP_INLINE_VISIBILITY
3610        result_type b() const {return __b_;}
3611
3612        friend _LIBCPP_INLINE_VISIBILITY
3613        bool operator==(const param_type& __x, const param_type& __y)
3614            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
3615        friend _LIBCPP_INLINE_VISIBILITY
3616        bool operator!=(const param_type& __x, const param_type& __y)
3617            {return !(__x == __y);}
3618    };
3619
3620private:
3621    param_type __p_;
3622
3623public:
3624    // constructors and reset functions
3625    _LIBCPP_INLINE_VISIBILITY
3626    explicit uniform_real_distribution(result_type __a = 0, result_type __b = 1)
3627        : __p_(param_type(__a, __b)) {}
3628    _LIBCPP_INLINE_VISIBILITY
3629    explicit uniform_real_distribution(const param_type& __p) : __p_(__p) {}
3630    _LIBCPP_INLINE_VISIBILITY
3631    void reset() {}
3632
3633    // generating functions
3634    template<class _URNG>
3635        _LIBCPP_INLINE_VISIBILITY
3636        result_type operator()(_URNG& __g)
3637        {return (*this)(__g, __p_);}
3638    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3639
3640    // property functions
3641    _LIBCPP_INLINE_VISIBILITY
3642    result_type a() const {return __p_.a();}
3643    _LIBCPP_INLINE_VISIBILITY
3644    result_type b() const {return __p_.b();}
3645
3646    _LIBCPP_INLINE_VISIBILITY
3647    param_type param() const {return __p_;}
3648    _LIBCPP_INLINE_VISIBILITY
3649    void param(const param_type& __p) {__p_ = __p;}
3650
3651    _LIBCPP_INLINE_VISIBILITY
3652    result_type min() const {return a();}
3653    _LIBCPP_INLINE_VISIBILITY
3654    result_type max() const {return b();}
3655
3656    friend _LIBCPP_INLINE_VISIBILITY
3657        bool operator==(const uniform_real_distribution& __x,
3658                        const uniform_real_distribution& __y)
3659        {return __x.__p_ == __y.__p_;}
3660    friend _LIBCPP_INLINE_VISIBILITY
3661        bool operator!=(const uniform_real_distribution& __x,
3662                        const uniform_real_distribution& __y)
3663        {return !(__x == __y);}
3664};
3665
3666template<class _RealType>
3667template<class _URNG>
3668inline _LIBCPP_INLINE_VISIBILITY
3669typename uniform_real_distribution<_RealType>::result_type
3670uniform_real_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
3671{
3672    return (__p.b() - __p.a())
3673        * _VSTD::generate_canonical<_RealType, numeric_limits<_RealType>::digits>(__g)
3674        + __p.a();
3675}
3676
3677template <class _CharT, class _Traits, class _RT>
3678basic_ostream<_CharT, _Traits>&
3679operator<<(basic_ostream<_CharT, _Traits>& __os,
3680           const uniform_real_distribution<_RT>& __x)
3681{
3682    __save_flags<_CharT, _Traits> _(__os);
3683    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
3684               ios_base::scientific);
3685    _CharT __sp = __os.widen(' ');
3686    __os.fill(__sp);
3687    return __os << __x.a() << __sp << __x.b();
3688}
3689
3690template <class _CharT, class _Traits, class _RT>
3691basic_istream<_CharT, _Traits>&
3692operator>>(basic_istream<_CharT, _Traits>& __is,
3693           uniform_real_distribution<_RT>& __x)
3694{
3695    typedef uniform_real_distribution<_RT> _Eng;
3696    typedef typename _Eng::result_type result_type;
3697    typedef typename _Eng::param_type param_type;
3698    __save_flags<_CharT, _Traits> _(__is);
3699    __is.flags(ios_base::dec | ios_base::skipws);
3700    result_type __a;
3701    result_type __b;
3702    __is >> __a >> __b;
3703    if (!__is.fail())
3704        __x.param(param_type(__a, __b));
3705    return __is;
3706}
3707
3708// bernoulli_distribution
3709
3710class _LIBCPP_VISIBLE bernoulli_distribution
3711{
3712public:
3713    // types
3714    typedef bool result_type;
3715
3716    class _LIBCPP_VISIBLE param_type
3717    {
3718        double __p_;
3719    public:
3720        typedef bernoulli_distribution distribution_type;
3721
3722        _LIBCPP_INLINE_VISIBILITY
3723        explicit param_type(double __p = 0.5) : __p_(__p) {}
3724
3725        _LIBCPP_INLINE_VISIBILITY
3726        double p() const {return __p_;}
3727
3728        friend _LIBCPP_INLINE_VISIBILITY
3729            bool operator==(const param_type& __x, const param_type& __y)
3730            {return __x.__p_ == __y.__p_;}
3731        friend _LIBCPP_INLINE_VISIBILITY
3732            bool operator!=(const param_type& __x, const param_type& __y)
3733            {return !(__x == __y);}
3734    };
3735
3736private:
3737    param_type __p_;
3738
3739public:
3740    // constructors and reset functions
3741    _LIBCPP_INLINE_VISIBILITY
3742    explicit bernoulli_distribution(double __p = 0.5)
3743        : __p_(param_type(__p)) {}
3744    _LIBCPP_INLINE_VISIBILITY
3745    explicit bernoulli_distribution(const param_type& __p) : __p_(__p) {}
3746    _LIBCPP_INLINE_VISIBILITY
3747    void reset() {}
3748
3749    // generating functions
3750    template<class _URNG>
3751        _LIBCPP_INLINE_VISIBILITY
3752        result_type operator()(_URNG& __g)
3753        {return (*this)(__g, __p_);}
3754    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3755
3756    // property functions
3757    _LIBCPP_INLINE_VISIBILITY
3758    double p() const {return __p_.p();}
3759
3760    _LIBCPP_INLINE_VISIBILITY
3761    param_type param() const {return __p_;}
3762    _LIBCPP_INLINE_VISIBILITY
3763    void param(const param_type& __p) {__p_ = __p;}
3764
3765    _LIBCPP_INLINE_VISIBILITY
3766    result_type min() const {return false;}
3767    _LIBCPP_INLINE_VISIBILITY
3768    result_type max() const {return true;}
3769
3770    friend _LIBCPP_INLINE_VISIBILITY
3771        bool operator==(const bernoulli_distribution& __x,
3772                        const bernoulli_distribution& __y)
3773        {return __x.__p_ == __y.__p_;}
3774    friend _LIBCPP_INLINE_VISIBILITY
3775        bool operator!=(const bernoulli_distribution& __x,
3776                        const bernoulli_distribution& __y)
3777        {return !(__x == __y);}
3778};
3779
3780template<class _URNG>
3781inline _LIBCPP_INLINE_VISIBILITY
3782bernoulli_distribution::result_type
3783bernoulli_distribution::operator()(_URNG& __g, const param_type& __p)
3784{
3785    uniform_real_distribution<double> __gen;
3786    return __gen(__g) < __p.p();
3787}
3788
3789template <class _CharT, class _Traits>
3790basic_ostream<_CharT, _Traits>&
3791operator<<(basic_ostream<_CharT, _Traits>& __os, const bernoulli_distribution& __x)
3792{
3793    __save_flags<_CharT, _Traits> _(__os);
3794    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
3795               ios_base::scientific);
3796    _CharT __sp = __os.widen(' ');
3797    __os.fill(__sp);
3798    return __os << __x.p();
3799}
3800
3801template <class _CharT, class _Traits>
3802basic_istream<_CharT, _Traits>&
3803operator>>(basic_istream<_CharT, _Traits>& __is, bernoulli_distribution& __x)
3804{
3805    typedef bernoulli_distribution _Eng;
3806    typedef typename _Eng::param_type param_type;
3807    __save_flags<_CharT, _Traits> _(__is);
3808    __is.flags(ios_base::dec | ios_base::skipws);
3809    double __p;
3810    __is >> __p;
3811    if (!__is.fail())
3812        __x.param(param_type(__p));
3813    return __is;
3814}
3815
3816// binomial_distribution
3817
3818template<class _IntType = int>
3819class _LIBCPP_VISIBLE binomial_distribution
3820{
3821public:
3822    // types
3823    typedef _IntType result_type;
3824
3825    class _LIBCPP_VISIBLE param_type
3826    {
3827        result_type __t_;
3828        double __p_;
3829        double __pr_;
3830        double __odds_ratio_;
3831        result_type __r0_;
3832    public:
3833        typedef binomial_distribution distribution_type;
3834
3835        explicit param_type(result_type __t = 1, double __p = 0.5);
3836
3837        _LIBCPP_INLINE_VISIBILITY
3838        result_type t() const {return __t_;}
3839        _LIBCPP_INLINE_VISIBILITY
3840        double p() const {return __p_;}
3841
3842        friend _LIBCPP_INLINE_VISIBILITY
3843            bool operator==(const param_type& __x, const param_type& __y)
3844            {return __x.__t_ == __y.__t_ && __x.__p_ == __y.__p_;}
3845        friend _LIBCPP_INLINE_VISIBILITY
3846            bool operator!=(const param_type& __x, const param_type& __y)
3847            {return !(__x == __y);}
3848
3849        friend class binomial_distribution;
3850    };
3851
3852private:
3853    param_type __p_;
3854
3855public:
3856    // constructors and reset functions
3857    _LIBCPP_INLINE_VISIBILITY
3858    explicit binomial_distribution(result_type __t = 1, double __p = 0.5)
3859        : __p_(param_type(__t, __p)) {}
3860    _LIBCPP_INLINE_VISIBILITY
3861    explicit binomial_distribution(const param_type& __p) : __p_(__p) {}
3862    _LIBCPP_INLINE_VISIBILITY
3863    void reset() {}
3864
3865    // generating functions
3866    template<class _URNG>
3867        _LIBCPP_INLINE_VISIBILITY
3868        result_type operator()(_URNG& __g)
3869        {return (*this)(__g, __p_);}
3870    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3871
3872    // property functions
3873    _LIBCPP_INLINE_VISIBILITY
3874    result_type t() const {return __p_.t();}
3875    _LIBCPP_INLINE_VISIBILITY
3876    double p() const {return __p_.p();}
3877
3878    _LIBCPP_INLINE_VISIBILITY
3879    param_type param() const {return __p_;}
3880    _LIBCPP_INLINE_VISIBILITY
3881    void param(const param_type& __p) {__p_ = __p;}
3882
3883    _LIBCPP_INLINE_VISIBILITY
3884    result_type min() const {return 0;}
3885    _LIBCPP_INLINE_VISIBILITY
3886    result_type max() const {return t();}
3887
3888    friend _LIBCPP_INLINE_VISIBILITY
3889        bool operator==(const binomial_distribution& __x,
3890                        const binomial_distribution& __y)
3891        {return __x.__p_ == __y.__p_;}
3892    friend _LIBCPP_INLINE_VISIBILITY
3893        bool operator!=(const binomial_distribution& __x,
3894                        const binomial_distribution& __y)
3895        {return !(__x == __y);}
3896};
3897
3898template<class _IntType>
3899binomial_distribution<_IntType>::param_type::param_type(result_type __t, double __p)
3900    : __t_(__t), __p_(__p)
3901{
3902    if (0 < __p_ && __p_ < 1)
3903    {
3904        __r0_ = static_cast<result_type>((__t_ + 1) * __p_);
3905        __pr_ = _VSTD::exp(_VSTD::lgamma(__t_ + 1.) - _VSTD::lgamma(__r0_ + 1.) -
3906                          _VSTD::lgamma(__t_ - __r0_ + 1.) + __r0_ * _VSTD::log(__p_) +
3907                          (__t_ - __r0_) * _VSTD::log(1 - __p_));
3908        __odds_ratio_ = __p_ / (1 - __p_);
3909    }
3910}
3911
3912template<class _IntType>
3913template<class _URNG>
3914_IntType
3915binomial_distribution<_IntType>::operator()(_URNG& __g, const param_type& __pr)
3916{
3917    if (__pr.__t_ == 0 || __pr.__p_ == 0)
3918        return 0;
3919    if (__pr.__p_ == 1)
3920        return __pr.__t_;
3921    uniform_real_distribution<double> __gen;
3922    double __u = __gen(__g) - __pr.__pr_;
3923    if (__u < 0)
3924        return __pr.__r0_;
3925    double __pu = __pr.__pr_;
3926    double __pd = __pu;
3927    result_type __ru = __pr.__r0_;
3928    result_type __rd = __ru;
3929    while (true)
3930    {
3931        if (__rd >= 1)
3932        {
3933            __pd *= __rd / (__pr.__odds_ratio_ * (__pr.__t_ - __rd + 1));
3934            __u -= __pd;
3935            if (__u < 0)
3936                return __rd - 1;
3937        }
3938        --__rd;
3939        ++__ru;
3940        if (__ru <= __pr.__t_)
3941        {
3942            __pu *= (__pr.__t_ - __ru + 1) * __pr.__odds_ratio_ / __ru;
3943            __u -= __pu;
3944            if (__u < 0)
3945                return __ru;
3946        }
3947    }
3948}
3949
3950template <class _CharT, class _Traits, class _IntType>
3951basic_ostream<_CharT, _Traits>&
3952operator<<(basic_ostream<_CharT, _Traits>& __os,
3953           const binomial_distribution<_IntType>& __x)
3954{
3955    __save_flags<_CharT, _Traits> _(__os);
3956    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
3957               ios_base::scientific);
3958    _CharT __sp = __os.widen(' ');
3959    __os.fill(__sp);
3960    return __os << __x.t() << __sp << __x.p();
3961}
3962
3963template <class _CharT, class _Traits, class _IntType>
3964basic_istream<_CharT, _Traits>&
3965operator>>(basic_istream<_CharT, _Traits>& __is,
3966           binomial_distribution<_IntType>& __x)
3967{
3968    typedef binomial_distribution<_IntType> _Eng;
3969    typedef typename _Eng::result_type result_type;
3970    typedef typename _Eng::param_type param_type;
3971    __save_flags<_CharT, _Traits> _(__is);
3972    __is.flags(ios_base::dec | ios_base::skipws);
3973    result_type __t;
3974    double __p;
3975    __is >> __t >> __p;
3976    if (!__is.fail())
3977        __x.param(param_type(__t, __p));
3978    return __is;
3979}
3980
3981// exponential_distribution
3982
3983template<class _RealType = double>
3984class _LIBCPP_VISIBLE exponential_distribution
3985{
3986public:
3987    // types
3988    typedef _RealType result_type;
3989
3990    class _LIBCPP_VISIBLE param_type
3991    {
3992        result_type __lambda_;
3993    public:
3994        typedef exponential_distribution distribution_type;
3995
3996        _LIBCPP_INLINE_VISIBILITY
3997        explicit param_type(result_type __lambda = 1) : __lambda_(__lambda) {}
3998
3999        _LIBCPP_INLINE_VISIBILITY
4000        result_type lambda() const {return __lambda_;}
4001
4002        friend _LIBCPP_INLINE_VISIBILITY
4003            bool operator==(const param_type& __x, const param_type& __y)
4004            {return __x.__lambda_ == __y.__lambda_;}
4005        friend _LIBCPP_INLINE_VISIBILITY
4006            bool operator!=(const param_type& __x, const param_type& __y)
4007            {return !(__x == __y);}
4008    };
4009
4010private:
4011    param_type __p_;
4012
4013public:
4014    // constructors and reset functions
4015    _LIBCPP_INLINE_VISIBILITY
4016    explicit exponential_distribution(result_type __lambda = 1)
4017        : __p_(param_type(__lambda)) {}
4018    _LIBCPP_INLINE_VISIBILITY
4019    explicit exponential_distribution(const param_type& __p) : __p_(__p) {}
4020    _LIBCPP_INLINE_VISIBILITY
4021    void reset() {}
4022
4023    // generating functions
4024    template<class _URNG>
4025        _LIBCPP_INLINE_VISIBILITY
4026        result_type operator()(_URNG& __g)
4027        {return (*this)(__g, __p_);}
4028    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4029
4030    // property functions
4031    _LIBCPP_INLINE_VISIBILITY
4032    result_type lambda() const {return __p_.lambda();}
4033
4034    _LIBCPP_INLINE_VISIBILITY
4035    param_type param() const {return __p_;}
4036    _LIBCPP_INLINE_VISIBILITY
4037    void param(const param_type& __p) {__p_ = __p;}
4038
4039    _LIBCPP_INLINE_VISIBILITY
4040    result_type min() const {return 0;}
4041    _LIBCPP_INLINE_VISIBILITY
4042    result_type max() const {return numeric_limits<result_type>::infinity();}
4043
4044    friend _LIBCPP_INLINE_VISIBILITY
4045        bool operator==(const exponential_distribution& __x,
4046                        const exponential_distribution& __y)
4047        {return __x.__p_ == __y.__p_;}
4048    friend _LIBCPP_INLINE_VISIBILITY
4049        bool operator!=(const exponential_distribution& __x,
4050                        const exponential_distribution& __y)
4051        {return !(__x == __y);}
4052};
4053
4054template <class _RealType>
4055template<class _URNG>
4056_RealType
4057exponential_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4058{
4059    return -_VSTD::log
4060                  (
4061                      result_type(1) -
4062                      _VSTD::generate_canonical<result_type,
4063                                       numeric_limits<result_type>::digits>(__g)
4064                  )
4065                  / __p.lambda();
4066}
4067
4068template <class _CharT, class _Traits, class _RealType>
4069basic_ostream<_CharT, _Traits>&
4070operator<<(basic_ostream<_CharT, _Traits>& __os,
4071           const exponential_distribution<_RealType>& __x)
4072{
4073    __save_flags<_CharT, _Traits> _(__os);
4074    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4075               ios_base::scientific);
4076    return __os << __x.lambda();
4077}
4078
4079template <class _CharT, class _Traits, class _RealType>
4080basic_istream<_CharT, _Traits>&
4081operator>>(basic_istream<_CharT, _Traits>& __is,
4082           exponential_distribution<_RealType>& __x)
4083{
4084    typedef exponential_distribution<_RealType> _Eng;
4085    typedef typename _Eng::result_type result_type;
4086    typedef typename _Eng::param_type param_type;
4087    __save_flags<_CharT, _Traits> _(__is);
4088    __is.flags(ios_base::dec | ios_base::skipws);
4089    result_type __lambda;
4090    __is >> __lambda;
4091    if (!__is.fail())
4092        __x.param(param_type(__lambda));
4093    return __is;
4094}
4095
4096// normal_distribution
4097
4098template<class _RealType = double>
4099class _LIBCPP_VISIBLE normal_distribution
4100{
4101public:
4102    // types
4103    typedef _RealType result_type;
4104
4105    class _LIBCPP_VISIBLE param_type
4106    {
4107        result_type __mean_;
4108        result_type __stddev_;
4109    public:
4110        typedef normal_distribution distribution_type;
4111
4112        _LIBCPP_INLINE_VISIBILITY
4113        explicit param_type(result_type __mean = 0, result_type __stddev = 1)
4114            : __mean_(__mean), __stddev_(__stddev) {}
4115
4116        _LIBCPP_INLINE_VISIBILITY
4117        result_type mean() const {return __mean_;}
4118        _LIBCPP_INLINE_VISIBILITY
4119        result_type stddev() const {return __stddev_;}
4120
4121        friend _LIBCPP_INLINE_VISIBILITY
4122            bool operator==(const param_type& __x, const param_type& __y)
4123            {return __x.__mean_ == __y.__mean_ && __x.__stddev_ == __y.__stddev_;}
4124        friend _LIBCPP_INLINE_VISIBILITY
4125            bool operator!=(const param_type& __x, const param_type& __y)
4126            {return !(__x == __y);}
4127    };
4128
4129private:
4130    param_type __p_;
4131    result_type _V_;
4132    bool _V_hot_;
4133
4134public:
4135    // constructors and reset functions
4136    _LIBCPP_INLINE_VISIBILITY
4137    explicit normal_distribution(result_type __mean = 0, result_type __stddev = 1)
4138        : __p_(param_type(__mean, __stddev)), _V_hot_(false) {}
4139    _LIBCPP_INLINE_VISIBILITY
4140    explicit normal_distribution(const param_type& __p)
4141        : __p_(__p), _V_hot_(false) {}
4142    _LIBCPP_INLINE_VISIBILITY
4143    void reset() {_V_hot_ = false;}
4144
4145    // generating functions
4146    template<class _URNG>
4147        _LIBCPP_INLINE_VISIBILITY
4148        result_type operator()(_URNG& __g)
4149        {return (*this)(__g, __p_);}
4150    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4151
4152    // property functions
4153    _LIBCPP_INLINE_VISIBILITY
4154    result_type mean() const {return __p_.mean();}
4155    _LIBCPP_INLINE_VISIBILITY
4156    result_type stddev() const {return __p_.stddev();}
4157
4158    _LIBCPP_INLINE_VISIBILITY
4159    param_type param() const {return __p_;}
4160    _LIBCPP_INLINE_VISIBILITY
4161    void param(const param_type& __p) {__p_ = __p;}
4162
4163    _LIBCPP_INLINE_VISIBILITY
4164    result_type min() const {return -numeric_limits<result_type>::infinity();}
4165    _LIBCPP_INLINE_VISIBILITY
4166    result_type max() const {return numeric_limits<result_type>::infinity();}
4167
4168    friend _LIBCPP_INLINE_VISIBILITY
4169        bool operator==(const normal_distribution& __x,
4170                        const normal_distribution& __y)
4171        {return __x.__p_ == __y.__p_ && __x._V_hot_ == __y._V_hot_ &&
4172                (!__x._V_hot_ || __x._V_ == __y._V_);}
4173    friend _LIBCPP_INLINE_VISIBILITY
4174        bool operator!=(const normal_distribution& __x,
4175                        const normal_distribution& __y)
4176        {return !(__x == __y);}
4177
4178    template <class _CharT, class _Traits, class _RT>
4179    friend
4180    basic_ostream<_CharT, _Traits>&
4181    operator<<(basic_ostream<_CharT, _Traits>& __os,
4182               const normal_distribution<_RT>& __x);
4183
4184    template <class _CharT, class _Traits, class _RT>
4185    friend
4186    basic_istream<_CharT, _Traits>&
4187    operator>>(basic_istream<_CharT, _Traits>& __is,
4188               normal_distribution<_RT>& __x);
4189};
4190
4191template <class _RealType>
4192template<class _URNG>
4193_RealType
4194normal_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4195{
4196    result_type _Up;
4197    if (_V_hot_)
4198    {
4199        _V_hot_ = false;
4200        _Up = _V_;
4201    }
4202    else
4203    {
4204        uniform_real_distribution<result_type> _Uni(-1, 1);
4205        result_type __u;
4206        result_type __v;
4207        result_type __s;
4208        do
4209        {
4210            __u = _Uni(__g);
4211            __v = _Uni(__g);
4212            __s = __u * __u + __v * __v;
4213        } while (__s > 1 || __s == 0);
4214        result_type _Fp = _VSTD::sqrt(-2 * _VSTD::log(__s) / __s);
4215        _V_ = __v * _Fp;
4216        _V_hot_ = true;
4217        _Up = __u * _Fp;
4218    }
4219    return _Up * __p.stddev() + __p.mean();
4220}
4221
4222template <class _CharT, class _Traits, class _RT>
4223basic_ostream<_CharT, _Traits>&
4224operator<<(basic_ostream<_CharT, _Traits>& __os,
4225           const normal_distribution<_RT>& __x)
4226{
4227    __save_flags<_CharT, _Traits> _(__os);
4228    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4229               ios_base::scientific);
4230    _CharT __sp = __os.widen(' ');
4231    __os.fill(__sp);
4232    __os << __x.mean() << __sp << __x.stddev() << __sp << __x._V_hot_;
4233    if (__x._V_hot_)
4234        __os << __sp << __x._V_;
4235    return __os;
4236}
4237
4238template <class _CharT, class _Traits, class _RT>
4239basic_istream<_CharT, _Traits>&
4240operator>>(basic_istream<_CharT, _Traits>& __is,
4241           normal_distribution<_RT>& __x)
4242{
4243    typedef normal_distribution<_RT> _Eng;
4244    typedef typename _Eng::result_type result_type;
4245    typedef typename _Eng::param_type param_type;
4246    __save_flags<_CharT, _Traits> _(__is);
4247    __is.flags(ios_base::dec | ios_base::skipws);
4248    result_type __mean;
4249    result_type __stddev;
4250    result_type _Vp = 0;
4251    bool _V_hot = false;
4252    __is >> __mean >> __stddev >> _V_hot;
4253    if (_V_hot)
4254        __is >> _Vp;
4255    if (!__is.fail())
4256    {
4257        __x.param(param_type(__mean, __stddev));
4258        __x._V_hot_ = _V_hot;
4259        __x._V_ = _Vp;
4260    }
4261    return __is;
4262}
4263
4264// lognormal_distribution
4265
4266template<class _RealType = double>
4267class _LIBCPP_VISIBLE lognormal_distribution
4268{
4269public:
4270    // types
4271    typedef _RealType result_type;
4272
4273    class _LIBCPP_VISIBLE param_type
4274    {
4275        normal_distribution<result_type> __nd_;
4276    public:
4277        typedef lognormal_distribution distribution_type;
4278
4279        _LIBCPP_INLINE_VISIBILITY
4280        explicit param_type(result_type __m = 0, result_type __s = 1)
4281            : __nd_(__m, __s) {}
4282
4283        _LIBCPP_INLINE_VISIBILITY
4284        result_type m() const {return __nd_.mean();}
4285        _LIBCPP_INLINE_VISIBILITY
4286        result_type s() const {return __nd_.stddev();}
4287
4288        friend _LIBCPP_INLINE_VISIBILITY
4289            bool operator==(const param_type& __x, const param_type& __y)
4290            {return __x.__nd_ == __y.__nd_;}
4291        friend _LIBCPP_INLINE_VISIBILITY
4292            bool operator!=(const param_type& __x, const param_type& __y)
4293            {return !(__x == __y);}
4294        friend class lognormal_distribution;
4295
4296        template <class _CharT, class _Traits, class _RT>
4297        friend
4298        basic_ostream<_CharT, _Traits>&
4299        operator<<(basic_ostream<_CharT, _Traits>& __os,
4300                   const lognormal_distribution<_RT>& __x);
4301
4302        template <class _CharT, class _Traits, class _RT>
4303        friend
4304        basic_istream<_CharT, _Traits>&
4305        operator>>(basic_istream<_CharT, _Traits>& __is,
4306                   lognormal_distribution<_RT>& __x);
4307    };
4308
4309private:
4310    param_type __p_;
4311
4312public:
4313    // constructor and reset functions
4314    _LIBCPP_INLINE_VISIBILITY
4315    explicit lognormal_distribution(result_type __m = 0, result_type __s = 1)
4316        : __p_(param_type(__m, __s)) {}
4317    _LIBCPP_INLINE_VISIBILITY
4318    explicit lognormal_distribution(const param_type& __p)
4319        : __p_(__p) {}
4320    _LIBCPP_INLINE_VISIBILITY
4321    void reset() {__p_.__nd_.reset();}
4322
4323    // generating functions
4324    template<class _URNG>
4325        _LIBCPP_INLINE_VISIBILITY
4326        result_type operator()(_URNG& __g)
4327        {return (*this)(__g, __p_);}
4328    template<class _URNG>
4329        _LIBCPP_INLINE_VISIBILITY
4330        result_type operator()(_URNG& __g, const param_type& __p)
4331        {return _VSTD::exp(const_cast<normal_distribution<result_type>&>(__p.__nd_)(__g));}
4332
4333    // property functions
4334    _LIBCPP_INLINE_VISIBILITY
4335    result_type m() const {return __p_.m();}
4336    _LIBCPP_INLINE_VISIBILITY
4337    result_type s() const {return __p_.s();}
4338
4339    _LIBCPP_INLINE_VISIBILITY
4340    param_type param() const {return __p_;}
4341    _LIBCPP_INLINE_VISIBILITY
4342    void param(const param_type& __p) {__p_ = __p;}
4343
4344    _LIBCPP_INLINE_VISIBILITY
4345    result_type min() const {return 0;}
4346    _LIBCPP_INLINE_VISIBILITY
4347    result_type max() const {return numeric_limits<result_type>::infinity();}
4348
4349    friend _LIBCPP_INLINE_VISIBILITY
4350        bool operator==(const lognormal_distribution& __x,
4351                        const lognormal_distribution& __y)
4352        {return __x.__p_ == __y.__p_;}
4353    friend _LIBCPP_INLINE_VISIBILITY
4354        bool operator!=(const lognormal_distribution& __x,
4355                        const lognormal_distribution& __y)
4356        {return !(__x == __y);}
4357
4358    template <class _CharT, class _Traits, class _RT>
4359    friend
4360    basic_ostream<_CharT, _Traits>&
4361    operator<<(basic_ostream<_CharT, _Traits>& __os,
4362               const lognormal_distribution<_RT>& __x);
4363
4364    template <class _CharT, class _Traits, class _RT>
4365    friend
4366    basic_istream<_CharT, _Traits>&
4367    operator>>(basic_istream<_CharT, _Traits>& __is,
4368               lognormal_distribution<_RT>& __x);
4369};
4370
4371template <class _CharT, class _Traits, class _RT>
4372inline _LIBCPP_INLINE_VISIBILITY
4373basic_ostream<_CharT, _Traits>&
4374operator<<(basic_ostream<_CharT, _Traits>& __os,
4375           const lognormal_distribution<_RT>& __x)
4376{
4377    return __os << __x.__p_.__nd_;
4378}
4379
4380template <class _CharT, class _Traits, class _RT>
4381inline _LIBCPP_INLINE_VISIBILITY
4382basic_istream<_CharT, _Traits>&
4383operator>>(basic_istream<_CharT, _Traits>& __is,
4384           lognormal_distribution<_RT>& __x)
4385{
4386    return __is >> __x.__p_.__nd_;
4387}
4388
4389// poisson_distribution
4390
4391template<class _IntType = int>
4392class _LIBCPP_VISIBLE poisson_distribution
4393{
4394public:
4395    // types
4396    typedef _IntType result_type;
4397
4398    class _LIBCPP_VISIBLE param_type
4399    {
4400        double __mean_;
4401        double __s_;
4402        double __d_;
4403        double __l_;
4404        double __omega_;
4405        double __c0_;
4406        double __c1_;
4407        double __c2_;
4408        double __c3_;
4409        double __c_;
4410
4411    public:
4412        typedef poisson_distribution distribution_type;
4413
4414        explicit param_type(double __mean = 1.0);
4415
4416        _LIBCPP_INLINE_VISIBILITY
4417        double mean() const {return __mean_;}
4418
4419        friend _LIBCPP_INLINE_VISIBILITY
4420            bool operator==(const param_type& __x, const param_type& __y)
4421            {return __x.__mean_ == __y.__mean_;}
4422        friend _LIBCPP_INLINE_VISIBILITY
4423            bool operator!=(const param_type& __x, const param_type& __y)
4424            {return !(__x == __y);}
4425
4426        friend class poisson_distribution;
4427    };
4428
4429private:
4430    param_type __p_;
4431
4432public:
4433    // constructors and reset functions
4434    _LIBCPP_INLINE_VISIBILITY
4435    explicit poisson_distribution(double __mean = 1.0) : __p_(__mean) {}
4436    _LIBCPP_INLINE_VISIBILITY
4437    explicit poisson_distribution(const param_type& __p) : __p_(__p) {}
4438    _LIBCPP_INLINE_VISIBILITY
4439    void reset() {}
4440
4441    // generating functions
4442    template<class _URNG>
4443        _LIBCPP_INLINE_VISIBILITY
4444        result_type operator()(_URNG& __g)
4445        {return (*this)(__g, __p_);}
4446    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4447
4448    // property functions
4449    _LIBCPP_INLINE_VISIBILITY
4450    double mean() const {return __p_.mean();}
4451
4452    _LIBCPP_INLINE_VISIBILITY
4453    param_type param() const {return __p_;}
4454    _LIBCPP_INLINE_VISIBILITY
4455    void param(const param_type& __p) {__p_ = __p;}
4456
4457    _LIBCPP_INLINE_VISIBILITY
4458    result_type min() const {return 0;}
4459    _LIBCPP_INLINE_VISIBILITY
4460    result_type max() const {return numeric_limits<result_type>::max();}
4461
4462    friend _LIBCPP_INLINE_VISIBILITY
4463        bool operator==(const poisson_distribution& __x,
4464                        const poisson_distribution& __y)
4465        {return __x.__p_ == __y.__p_;}
4466    friend _LIBCPP_INLINE_VISIBILITY
4467        bool operator!=(const poisson_distribution& __x,
4468                        const poisson_distribution& __y)
4469        {return !(__x == __y);}
4470};
4471
4472template<class _IntType>
4473poisson_distribution<_IntType>::param_type::param_type(double __mean)
4474    : __mean_(__mean)
4475{
4476    if (__mean_ < 10)
4477    {
4478        __s_ = 0;
4479        __d_ = 0;
4480        __l_ = _VSTD::exp(-__mean_);
4481        __omega_ = 0;
4482        __c3_ = 0;
4483        __c2_ = 0;
4484        __c1_ = 0;
4485        __c0_ = 0;
4486        __c_ = 0;
4487    }
4488    else
4489    {
4490        __s_ = _VSTD::sqrt(__mean_);
4491        __d_ = 6 * __mean_ * __mean_;
4492        __l_ = static_cast<result_type>(__mean_ - 1.1484);
4493        __omega_ = .3989423 / __s_;
4494        double __b1_ = .4166667E-1 / __mean_;
4495        double __b2_ = .3 * __b1_ * __b1_;
4496        __c3_ = .1428571 * __b1_ * __b2_;
4497        __c2_ = __b2_ - 15. * __c3_;
4498        __c1_ = __b1_ - 6. * __b2_ + 45. * __c3_;
4499        __c0_ = 1. - __b1_ + 3. * __b2_ - 15. * __c3_;
4500        __c_ = .1069 / __mean_;
4501    }
4502}
4503
4504template <class _IntType>
4505template<class _URNG>
4506_IntType
4507poisson_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
4508{
4509    result_type __x;
4510    uniform_real_distribution<double> __urd;
4511    if (__pr.__mean_ < 10)
4512    {
4513         __x = 0;
4514        for (double __p = __urd(__urng); __p > __pr.__l_; ++__x)
4515            __p *= __urd(__urng);
4516    }
4517    else
4518    {
4519        double __difmuk;
4520        double __g = __pr.__mean_ + __pr.__s_ * normal_distribution<double>()(__urng);
4521        double __u;
4522        if (__g > 0)
4523        {
4524            __x = static_cast<result_type>(__g);
4525            if (__x >= __pr.__l_)
4526                return __x;
4527            __difmuk = __pr.__mean_ - __x;
4528            __u = __urd(__urng);
4529            if (__pr.__d_ * __u >= __difmuk * __difmuk * __difmuk)
4530                return __x;
4531        }
4532        exponential_distribution<double> __edist;
4533        for (bool __using_exp_dist = false; true; __using_exp_dist = true)
4534        {
4535            double __e;
4536            if (__using_exp_dist || __g < 0)
4537            {
4538                double __t;
4539                do
4540                {
4541                    __e = __edist(__urng);
4542                    __u = __urd(__urng);
4543                    __u += __u - 1;
4544                    __t = 1.8 + (__u < 0 ? -__e : __e);
4545                } while (__t <= -.6744);
4546                __x = __pr.__mean_ + __pr.__s_ * __t;
4547                __difmuk = __pr.__mean_ - __x;
4548                __using_exp_dist = true;
4549            }
4550            double __px;
4551            double __py;
4552            if (__x < 10)
4553            {
4554                const result_type __fac[] = {1, 1, 2, 6, 24, 120, 720, 5040,
4555                                             40320, 362880};
4556                __px = -__pr.__mean_;
4557                __py = _VSTD::pow(__pr.__mean_, (double)__x) / __fac[__x];
4558            }
4559            else
4560            {
4561                double __del = .8333333E-1 / __x;
4562                __del -= 4.8 * __del * __del * __del;
4563                double __v = __difmuk / __x;
4564                if (_VSTD::abs(__v) > 0.25)
4565                    __px = __x * _VSTD::log(1 + __v) - __difmuk - __del;
4566                else
4567                    __px = __x * __v * __v * (((((((.1250060 * __v + -.1384794) *
4568                           __v + .1421878) * __v + -.1661269) * __v + .2000118) *
4569                           __v + -.2500068) * __v + .3333333) * __v + -.5) - __del;
4570                __py = .3989423 / _VSTD::sqrt(__x);
4571            }
4572            double __r = (0.5 - __difmuk) / __pr.__s_;
4573            double __r2 = __r * __r;
4574            double __fx = -0.5 * __r2;
4575            double __fy = __pr.__omega_ * (((__pr.__c3_ * __r2 + __pr.__c2_) *
4576                                        __r2 + __pr.__c1_) * __r2 + __pr.__c0_);
4577            if (__using_exp_dist)
4578            {
4579                if (__pr.__c_ * _VSTD::abs(__u) <= __py * _VSTD::exp(__px + __e) -
4580                                                   __fy * _VSTD::exp(__fx + __e))
4581                    break;
4582            }
4583            else
4584            {
4585                if (__fy - __u * __fy <= __py * _VSTD::exp(__px - __fx))
4586                    break;
4587            }
4588        }
4589    }
4590    return __x;
4591}
4592
4593template <class _CharT, class _Traits, class _IntType>
4594basic_ostream<_CharT, _Traits>&
4595operator<<(basic_ostream<_CharT, _Traits>& __os,
4596           const poisson_distribution<_IntType>& __x)
4597{
4598    __save_flags<_CharT, _Traits> _(__os);
4599    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4600               ios_base::scientific);
4601    return __os << __x.mean();
4602}
4603
4604template <class _CharT, class _Traits, class _IntType>
4605basic_istream<_CharT, _Traits>&
4606operator>>(basic_istream<_CharT, _Traits>& __is,
4607           poisson_distribution<_IntType>& __x)
4608{
4609    typedef poisson_distribution<_IntType> _Eng;
4610    typedef typename _Eng::param_type param_type;
4611    __save_flags<_CharT, _Traits> _(__is);
4612    __is.flags(ios_base::dec | ios_base::skipws);
4613    double __mean;
4614    __is >> __mean;
4615    if (!__is.fail())
4616        __x.param(param_type(__mean));
4617    return __is;
4618}
4619
4620// weibull_distribution
4621
4622template<class _RealType = double>
4623class _LIBCPP_VISIBLE weibull_distribution
4624{
4625public:
4626    // types
4627    typedef _RealType result_type;
4628
4629    class _LIBCPP_VISIBLE param_type
4630    {
4631        result_type __a_;
4632        result_type __b_;
4633    public:
4634        typedef weibull_distribution distribution_type;
4635
4636        _LIBCPP_INLINE_VISIBILITY
4637        explicit param_type(result_type __a = 1, result_type __b = 1)
4638            : __a_(__a), __b_(__b) {}
4639
4640        _LIBCPP_INLINE_VISIBILITY
4641        result_type a() const {return __a_;}
4642        _LIBCPP_INLINE_VISIBILITY
4643        result_type b() const {return __b_;}
4644
4645        friend _LIBCPP_INLINE_VISIBILITY
4646            bool operator==(const param_type& __x, const param_type& __y)
4647            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
4648        friend _LIBCPP_INLINE_VISIBILITY
4649            bool operator!=(const param_type& __x, const param_type& __y)
4650            {return !(__x == __y);}
4651    };
4652
4653private:
4654    param_type __p_;
4655
4656public:
4657    // constructor and reset functions
4658    _LIBCPP_INLINE_VISIBILITY
4659    explicit weibull_distribution(result_type __a = 1, result_type __b = 1)
4660        : __p_(param_type(__a, __b)) {}
4661    _LIBCPP_INLINE_VISIBILITY
4662    explicit weibull_distribution(const param_type& __p)
4663        : __p_(__p) {}
4664    _LIBCPP_INLINE_VISIBILITY
4665    void reset() {}
4666
4667    // generating functions
4668    template<class _URNG>
4669        _LIBCPP_INLINE_VISIBILITY
4670        result_type operator()(_URNG& __g)
4671        {return (*this)(__g, __p_);}
4672    template<class _URNG>
4673        _LIBCPP_INLINE_VISIBILITY
4674        result_type operator()(_URNG& __g, const param_type& __p)
4675        {return __p.b() *
4676            _VSTD::pow(exponential_distribution<result_type>()(__g), 1/__p.a());}
4677
4678    // property functions
4679    _LIBCPP_INLINE_VISIBILITY
4680    result_type a() const {return __p_.a();}
4681    _LIBCPP_INLINE_VISIBILITY
4682    result_type b() const {return __p_.b();}
4683
4684    _LIBCPP_INLINE_VISIBILITY
4685    param_type param() const {return __p_;}
4686    _LIBCPP_INLINE_VISIBILITY
4687    void param(const param_type& __p) {__p_ = __p;}
4688
4689    _LIBCPP_INLINE_VISIBILITY
4690    result_type min() const {return 0;}
4691    _LIBCPP_INLINE_VISIBILITY
4692    result_type max() const {return numeric_limits<result_type>::infinity();}
4693
4694    friend _LIBCPP_INLINE_VISIBILITY
4695        bool operator==(const weibull_distribution& __x,
4696                        const weibull_distribution& __y)
4697        {return __x.__p_ == __y.__p_;}
4698    friend _LIBCPP_INLINE_VISIBILITY
4699        bool operator!=(const weibull_distribution& __x,
4700                        const weibull_distribution& __y)
4701        {return !(__x == __y);}
4702};
4703
4704template <class _CharT, class _Traits, class _RT>
4705basic_ostream<_CharT, _Traits>&
4706operator<<(basic_ostream<_CharT, _Traits>& __os,
4707           const weibull_distribution<_RT>& __x)
4708{
4709    __save_flags<_CharT, _Traits> _(__os);
4710    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4711               ios_base::scientific);
4712    _CharT __sp = __os.widen(' ');
4713    __os.fill(__sp);
4714    __os << __x.a() << __sp << __x.b();
4715    return __os;
4716}
4717
4718template <class _CharT, class _Traits, class _RT>
4719basic_istream<_CharT, _Traits>&
4720operator>>(basic_istream<_CharT, _Traits>& __is,
4721           weibull_distribution<_RT>& __x)
4722{
4723    typedef weibull_distribution<_RT> _Eng;
4724    typedef typename _Eng::result_type result_type;
4725    typedef typename _Eng::param_type param_type;
4726    __save_flags<_CharT, _Traits> _(__is);
4727    __is.flags(ios_base::dec | ios_base::skipws);
4728    result_type __a;
4729    result_type __b;
4730    __is >> __a >> __b;
4731    if (!__is.fail())
4732        __x.param(param_type(__a, __b));
4733    return __is;
4734}
4735
4736template<class _RealType = double>
4737class _LIBCPP_VISIBLE extreme_value_distribution
4738{
4739public:
4740    // types
4741    typedef _RealType result_type;
4742
4743    class _LIBCPP_VISIBLE param_type
4744    {
4745        result_type __a_;
4746        result_type __b_;
4747    public:
4748        typedef extreme_value_distribution distribution_type;
4749
4750        _LIBCPP_INLINE_VISIBILITY
4751        explicit param_type(result_type __a = 0, result_type __b = 1)
4752            : __a_(__a), __b_(__b) {}
4753
4754        _LIBCPP_INLINE_VISIBILITY
4755        result_type a() const {return __a_;}
4756        _LIBCPP_INLINE_VISIBILITY
4757        result_type b() const {return __b_;}
4758
4759        friend _LIBCPP_INLINE_VISIBILITY
4760            bool operator==(const param_type& __x, const param_type& __y)
4761            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
4762        friend _LIBCPP_INLINE_VISIBILITY
4763            bool operator!=(const param_type& __x, const param_type& __y)
4764            {return !(__x == __y);}
4765    };
4766
4767private:
4768    param_type __p_;
4769
4770public:
4771    // constructor and reset functions
4772    _LIBCPP_INLINE_VISIBILITY
4773    explicit extreme_value_distribution(result_type __a = 0, result_type __b = 1)
4774        : __p_(param_type(__a, __b)) {}
4775    _LIBCPP_INLINE_VISIBILITY
4776    explicit extreme_value_distribution(const param_type& __p)
4777        : __p_(__p) {}
4778    _LIBCPP_INLINE_VISIBILITY
4779    void reset() {}
4780
4781    // generating functions
4782    template<class _URNG>
4783        _LIBCPP_INLINE_VISIBILITY
4784        result_type operator()(_URNG& __g)
4785        {return (*this)(__g, __p_);}
4786    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4787
4788    // property functions
4789    _LIBCPP_INLINE_VISIBILITY
4790    result_type a() const {return __p_.a();}
4791    _LIBCPP_INLINE_VISIBILITY
4792    result_type b() const {return __p_.b();}
4793
4794    _LIBCPP_INLINE_VISIBILITY
4795    param_type param() const {return __p_;}
4796    _LIBCPP_INLINE_VISIBILITY
4797    void param(const param_type& __p) {__p_ = __p;}
4798
4799    _LIBCPP_INLINE_VISIBILITY
4800    result_type min() const {return -numeric_limits<result_type>::infinity();}
4801    _LIBCPP_INLINE_VISIBILITY
4802    result_type max() const {return numeric_limits<result_type>::infinity();}
4803
4804    friend _LIBCPP_INLINE_VISIBILITY
4805        bool operator==(const extreme_value_distribution& __x,
4806                        const extreme_value_distribution& __y)
4807        {return __x.__p_ == __y.__p_;}
4808    friend _LIBCPP_INLINE_VISIBILITY
4809        bool operator!=(const extreme_value_distribution& __x,
4810                        const extreme_value_distribution& __y)
4811        {return !(__x == __y);}
4812};
4813
4814template<class _RealType>
4815template<class _URNG>
4816_RealType
4817extreme_value_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4818{
4819    return __p.a() - __p.b() *
4820         _VSTD::log(-_VSTD::log(1-uniform_real_distribution<result_type>()(__g)));
4821}
4822
4823template <class _CharT, class _Traits, class _RT>
4824basic_ostream<_CharT, _Traits>&
4825operator<<(basic_ostream<_CharT, _Traits>& __os,
4826           const extreme_value_distribution<_RT>& __x)
4827{
4828    __save_flags<_CharT, _Traits> _(__os);
4829    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4830               ios_base::scientific);
4831    _CharT __sp = __os.widen(' ');
4832    __os.fill(__sp);
4833    __os << __x.a() << __sp << __x.b();
4834    return __os;
4835}
4836
4837template <class _CharT, class _Traits, class _RT>
4838basic_istream<_CharT, _Traits>&
4839operator>>(basic_istream<_CharT, _Traits>& __is,
4840           extreme_value_distribution<_RT>& __x)
4841{
4842    typedef extreme_value_distribution<_RT> _Eng;
4843    typedef typename _Eng::result_type result_type;
4844    typedef typename _Eng::param_type param_type;
4845    __save_flags<_CharT, _Traits> _(__is);
4846    __is.flags(ios_base::dec | ios_base::skipws);
4847    result_type __a;
4848    result_type __b;
4849    __is >> __a >> __b;
4850    if (!__is.fail())
4851        __x.param(param_type(__a, __b));
4852    return __is;
4853}
4854
4855// gamma_distribution
4856
4857template<class _RealType = double>
4858class _LIBCPP_VISIBLE gamma_distribution
4859{
4860public:
4861    // types
4862    typedef _RealType result_type;
4863
4864    class _LIBCPP_VISIBLE param_type
4865    {
4866        result_type __alpha_;
4867        result_type __beta_;
4868    public:
4869        typedef gamma_distribution distribution_type;
4870
4871        _LIBCPP_INLINE_VISIBILITY
4872        explicit param_type(result_type __alpha = 1, result_type __beta = 1)
4873            : __alpha_(__alpha), __beta_(__beta) {}
4874
4875        _LIBCPP_INLINE_VISIBILITY
4876        result_type alpha() const {return __alpha_;}
4877        _LIBCPP_INLINE_VISIBILITY
4878        result_type beta() const {return __beta_;}
4879
4880        friend _LIBCPP_INLINE_VISIBILITY
4881            bool operator==(const param_type& __x, const param_type& __y)
4882            {return __x.__alpha_ == __y.__alpha_ && __x.__beta_ == __y.__beta_;}
4883        friend _LIBCPP_INLINE_VISIBILITY
4884            bool operator!=(const param_type& __x, const param_type& __y)
4885            {return !(__x == __y);}
4886    };
4887
4888private:
4889    param_type __p_;
4890
4891public:
4892    // constructors and reset functions
4893    _LIBCPP_INLINE_VISIBILITY
4894    explicit gamma_distribution(result_type __alpha = 1, result_type __beta = 1)
4895        : __p_(param_type(__alpha, __beta)) {}
4896    _LIBCPP_INLINE_VISIBILITY
4897    explicit gamma_distribution(const param_type& __p)
4898        : __p_(__p) {}
4899    _LIBCPP_INLINE_VISIBILITY
4900    void reset() {}
4901
4902    // generating functions
4903    template<class _URNG>
4904        _LIBCPP_INLINE_VISIBILITY
4905        result_type operator()(_URNG& __g)
4906        {return (*this)(__g, __p_);}
4907    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4908
4909    // property functions
4910    _LIBCPP_INLINE_VISIBILITY
4911    result_type alpha() const {return __p_.alpha();}
4912    _LIBCPP_INLINE_VISIBILITY
4913    result_type beta() const {return __p_.beta();}
4914
4915    _LIBCPP_INLINE_VISIBILITY
4916    param_type param() const {return __p_;}
4917    _LIBCPP_INLINE_VISIBILITY
4918    void param(const param_type& __p) {__p_ = __p;}
4919
4920    _LIBCPP_INLINE_VISIBILITY
4921    result_type min() const {return 0;}
4922    _LIBCPP_INLINE_VISIBILITY
4923    result_type max() const {return numeric_limits<result_type>::infinity();}
4924
4925    friend _LIBCPP_INLINE_VISIBILITY
4926        bool operator==(const gamma_distribution& __x,
4927                        const gamma_distribution& __y)
4928        {return __x.__p_ == __y.__p_;}
4929    friend _LIBCPP_INLINE_VISIBILITY
4930        bool operator!=(const gamma_distribution& __x,
4931                        const gamma_distribution& __y)
4932        {return !(__x == __y);}
4933};
4934
4935template <class _RealType>
4936template<class _URNG>
4937_RealType
4938gamma_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4939{
4940    result_type __a = __p.alpha();
4941    uniform_real_distribution<result_type> __gen(0, 1);
4942    exponential_distribution<result_type> __egen;
4943    result_type __x;
4944    if (__a == 1)
4945        __x = __egen(__g);
4946    else if (__a > 1)
4947    {
4948        const result_type __b = __a - 1;
4949        const result_type __c = 3 * __a - result_type(0.75);
4950        while (true)
4951        {
4952            const result_type __u = __gen(__g);
4953            const result_type __v = __gen(__g);
4954            const result_type __w = __u * (1 - __u);
4955            if (__w != 0)
4956            {
4957                const result_type __y = _VSTD::sqrt(__c / __w) *
4958                                        (__u - result_type(0.5));
4959                __x = __b + __y;
4960                if (__x >= 0)
4961                {
4962                    const result_type __z = 64 * __w * __w * __w * __v * __v;
4963                    if (__z <= 1 - 2 * __y * __y / __x)
4964                        break;
4965                    if (_VSTD::log(__z) <= 2 * (__b * _VSTD::log(__x / __b) - __y))
4966                        break;
4967                }
4968            }
4969        }
4970    }
4971    else  // __a < 1
4972    {
4973        while (true)
4974        {
4975            const result_type __u = __gen(__g);
4976            const result_type __es = __egen(__g);
4977            if (__u <= 1 - __a)
4978            {
4979                __x = _VSTD::pow(__u, 1 / __a);
4980                if (__x <= __es)
4981                    break;
4982            }
4983            else
4984            {
4985                const result_type __e = -_VSTD::log((1-__u)/__a);
4986                __x = _VSTD::pow(1 - __a + __a * __e, 1 / __a);
4987                if (__x <= __e + __es)
4988                    break;
4989            }
4990        }
4991    }
4992    return __x * __p.beta();
4993}
4994
4995template <class _CharT, class _Traits, class _RT>
4996basic_ostream<_CharT, _Traits>&
4997operator<<(basic_ostream<_CharT, _Traits>& __os,
4998           const gamma_distribution<_RT>& __x)
4999{
5000    __save_flags<_CharT, _Traits> _(__os);
5001    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5002               ios_base::scientific);
5003    _CharT __sp = __os.widen(' ');
5004    __os.fill(__sp);
5005    __os << __x.alpha() << __sp << __x.beta();
5006    return __os;
5007}
5008
5009template <class _CharT, class _Traits, class _RT>
5010basic_istream<_CharT, _Traits>&
5011operator>>(basic_istream<_CharT, _Traits>& __is,
5012           gamma_distribution<_RT>& __x)
5013{
5014    typedef gamma_distribution<_RT> _Eng;
5015    typedef typename _Eng::result_type result_type;
5016    typedef typename _Eng::param_type param_type;
5017    __save_flags<_CharT, _Traits> _(__is);
5018    __is.flags(ios_base::dec | ios_base::skipws);
5019    result_type __alpha;
5020    result_type __beta;
5021    __is >> __alpha >> __beta;
5022    if (!__is.fail())
5023        __x.param(param_type(__alpha, __beta));
5024    return __is;
5025}
5026
5027// negative_binomial_distribution
5028
5029template<class _IntType = int>
5030class _LIBCPP_VISIBLE negative_binomial_distribution
5031{
5032public:
5033    // types
5034    typedef _IntType result_type;
5035
5036    class _LIBCPP_VISIBLE param_type
5037    {
5038        result_type __k_;
5039        double __p_;
5040    public:
5041        typedef negative_binomial_distribution distribution_type;
5042
5043        _LIBCPP_INLINE_VISIBILITY
5044        explicit param_type(result_type __k = 1, double __p = 0.5)
5045            : __k_(__k), __p_(__p) {}
5046
5047        _LIBCPP_INLINE_VISIBILITY
5048        result_type k() const {return __k_;}
5049        _LIBCPP_INLINE_VISIBILITY
5050        double p() const {return __p_;}
5051
5052        friend _LIBCPP_INLINE_VISIBILITY
5053            bool operator==(const param_type& __x, const param_type& __y)
5054            {return __x.__k_ == __y.__k_ && __x.__p_ == __y.__p_;}
5055        friend _LIBCPP_INLINE_VISIBILITY
5056            bool operator!=(const param_type& __x, const param_type& __y)
5057            {return !(__x == __y);}
5058    };
5059
5060private:
5061    param_type __p_;
5062
5063public:
5064    // constructor and reset functions
5065    _LIBCPP_INLINE_VISIBILITY
5066    explicit negative_binomial_distribution(result_type __k = 1, double __p = 0.5)
5067        : __p_(__k, __p) {}
5068    _LIBCPP_INLINE_VISIBILITY
5069    explicit negative_binomial_distribution(const param_type& __p) : __p_(__p) {}
5070    _LIBCPP_INLINE_VISIBILITY
5071    void reset() {}
5072
5073    // generating functions
5074    template<class _URNG>
5075        _LIBCPP_INLINE_VISIBILITY
5076        result_type operator()(_URNG& __g)
5077        {return (*this)(__g, __p_);}
5078    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5079
5080    // property functions
5081    _LIBCPP_INLINE_VISIBILITY
5082    result_type k() const {return __p_.k();}
5083    _LIBCPP_INLINE_VISIBILITY
5084    double p() const {return __p_.p();}
5085
5086    _LIBCPP_INLINE_VISIBILITY
5087    param_type param() const {return __p_;}
5088    _LIBCPP_INLINE_VISIBILITY
5089    void param(const param_type& __p) {__p_ = __p;}
5090
5091    _LIBCPP_INLINE_VISIBILITY
5092    result_type min() const {return 0;}
5093    _LIBCPP_INLINE_VISIBILITY
5094    result_type max() const {return numeric_limits<result_type>::max();}
5095
5096    friend _LIBCPP_INLINE_VISIBILITY
5097        bool operator==(const negative_binomial_distribution& __x,
5098                        const negative_binomial_distribution& __y)
5099        {return __x.__p_ == __y.__p_;}
5100    friend _LIBCPP_INLINE_VISIBILITY
5101        bool operator!=(const negative_binomial_distribution& __x,
5102                        const negative_binomial_distribution& __y)
5103        {return !(__x == __y);}
5104};
5105
5106template <class _IntType>
5107template<class _URNG>
5108_IntType
5109negative_binomial_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
5110{
5111    result_type __k = __pr.k();
5112    double __p = __pr.p();
5113    if (__k <= 21 * __p)
5114    {
5115        bernoulli_distribution __gen(__p);
5116        result_type __f = 0;
5117        result_type __s = 0;
5118        while (__s < __k)
5119        {
5120            if (__gen(__urng))
5121                ++__s;
5122            else
5123                ++__f;
5124        }
5125        return __f;
5126    }
5127    return poisson_distribution<result_type>(gamma_distribution<double>
5128                                            (__k, (1-__p)/__p)(__urng))(__urng);
5129}
5130
5131template <class _CharT, class _Traits, class _IntType>
5132basic_ostream<_CharT, _Traits>&
5133operator<<(basic_ostream<_CharT, _Traits>& __os,
5134           const negative_binomial_distribution<_IntType>& __x)
5135{
5136    __save_flags<_CharT, _Traits> _(__os);
5137    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5138               ios_base::scientific);
5139    _CharT __sp = __os.widen(' ');
5140    __os.fill(__sp);
5141    return __os << __x.k() << __sp << __x.p();
5142}
5143
5144template <class _CharT, class _Traits, class _IntType>
5145basic_istream<_CharT, _Traits>&
5146operator>>(basic_istream<_CharT, _Traits>& __is,
5147           negative_binomial_distribution<_IntType>& __x)
5148{
5149    typedef negative_binomial_distribution<_IntType> _Eng;
5150    typedef typename _Eng::result_type result_type;
5151    typedef typename _Eng::param_type param_type;
5152    __save_flags<_CharT, _Traits> _(__is);
5153    __is.flags(ios_base::dec | ios_base::skipws);
5154    result_type __k;
5155    double __p;
5156    __is >> __k >> __p;
5157    if (!__is.fail())
5158        __x.param(param_type(__k, __p));
5159    return __is;
5160}
5161
5162// geometric_distribution
5163
5164template<class _IntType = int>
5165class _LIBCPP_VISIBLE geometric_distribution
5166{
5167public:
5168    // types
5169    typedef _IntType result_type;
5170
5171    class _LIBCPP_VISIBLE param_type
5172    {
5173        double __p_;
5174    public:
5175        typedef geometric_distribution distribution_type;
5176
5177        _LIBCPP_INLINE_VISIBILITY
5178        explicit param_type(double __p = 0.5) : __p_(__p) {}
5179
5180        _LIBCPP_INLINE_VISIBILITY
5181        double p() const {return __p_;}
5182
5183        friend _LIBCPP_INLINE_VISIBILITY
5184            bool operator==(const param_type& __x, const param_type& __y)
5185            {return __x.__p_ == __y.__p_;}
5186        friend _LIBCPP_INLINE_VISIBILITY
5187            bool operator!=(const param_type& __x, const param_type& __y)
5188            {return !(__x == __y);}
5189    };
5190
5191private:
5192    param_type __p_;
5193
5194public:
5195    // constructors and reset functions
5196    _LIBCPP_INLINE_VISIBILITY
5197    explicit geometric_distribution(double __p = 0.5) : __p_(__p) {}
5198    _LIBCPP_INLINE_VISIBILITY
5199    explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
5200    _LIBCPP_INLINE_VISIBILITY
5201    void reset() {}
5202
5203    // generating functions
5204    template<class _URNG>
5205        _LIBCPP_INLINE_VISIBILITY
5206        result_type operator()(_URNG& __g)
5207        {return (*this)(__g, __p_);}
5208    template<class _URNG>
5209        _LIBCPP_INLINE_VISIBILITY
5210        result_type operator()(_URNG& __g, const param_type& __p)
5211        {return negative_binomial_distribution<result_type>(1, __p.p())(__g);}
5212
5213    // property functions
5214    _LIBCPP_INLINE_VISIBILITY
5215    double p() const {return __p_.p();}
5216
5217    _LIBCPP_INLINE_VISIBILITY
5218    param_type param() const {return __p_;}
5219    _LIBCPP_INLINE_VISIBILITY
5220    void param(const param_type& __p) {__p_ = __p;}
5221
5222    _LIBCPP_INLINE_VISIBILITY
5223    result_type min() const {return 0;}
5224    _LIBCPP_INLINE_VISIBILITY
5225    result_type max() const {return numeric_limits<result_type>::max();}
5226
5227    friend _LIBCPP_INLINE_VISIBILITY
5228        bool operator==(const geometric_distribution& __x,
5229                        const geometric_distribution& __y)
5230        {return __x.__p_ == __y.__p_;}
5231    friend _LIBCPP_INLINE_VISIBILITY
5232        bool operator!=(const geometric_distribution& __x,
5233                        const geometric_distribution& __y)
5234        {return !(__x == __y);}
5235};
5236
5237template <class _CharT, class _Traits, class _IntType>
5238basic_ostream<_CharT, _Traits>&
5239operator<<(basic_ostream<_CharT, _Traits>& __os,
5240           const geometric_distribution<_IntType>& __x)
5241{
5242    __save_flags<_CharT, _Traits> _(__os);
5243    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5244               ios_base::scientific);
5245    return __os << __x.p();
5246}
5247
5248template <class _CharT, class _Traits, class _IntType>
5249basic_istream<_CharT, _Traits>&
5250operator>>(basic_istream<_CharT, _Traits>& __is,
5251           geometric_distribution<_IntType>& __x)
5252{
5253    typedef geometric_distribution<_IntType> _Eng;
5254    typedef typename _Eng::param_type param_type;
5255    __save_flags<_CharT, _Traits> _(__is);
5256    __is.flags(ios_base::dec | ios_base::skipws);
5257    double __p;
5258    __is >> __p;
5259    if (!__is.fail())
5260        __x.param(param_type(__p));
5261    return __is;
5262}
5263
5264// chi_squared_distribution
5265
5266template<class _RealType = double>
5267class _LIBCPP_VISIBLE chi_squared_distribution
5268{
5269public:
5270    // types
5271    typedef _RealType result_type;
5272
5273    class _LIBCPP_VISIBLE param_type
5274    {
5275        result_type __n_;
5276    public:
5277        typedef chi_squared_distribution distribution_type;
5278
5279        _LIBCPP_INLINE_VISIBILITY
5280        explicit param_type(result_type __n = 1) : __n_(__n) {}
5281
5282        _LIBCPP_INLINE_VISIBILITY
5283        result_type n() const {return __n_;}
5284
5285        friend _LIBCPP_INLINE_VISIBILITY
5286            bool operator==(const param_type& __x, const param_type& __y)
5287            {return __x.__n_ == __y.__n_;}
5288        friend _LIBCPP_INLINE_VISIBILITY
5289            bool operator!=(const param_type& __x, const param_type& __y)
5290            {return !(__x == __y);}
5291    };
5292
5293private:
5294    param_type __p_;
5295
5296public:
5297    // constructor and reset functions
5298    _LIBCPP_INLINE_VISIBILITY
5299    explicit chi_squared_distribution(result_type __n = 1)
5300        : __p_(param_type(__n)) {}
5301    _LIBCPP_INLINE_VISIBILITY
5302    explicit chi_squared_distribution(const param_type& __p)
5303        : __p_(__p) {}
5304    _LIBCPP_INLINE_VISIBILITY
5305    void reset() {}
5306
5307    // generating functions
5308    template<class _URNG>
5309        _LIBCPP_INLINE_VISIBILITY
5310        result_type operator()(_URNG& __g)
5311        {return (*this)(__g, __p_);}
5312    template<class _URNG>
5313        _LIBCPP_INLINE_VISIBILITY
5314        result_type operator()(_URNG& __g, const param_type& __p)
5315        {return gamma_distribution<result_type>(__p.n() / 2, 2)(__g);}
5316
5317    // property functions
5318    _LIBCPP_INLINE_VISIBILITY
5319    result_type n() const {return __p_.n();}
5320
5321    _LIBCPP_INLINE_VISIBILITY
5322    param_type param() const {return __p_;}
5323    _LIBCPP_INLINE_VISIBILITY
5324    void param(const param_type& __p) {__p_ = __p;}
5325
5326    _LIBCPP_INLINE_VISIBILITY
5327    result_type min() const {return 0;}
5328    _LIBCPP_INLINE_VISIBILITY
5329    result_type max() const {return numeric_limits<result_type>::infinity();}
5330
5331    friend _LIBCPP_INLINE_VISIBILITY
5332        bool operator==(const chi_squared_distribution& __x,
5333                        const chi_squared_distribution& __y)
5334        {return __x.__p_ == __y.__p_;}
5335    friend _LIBCPP_INLINE_VISIBILITY
5336        bool operator!=(const chi_squared_distribution& __x,
5337                        const chi_squared_distribution& __y)
5338        {return !(__x == __y);}
5339};
5340
5341template <class _CharT, class _Traits, class _RT>
5342basic_ostream<_CharT, _Traits>&
5343operator<<(basic_ostream<_CharT, _Traits>& __os,
5344           const chi_squared_distribution<_RT>& __x)
5345{
5346    __save_flags<_CharT, _Traits> _(__os);
5347    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5348               ios_base::scientific);
5349    __os << __x.n();
5350    return __os;
5351}
5352
5353template <class _CharT, class _Traits, class _RT>
5354basic_istream<_CharT, _Traits>&
5355operator>>(basic_istream<_CharT, _Traits>& __is,
5356           chi_squared_distribution<_RT>& __x)
5357{
5358    typedef chi_squared_distribution<_RT> _Eng;
5359    typedef typename _Eng::result_type result_type;
5360    typedef typename _Eng::param_type param_type;
5361    __save_flags<_CharT, _Traits> _(__is);
5362    __is.flags(ios_base::dec | ios_base::skipws);
5363    result_type __n;
5364    __is >> __n;
5365    if (!__is.fail())
5366        __x.param(param_type(__n));
5367    return __is;
5368}
5369
5370// cauchy_distribution
5371
5372template<class _RealType = double>
5373class _LIBCPP_VISIBLE cauchy_distribution
5374{
5375public:
5376    // types
5377    typedef _RealType result_type;
5378
5379    class _LIBCPP_VISIBLE param_type
5380    {
5381        result_type __a_;
5382        result_type __b_;
5383    public:
5384        typedef cauchy_distribution distribution_type;
5385
5386        _LIBCPP_INLINE_VISIBILITY
5387        explicit param_type(result_type __a = 0, result_type __b = 1)
5388            : __a_(__a), __b_(__b) {}
5389
5390        _LIBCPP_INLINE_VISIBILITY
5391        result_type a() const {return __a_;}
5392        _LIBCPP_INLINE_VISIBILITY
5393        result_type b() const {return __b_;}
5394
5395        friend _LIBCPP_INLINE_VISIBILITY
5396            bool operator==(const param_type& __x, const param_type& __y)
5397            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
5398        friend _LIBCPP_INLINE_VISIBILITY
5399            bool operator!=(const param_type& __x, const param_type& __y)
5400            {return !(__x == __y);}
5401    };
5402
5403private:
5404    param_type __p_;
5405
5406public:
5407    // constructor and reset functions
5408    _LIBCPP_INLINE_VISIBILITY
5409    explicit cauchy_distribution(result_type __a = 0, result_type __b = 1)
5410        : __p_(param_type(__a, __b)) {}
5411    _LIBCPP_INLINE_VISIBILITY
5412    explicit cauchy_distribution(const param_type& __p)
5413        : __p_(__p) {}
5414    _LIBCPP_INLINE_VISIBILITY
5415    void reset() {}
5416
5417    // generating functions
5418    template<class _URNG>
5419        _LIBCPP_INLINE_VISIBILITY
5420        result_type operator()(_URNG& __g)
5421        {return (*this)(__g, __p_);}
5422    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5423
5424    // property functions
5425    _LIBCPP_INLINE_VISIBILITY
5426    result_type a() const {return __p_.a();}
5427    _LIBCPP_INLINE_VISIBILITY
5428    result_type b() const {return __p_.b();}
5429
5430    _LIBCPP_INLINE_VISIBILITY
5431    param_type param() const {return __p_;}
5432    _LIBCPP_INLINE_VISIBILITY
5433    void param(const param_type& __p) {__p_ = __p;}
5434
5435    _LIBCPP_INLINE_VISIBILITY
5436    result_type min() const {return -numeric_limits<result_type>::infinity();}
5437    _LIBCPP_INLINE_VISIBILITY
5438    result_type max() const {return numeric_limits<result_type>::infinity();}
5439
5440    friend _LIBCPP_INLINE_VISIBILITY
5441        bool operator==(const cauchy_distribution& __x,
5442                        const cauchy_distribution& __y)
5443        {return __x.__p_ == __y.__p_;}
5444    friend _LIBCPP_INLINE_VISIBILITY
5445        bool operator!=(const cauchy_distribution& __x,
5446                        const cauchy_distribution& __y)
5447        {return !(__x == __y);}
5448};
5449
5450template <class _RealType>
5451template<class _URNG>
5452inline _LIBCPP_INLINE_VISIBILITY
5453_RealType
5454cauchy_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5455{
5456    uniform_real_distribution<result_type> __gen;
5457    // purposefully let tan arg get as close to pi/2 as it wants, tan will return a finite
5458    return __p.a() + __p.b() * _VSTD::tan(3.1415926535897932384626433832795 * __gen(__g));
5459}
5460
5461template <class _CharT, class _Traits, class _RT>
5462basic_ostream<_CharT, _Traits>&
5463operator<<(basic_ostream<_CharT, _Traits>& __os,
5464           const cauchy_distribution<_RT>& __x)
5465{
5466    __save_flags<_CharT, _Traits> _(__os);
5467    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5468               ios_base::scientific);
5469    _CharT __sp = __os.widen(' ');
5470    __os.fill(__sp);
5471    __os << __x.a() << __sp << __x.b();
5472    return __os;
5473}
5474
5475template <class _CharT, class _Traits, class _RT>
5476basic_istream<_CharT, _Traits>&
5477operator>>(basic_istream<_CharT, _Traits>& __is,
5478           cauchy_distribution<_RT>& __x)
5479{
5480    typedef cauchy_distribution<_RT> _Eng;
5481    typedef typename _Eng::result_type result_type;
5482    typedef typename _Eng::param_type param_type;
5483    __save_flags<_CharT, _Traits> _(__is);
5484    __is.flags(ios_base::dec | ios_base::skipws);
5485    result_type __a;
5486    result_type __b;
5487    __is >> __a >> __b;
5488    if (!__is.fail())
5489        __x.param(param_type(__a, __b));
5490    return __is;
5491}
5492
5493// fisher_f_distribution
5494
5495template<class _RealType = double>
5496class _LIBCPP_VISIBLE fisher_f_distribution
5497{
5498public:
5499    // types
5500    typedef _RealType result_type;
5501
5502    class _LIBCPP_VISIBLE param_type
5503    {
5504        result_type __m_;
5505        result_type __n_;
5506    public:
5507        typedef fisher_f_distribution distribution_type;
5508
5509        _LIBCPP_INLINE_VISIBILITY
5510        explicit param_type(result_type __m = 1, result_type __n = 1)
5511            : __m_(__m), __n_(__n) {}
5512
5513        _LIBCPP_INLINE_VISIBILITY
5514        result_type m() const {return __m_;}
5515        _LIBCPP_INLINE_VISIBILITY
5516        result_type n() const {return __n_;}
5517
5518        friend _LIBCPP_INLINE_VISIBILITY
5519            bool operator==(const param_type& __x, const param_type& __y)
5520            {return __x.__m_ == __y.__m_ && __x.__n_ == __y.__n_;}
5521        friend _LIBCPP_INLINE_VISIBILITY
5522            bool operator!=(const param_type& __x, const param_type& __y)
5523            {return !(__x == __y);}
5524    };
5525
5526private:
5527    param_type __p_;
5528
5529public:
5530    // constructor and reset functions
5531    _LIBCPP_INLINE_VISIBILITY
5532    explicit fisher_f_distribution(result_type __m = 1, result_type __n = 1)
5533        : __p_(param_type(__m, __n)) {}
5534    _LIBCPP_INLINE_VISIBILITY
5535    explicit fisher_f_distribution(const param_type& __p)
5536        : __p_(__p) {}
5537    _LIBCPP_INLINE_VISIBILITY
5538    void reset() {}
5539
5540    // generating functions
5541    template<class _URNG>
5542        _LIBCPP_INLINE_VISIBILITY
5543        result_type operator()(_URNG& __g)
5544        {return (*this)(__g, __p_);}
5545    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5546
5547    // property functions
5548    _LIBCPP_INLINE_VISIBILITY
5549    result_type m() const {return __p_.m();}
5550    _LIBCPP_INLINE_VISIBILITY
5551    result_type n() const {return __p_.n();}
5552
5553    _LIBCPP_INLINE_VISIBILITY
5554    param_type param() const {return __p_;}
5555    _LIBCPP_INLINE_VISIBILITY
5556    void param(const param_type& __p) {__p_ = __p;}
5557
5558    _LIBCPP_INLINE_VISIBILITY
5559    result_type min() const {return 0;}
5560    _LIBCPP_INLINE_VISIBILITY
5561    result_type max() const {return numeric_limits<result_type>::infinity();}
5562
5563    friend _LIBCPP_INLINE_VISIBILITY
5564        bool operator==(const fisher_f_distribution& __x,
5565                        const fisher_f_distribution& __y)
5566        {return __x.__p_ == __y.__p_;}
5567    friend _LIBCPP_INLINE_VISIBILITY
5568        bool operator!=(const fisher_f_distribution& __x,
5569                        const fisher_f_distribution& __y)
5570        {return !(__x == __y);}
5571};
5572
5573template <class _RealType>
5574template<class _URNG>
5575_RealType
5576fisher_f_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5577{
5578    gamma_distribution<result_type> __gdm(__p.m() * result_type(.5));
5579    gamma_distribution<result_type> __gdn(__p.n() * result_type(.5));
5580    return __p.n() * __gdm(__g) / (__p.m() * __gdn(__g));
5581}
5582
5583template <class _CharT, class _Traits, class _RT>
5584basic_ostream<_CharT, _Traits>&
5585operator<<(basic_ostream<_CharT, _Traits>& __os,
5586           const fisher_f_distribution<_RT>& __x)
5587{
5588    __save_flags<_CharT, _Traits> _(__os);
5589    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5590               ios_base::scientific);
5591    _CharT __sp = __os.widen(' ');
5592    __os.fill(__sp);
5593    __os << __x.m() << __sp << __x.n();
5594    return __os;
5595}
5596
5597template <class _CharT, class _Traits, class _RT>
5598basic_istream<_CharT, _Traits>&
5599operator>>(basic_istream<_CharT, _Traits>& __is,
5600           fisher_f_distribution<_RT>& __x)
5601{
5602    typedef fisher_f_distribution<_RT> _Eng;
5603    typedef typename _Eng::result_type result_type;
5604    typedef typename _Eng::param_type param_type;
5605    __save_flags<_CharT, _Traits> _(__is);
5606    __is.flags(ios_base::dec | ios_base::skipws);
5607    result_type __m;
5608    result_type __n;
5609    __is >> __m >> __n;
5610    if (!__is.fail())
5611        __x.param(param_type(__m, __n));
5612    return __is;
5613}
5614
5615// student_t_distribution
5616
5617template<class _RealType = double>
5618class _LIBCPP_VISIBLE student_t_distribution
5619{
5620public:
5621    // types
5622    typedef _RealType result_type;
5623
5624    class _LIBCPP_VISIBLE param_type
5625    {
5626        result_type __n_;
5627    public:
5628        typedef student_t_distribution distribution_type;
5629
5630        _LIBCPP_INLINE_VISIBILITY
5631        explicit param_type(result_type __n = 1) : __n_(__n) {}
5632
5633        _LIBCPP_INLINE_VISIBILITY
5634        result_type n() const {return __n_;}
5635
5636        friend _LIBCPP_INLINE_VISIBILITY
5637            bool operator==(const param_type& __x, const param_type& __y)
5638            {return __x.__n_ == __y.__n_;}
5639        friend _LIBCPP_INLINE_VISIBILITY
5640            bool operator!=(const param_type& __x, const param_type& __y)
5641            {return !(__x == __y);}
5642    };
5643
5644private:
5645    param_type __p_;
5646    normal_distribution<result_type> __nd_;
5647
5648public:
5649    // constructor and reset functions
5650    _LIBCPP_INLINE_VISIBILITY
5651    explicit student_t_distribution(result_type __n = 1)
5652        : __p_(param_type(__n)) {}
5653    _LIBCPP_INLINE_VISIBILITY
5654    explicit student_t_distribution(const param_type& __p)
5655        : __p_(__p) {}
5656    _LIBCPP_INLINE_VISIBILITY
5657    void reset() {__nd_.reset();}
5658
5659    // generating functions
5660    template<class _URNG>
5661        _LIBCPP_INLINE_VISIBILITY
5662        result_type operator()(_URNG& __g)
5663        {return (*this)(__g, __p_);}
5664    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5665
5666    // property functions
5667    _LIBCPP_INLINE_VISIBILITY
5668    result_type n() const {return __p_.n();}
5669
5670    _LIBCPP_INLINE_VISIBILITY
5671    param_type param() const {return __p_;}
5672    _LIBCPP_INLINE_VISIBILITY
5673    void param(const param_type& __p) {__p_ = __p;}
5674
5675    _LIBCPP_INLINE_VISIBILITY
5676    result_type min() const {return -numeric_limits<result_type>::infinity();}
5677    _LIBCPP_INLINE_VISIBILITY
5678    result_type max() const {return numeric_limits<result_type>::infinity();}
5679
5680    friend _LIBCPP_INLINE_VISIBILITY
5681        bool operator==(const student_t_distribution& __x,
5682                        const student_t_distribution& __y)
5683        {return __x.__p_ == __y.__p_;}
5684    friend _LIBCPP_INLINE_VISIBILITY
5685        bool operator!=(const student_t_distribution& __x,
5686                        const student_t_distribution& __y)
5687        {return !(__x == __y);}
5688};
5689
5690template <class _RealType>
5691template<class _URNG>
5692_RealType
5693student_t_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5694{
5695    gamma_distribution<result_type> __gd(__p.n() * .5, 2);
5696    return __nd_(__g) * _VSTD::sqrt(__p.n()/__gd(__g));
5697}
5698
5699template <class _CharT, class _Traits, class _RT>
5700basic_ostream<_CharT, _Traits>&
5701operator<<(basic_ostream<_CharT, _Traits>& __os,
5702           const student_t_distribution<_RT>& __x)
5703{
5704    __save_flags<_CharT, _Traits> _(__os);
5705    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5706               ios_base::scientific);
5707    __os << __x.n();
5708    return __os;
5709}
5710
5711template <class _CharT, class _Traits, class _RT>
5712basic_istream<_CharT, _Traits>&
5713operator>>(basic_istream<_CharT, _Traits>& __is,
5714           student_t_distribution<_RT>& __x)
5715{
5716    typedef student_t_distribution<_RT> _Eng;
5717    typedef typename _Eng::result_type result_type;
5718    typedef typename _Eng::param_type param_type;
5719    __save_flags<_CharT, _Traits> _(__is);
5720    __is.flags(ios_base::dec | ios_base::skipws);
5721    result_type __n;
5722    __is >> __n;
5723    if (!__is.fail())
5724        __x.param(param_type(__n));
5725    return __is;
5726}
5727
5728// discrete_distribution
5729
5730template<class _IntType = int>
5731class _LIBCPP_VISIBLE discrete_distribution
5732{
5733public:
5734    // types
5735    typedef _IntType result_type;
5736
5737    class _LIBCPP_VISIBLE param_type
5738    {
5739        vector<double> __p_;
5740    public:
5741        typedef discrete_distribution distribution_type;
5742
5743        _LIBCPP_INLINE_VISIBILITY
5744        param_type() {}
5745        template<class _InputIterator>
5746            _LIBCPP_INLINE_VISIBILITY
5747            param_type(_InputIterator __f, _InputIterator __l)
5748            : __p_(__f, __l) {__init();}
5749#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5750        _LIBCPP_INLINE_VISIBILITY
5751        param_type(initializer_list<double> __wl)
5752            : __p_(__wl.begin(), __wl.end()) {__init();}
5753#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5754        template<class _UnaryOperation>
5755            param_type(size_t __nw, double __xmin, double __xmax,
5756                       _UnaryOperation __fw);
5757
5758        vector<double> probabilities() const;
5759
5760        friend _LIBCPP_INLINE_VISIBILITY
5761            bool operator==(const param_type& __x, const param_type& __y)
5762            {return __x.__p_ == __y.__p_;}
5763        friend _LIBCPP_INLINE_VISIBILITY
5764            bool operator!=(const param_type& __x, const param_type& __y)
5765            {return !(__x == __y);}
5766
5767    private:
5768        void __init();
5769
5770        friend class discrete_distribution;
5771
5772        template <class _CharT, class _Traits, class _IT>
5773        friend
5774        basic_ostream<_CharT, _Traits>&
5775        operator<<(basic_ostream<_CharT, _Traits>& __os,
5776                   const discrete_distribution<_IT>& __x);
5777
5778        template <class _CharT, class _Traits, class _IT>
5779        friend
5780        basic_istream<_CharT, _Traits>&
5781        operator>>(basic_istream<_CharT, _Traits>& __is,
5782                   discrete_distribution<_IT>& __x);
5783    };
5784
5785private:
5786    param_type __p_;
5787
5788public:
5789    // constructor and reset functions
5790    _LIBCPP_INLINE_VISIBILITY
5791    discrete_distribution() {}
5792    template<class _InputIterator>
5793        _LIBCPP_INLINE_VISIBILITY
5794        discrete_distribution(_InputIterator __f, _InputIterator __l)
5795            : __p_(__f, __l) {}
5796#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5797    _LIBCPP_INLINE_VISIBILITY
5798    discrete_distribution(initializer_list<double> __wl)
5799        : __p_(__wl) {}
5800#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5801    template<class _UnaryOperation>
5802        _LIBCPP_INLINE_VISIBILITY
5803        discrete_distribution(size_t __nw, double __xmin, double __xmax,
5804                              _UnaryOperation __fw)
5805        : __p_(__nw, __xmin, __xmax, __fw) {}
5806    explicit discrete_distribution(const param_type& __p)
5807    _LIBCPP_INLINE_VISIBILITY
5808        : __p_(__p) {}
5809    _LIBCPP_INLINE_VISIBILITY
5810    void reset() {}
5811
5812    // generating functions
5813    template<class _URNG>
5814        _LIBCPP_INLINE_VISIBILITY
5815        result_type operator()(_URNG& __g)
5816        {return (*this)(__g, __p_);}
5817    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5818
5819    // property functions
5820    _LIBCPP_INLINE_VISIBILITY
5821    vector<double> probabilities() const {return __p_.probabilities();}
5822
5823    _LIBCPP_INLINE_VISIBILITY
5824    param_type param() const {return __p_;}
5825    _LIBCPP_INLINE_VISIBILITY
5826    void param(const param_type& __p) {__p_ = __p;}
5827
5828    _LIBCPP_INLINE_VISIBILITY
5829    result_type min() const {return 0;}
5830    _LIBCPP_INLINE_VISIBILITY
5831    result_type max() const {return __p_.__p_.size();}
5832
5833    friend _LIBCPP_INLINE_VISIBILITY
5834        bool operator==(const discrete_distribution& __x,
5835                        const discrete_distribution& __y)
5836        {return __x.__p_ == __y.__p_;}
5837    friend _LIBCPP_INLINE_VISIBILITY
5838        bool operator!=(const discrete_distribution& __x,
5839                        const discrete_distribution& __y)
5840        {return !(__x == __y);}
5841
5842    template <class _CharT, class _Traits, class _IT>
5843    friend
5844    basic_ostream<_CharT, _Traits>&
5845    operator<<(basic_ostream<_CharT, _Traits>& __os,
5846               const discrete_distribution<_IT>& __x);
5847
5848    template <class _CharT, class _Traits, class _IT>
5849    friend
5850    basic_istream<_CharT, _Traits>&
5851    operator>>(basic_istream<_CharT, _Traits>& __is,
5852               discrete_distribution<_IT>& __x);
5853};
5854
5855template<class _IntType>
5856template<class _UnaryOperation>
5857discrete_distribution<_IntType>::param_type::param_type(size_t __nw,
5858                                                        double __xmin,
5859                                                        double __xmax,
5860                                                        _UnaryOperation __fw)
5861{
5862    if (__nw > 1)
5863    {
5864        __p_.reserve(__nw - 1);
5865        double __d = (__xmax - __xmin) / __nw;
5866        double __d2 = __d / 2;
5867        for (size_t __k = 0; __k < __nw; ++__k)
5868            __p_.push_back(__fw(__xmin + __k * __d + __d2));
5869        __init();
5870    }
5871}
5872
5873template<class _IntType>
5874void
5875discrete_distribution<_IntType>::param_type::__init()
5876{
5877    if (!__p_.empty())
5878    {
5879        if (__p_.size() > 1)
5880        {
5881            double __s = _VSTD::accumulate(__p_.begin(), __p_.end(), 0.0);
5882            for (_VSTD::vector<double>::iterator __i = __p_.begin(), __e = __p_.end();
5883                                                                       __i < __e; ++__i)
5884                *__i /= __s;
5885            vector<double> __t(__p_.size() - 1);
5886            _VSTD::partial_sum(__p_.begin(), __p_.end() - 1, __t.begin());
5887            swap(__p_, __t);
5888        }
5889        else
5890        {
5891            __p_.clear();
5892            __p_.shrink_to_fit();
5893        }
5894    }
5895}
5896
5897template<class _IntType>
5898vector<double>
5899discrete_distribution<_IntType>::param_type::probabilities() const
5900{
5901    size_t __n = __p_.size();
5902    _VSTD::vector<double> __p(__n+1);
5903    _VSTD::adjacent_difference(__p_.begin(), __p_.end(), __p.begin());
5904    if (__n > 0)
5905        __p[__n] = 1 - __p_[__n-1];
5906    else
5907        __p[0] = 1;
5908    return __p;
5909}
5910
5911template<class _IntType>
5912template<class _URNG>
5913_IntType
5914discrete_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
5915{
5916    uniform_real_distribution<double> __gen;
5917    return static_cast<_IntType>(
5918           _VSTD::upper_bound(__p.__p_.begin(), __p.__p_.end(), __gen(__g)) -
5919                                                              __p.__p_.begin());
5920}
5921
5922template <class _CharT, class _Traits, class _IT>
5923basic_ostream<_CharT, _Traits>&
5924operator<<(basic_ostream<_CharT, _Traits>& __os,
5925           const discrete_distribution<_IT>& __x)
5926{
5927    __save_flags<_CharT, _Traits> _(__os);
5928    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5929               ios_base::scientific);
5930    _CharT __sp = __os.widen(' ');
5931    __os.fill(__sp);
5932    size_t __n = __x.__p_.__p_.size();
5933    __os << __n;
5934    for (size_t __i = 0; __i < __n; ++__i)
5935        __os << __sp << __x.__p_.__p_[__i];
5936    return __os;
5937}
5938
5939template <class _CharT, class _Traits, class _IT>
5940basic_istream<_CharT, _Traits>&
5941operator>>(basic_istream<_CharT, _Traits>& __is,
5942           discrete_distribution<_IT>& __x)
5943{
5944    typedef discrete_distribution<_IT> _Eng;
5945    typedef typename _Eng::result_type result_type;
5946    typedef typename _Eng::param_type param_type;
5947    __save_flags<_CharT, _Traits> _(__is);
5948    __is.flags(ios_base::dec | ios_base::skipws);
5949    size_t __n;
5950    __is >> __n;
5951    vector<double> __p(__n);
5952    for (size_t __i = 0; __i < __n; ++__i)
5953        __is >> __p[__i];
5954    if (!__is.fail())
5955        swap(__x.__p_.__p_, __p);
5956    return __is;
5957}
5958
5959// piecewise_constant_distribution
5960
5961template<class _RealType = double>
5962class _LIBCPP_VISIBLE piecewise_constant_distribution
5963{
5964public:
5965    // types
5966    typedef _RealType result_type;
5967
5968    class _LIBCPP_VISIBLE param_type
5969    {
5970        vector<result_type> __b_;
5971        vector<result_type> __densities_;
5972        vector<result_type> __areas_;
5973    public:
5974        typedef piecewise_constant_distribution distribution_type;
5975
5976        param_type();
5977        template<class _InputIteratorB, class _InputIteratorW>
5978            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
5979                       _InputIteratorW __fW);
5980#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5981        template<class _UnaryOperation>
5982            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
5983#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5984        template<class _UnaryOperation>
5985            param_type(size_t __nw, result_type __xmin, result_type __xmax,
5986                       _UnaryOperation __fw);
5987        param_type & operator=(const param_type& __rhs);
5988
5989        _LIBCPP_INLINE_VISIBILITY
5990        vector<result_type> intervals() const {return __b_;}
5991        _LIBCPP_INLINE_VISIBILITY
5992        vector<result_type> densities() const {return __densities_;}
5993
5994        friend _LIBCPP_INLINE_VISIBILITY
5995            bool operator==(const param_type& __x, const param_type& __y)
5996            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
5997        friend _LIBCPP_INLINE_VISIBILITY
5998            bool operator!=(const param_type& __x, const param_type& __y)
5999            {return !(__x == __y);}
6000
6001    private:
6002        void __init();
6003
6004        friend class piecewise_constant_distribution;
6005
6006        template <class _CharT, class _Traits, class _RT>
6007        friend
6008        basic_ostream<_CharT, _Traits>&
6009        operator<<(basic_ostream<_CharT, _Traits>& __os,
6010                   const piecewise_constant_distribution<_RT>& __x);
6011
6012        template <class _CharT, class _Traits, class _RT>
6013        friend
6014        basic_istream<_CharT, _Traits>&
6015        operator>>(basic_istream<_CharT, _Traits>& __is,
6016                   piecewise_constant_distribution<_RT>& __x);
6017    };
6018
6019private:
6020    param_type __p_;
6021
6022public:
6023    // constructor and reset functions
6024    _LIBCPP_INLINE_VISIBILITY
6025    piecewise_constant_distribution() {}
6026    template<class _InputIteratorB, class _InputIteratorW>
6027        _LIBCPP_INLINE_VISIBILITY
6028        piecewise_constant_distribution(_InputIteratorB __fB,
6029                                        _InputIteratorB __lB,
6030                                        _InputIteratorW __fW)
6031        : __p_(__fB, __lB, __fW) {}
6032
6033#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6034    template<class _UnaryOperation>
6035        _LIBCPP_INLINE_VISIBILITY
6036        piecewise_constant_distribution(initializer_list<result_type> __bl,
6037                                        _UnaryOperation __fw)
6038        : __p_(__bl, __fw) {}
6039#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6040
6041    template<class _UnaryOperation>
6042        _LIBCPP_INLINE_VISIBILITY
6043        piecewise_constant_distribution(size_t __nw, result_type __xmin,
6044                                        result_type __xmax, _UnaryOperation __fw)
6045        : __p_(__nw, __xmin, __xmax, __fw) {}
6046
6047    _LIBCPP_INLINE_VISIBILITY
6048    explicit piecewise_constant_distribution(const param_type& __p)
6049        : __p_(__p) {}
6050
6051    _LIBCPP_INLINE_VISIBILITY
6052    void reset() {}
6053
6054    // generating functions
6055    template<class _URNG>
6056        _LIBCPP_INLINE_VISIBILITY
6057        result_type operator()(_URNG& __g)
6058        {return (*this)(__g, __p_);}
6059    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
6060
6061    // property functions
6062    _LIBCPP_INLINE_VISIBILITY
6063    vector<result_type> intervals() const {return __p_.intervals();}
6064    _LIBCPP_INLINE_VISIBILITY
6065    vector<result_type> densities() const {return __p_.densities();}
6066
6067    _LIBCPP_INLINE_VISIBILITY
6068    param_type param() const {return __p_;}
6069    _LIBCPP_INLINE_VISIBILITY
6070    void param(const param_type& __p) {__p_ = __p;}
6071
6072    _LIBCPP_INLINE_VISIBILITY
6073    result_type min() const {return __p_.__b_.front();}
6074    _LIBCPP_INLINE_VISIBILITY
6075    result_type max() const {return __p_.__b_.back();}
6076
6077    friend _LIBCPP_INLINE_VISIBILITY
6078        bool operator==(const piecewise_constant_distribution& __x,
6079                        const piecewise_constant_distribution& __y)
6080        {return __x.__p_ == __y.__p_;}
6081    friend _LIBCPP_INLINE_VISIBILITY
6082        bool operator!=(const piecewise_constant_distribution& __x,
6083                           const piecewise_constant_distribution& __y)
6084        {return !(__x == __y);}
6085
6086    template <class _CharT, class _Traits, class _RT>
6087    friend
6088    basic_ostream<_CharT, _Traits>&
6089    operator<<(basic_ostream<_CharT, _Traits>& __os,
6090               const piecewise_constant_distribution<_RT>& __x);
6091
6092    template <class _CharT, class _Traits, class _RT>
6093    friend
6094    basic_istream<_CharT, _Traits>&
6095    operator>>(basic_istream<_CharT, _Traits>& __is,
6096               piecewise_constant_distribution<_RT>& __x);
6097};
6098
6099template<class _RealType>
6100typename piecewise_constant_distribution<_RealType>::param_type &
6101piecewise_constant_distribution<_RealType>::param_type::operator=
6102                                                       (const param_type& __rhs)
6103{
6104//  These can throw
6105    __b_.reserve        (__rhs.__b_.size ());
6106    __densities_.reserve(__rhs.__densities_.size());
6107    __areas_.reserve    (__rhs.__areas_.size());
6108
6109//  These can not throw
6110    __b_         = __rhs.__b_;
6111    __densities_ = __rhs.__densities_;
6112    __areas_     =  __rhs.__areas_;
6113    return *this;
6114}
6115
6116template<class _RealType>
6117void
6118piecewise_constant_distribution<_RealType>::param_type::__init()
6119{
6120    // __densities_ contains non-normalized areas
6121    result_type __total_area = _VSTD::accumulate(__densities_.begin(),
6122                                                __densities_.end(),
6123                                                result_type());
6124    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6125        __densities_[__i] /= __total_area;
6126    // __densities_ contains normalized areas
6127    __areas_.assign(__densities_.size(), result_type());
6128    _VSTD::partial_sum(__densities_.begin(), __densities_.end() - 1,
6129                                                          __areas_.begin() + 1);
6130    // __areas_ contains partial sums of normalized areas: [0, __densities_ - 1]
6131    __densities_.back() = 1 - __areas_.back();  // correct round off error
6132    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6133        __densities_[__i] /= (__b_[__i+1] - __b_[__i]);
6134    // __densities_ now contains __densities_
6135}
6136
6137template<class _RealType>
6138piecewise_constant_distribution<_RealType>::param_type::param_type()
6139    : __b_(2),
6140      __densities_(1, 1.0),
6141      __areas_(1, 0.0)
6142{
6143    __b_[1] = 1;
6144}
6145
6146template<class _RealType>
6147template<class _InputIteratorB, class _InputIteratorW>
6148piecewise_constant_distribution<_RealType>::param_type::param_type(
6149        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
6150    : __b_(__fB, __lB)
6151{
6152    if (__b_.size() < 2)
6153    {
6154        __b_.resize(2);
6155        __b_[0] = 0;
6156        __b_[1] = 1;
6157        __densities_.assign(1, 1.0);
6158        __areas_.assign(1, 0.0);
6159    }
6160    else
6161    {
6162        __densities_.reserve(__b_.size() - 1);
6163        for (size_t __i = 0; __i < __b_.size() - 1; ++__i, ++__fW)
6164            __densities_.push_back(*__fW);
6165        __init();
6166    }
6167}
6168
6169#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6170
6171template<class _RealType>
6172template<class _UnaryOperation>
6173piecewise_constant_distribution<_RealType>::param_type::param_type(
6174        initializer_list<result_type> __bl, _UnaryOperation __fw)
6175    : __b_(__bl.begin(), __bl.end())
6176{
6177    if (__b_.size() < 2)
6178    {
6179        __b_.resize(2);
6180        __b_[0] = 0;
6181        __b_[1] = 1;
6182        __densities_.assign(1, 1.0);
6183        __areas_.assign(1, 0.0);
6184    }
6185    else
6186    {
6187        __densities_.reserve(__b_.size() - 1);
6188        for (size_t __i = 0; __i < __b_.size() - 1; ++__i)
6189            __densities_.push_back(__fw((__b_[__i+1] + __b_[__i])*.5));
6190        __init();
6191    }
6192}
6193
6194#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6195
6196template<class _RealType>
6197template<class _UnaryOperation>
6198piecewise_constant_distribution<_RealType>::param_type::param_type(
6199        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
6200    : __b_(__nw == 0 ? 2 : __nw + 1)
6201{
6202    size_t __n = __b_.size() - 1;
6203    result_type __d = (__xmax - __xmin) / __n;
6204    __densities_.reserve(__n);
6205    for (size_t __i = 0; __i < __n; ++__i)
6206    {
6207        __b_[__i] = __xmin + __i * __d;
6208        __densities_.push_back(__fw(__b_[__i] + __d*.5));
6209    }
6210    __b_[__n] = __xmax;
6211    __init();
6212}
6213
6214template<class _RealType>
6215template<class _URNG>
6216_RealType
6217piecewise_constant_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
6218{
6219    typedef uniform_real_distribution<result_type> _Gen;
6220    result_type __u = _Gen()(__g);
6221    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
6222                                      __u) - __p.__areas_.begin() - 1;
6223    return (__u - __p.__areas_[__k]) / __p.__densities_[__k] + __p.__b_[__k];
6224}
6225
6226template <class _CharT, class _Traits, class _RT>
6227basic_ostream<_CharT, _Traits>&
6228operator<<(basic_ostream<_CharT, _Traits>& __os,
6229           const piecewise_constant_distribution<_RT>& __x)
6230{
6231    __save_flags<_CharT, _Traits> _(__os);
6232    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6233               ios_base::scientific);
6234    _CharT __sp = __os.widen(' ');
6235    __os.fill(__sp);
6236    size_t __n = __x.__p_.__b_.size();
6237    __os << __n;
6238    for (size_t __i = 0; __i < __n; ++__i)
6239        __os << __sp << __x.__p_.__b_[__i];
6240    __n = __x.__p_.__densities_.size();
6241    __os << __sp << __n;
6242    for (size_t __i = 0; __i < __n; ++__i)
6243        __os << __sp << __x.__p_.__densities_[__i];
6244    __n = __x.__p_.__areas_.size();
6245    __os << __sp << __n;
6246    for (size_t __i = 0; __i < __n; ++__i)
6247        __os << __sp << __x.__p_.__areas_[__i];
6248    return __os;
6249}
6250
6251template <class _CharT, class _Traits, class _RT>
6252basic_istream<_CharT, _Traits>&
6253operator>>(basic_istream<_CharT, _Traits>& __is,
6254           piecewise_constant_distribution<_RT>& __x)
6255{
6256    typedef piecewise_constant_distribution<_RT> _Eng;
6257    typedef typename _Eng::result_type result_type;
6258    typedef typename _Eng::param_type param_type;
6259    __save_flags<_CharT, _Traits> _(__is);
6260    __is.flags(ios_base::dec | ios_base::skipws);
6261    size_t __n;
6262    __is >> __n;
6263    vector<result_type> __b(__n);
6264    for (size_t __i = 0; __i < __n; ++__i)
6265        __is >> __b[__i];
6266    __is >> __n;
6267    vector<result_type> __densities(__n);
6268    for (size_t __i = 0; __i < __n; ++__i)
6269        __is >> __densities[__i];
6270    __is >> __n;
6271    vector<result_type> __areas(__n);
6272    for (size_t __i = 0; __i < __n; ++__i)
6273        __is >> __areas[__i];
6274    if (!__is.fail())
6275    {
6276        swap(__x.__p_.__b_, __b);
6277        swap(__x.__p_.__densities_, __densities);
6278        swap(__x.__p_.__areas_, __areas);
6279    }
6280    return __is;
6281}
6282
6283// piecewise_linear_distribution
6284
6285template<class _RealType = double>
6286class _LIBCPP_VISIBLE piecewise_linear_distribution
6287{
6288public:
6289    // types
6290    typedef _RealType result_type;
6291
6292    class _LIBCPP_VISIBLE param_type
6293    {
6294        vector<result_type> __b_;
6295        vector<result_type> __densities_;
6296        vector<result_type> __areas_;
6297    public:
6298        typedef piecewise_linear_distribution distribution_type;
6299
6300        param_type();
6301        template<class _InputIteratorB, class _InputIteratorW>
6302            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
6303                       _InputIteratorW __fW);
6304#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6305        template<class _UnaryOperation>
6306            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
6307#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6308        template<class _UnaryOperation>
6309            param_type(size_t __nw, result_type __xmin, result_type __xmax,
6310                       _UnaryOperation __fw);
6311        param_type & operator=(const param_type& __rhs);
6312
6313        _LIBCPP_INLINE_VISIBILITY
6314        vector<result_type> intervals() const {return __b_;}
6315        _LIBCPP_INLINE_VISIBILITY
6316        vector<result_type> densities() const {return __densities_;}
6317
6318        friend _LIBCPP_INLINE_VISIBILITY
6319            bool operator==(const param_type& __x, const param_type& __y)
6320            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
6321        friend _LIBCPP_INLINE_VISIBILITY
6322            bool operator!=(const param_type& __x, const param_type& __y)
6323            {return !(__x == __y);}
6324
6325    private:
6326        void __init();
6327
6328        friend class piecewise_linear_distribution;
6329
6330        template <class _CharT, class _Traits, class _RT>
6331        friend
6332        basic_ostream<_CharT, _Traits>&
6333        operator<<(basic_ostream<_CharT, _Traits>& __os,
6334                   const piecewise_linear_distribution<_RT>& __x);
6335
6336        template <class _CharT, class _Traits, class _RT>
6337        friend
6338        basic_istream<_CharT, _Traits>&
6339        operator>>(basic_istream<_CharT, _Traits>& __is,
6340                   piecewise_linear_distribution<_RT>& __x);
6341    };
6342
6343private:
6344    param_type __p_;
6345
6346public:
6347    // constructor and reset functions
6348    _LIBCPP_INLINE_VISIBILITY
6349    piecewise_linear_distribution() {}
6350    template<class _InputIteratorB, class _InputIteratorW>
6351        _LIBCPP_INLINE_VISIBILITY
6352        piecewise_linear_distribution(_InputIteratorB __fB,
6353                                      _InputIteratorB __lB,
6354                                      _InputIteratorW __fW)
6355        : __p_(__fB, __lB, __fW) {}
6356
6357#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6358    template<class _UnaryOperation>
6359        _LIBCPP_INLINE_VISIBILITY
6360        piecewise_linear_distribution(initializer_list<result_type> __bl,
6361                                      _UnaryOperation __fw)
6362        : __p_(__bl, __fw) {}
6363#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6364
6365    template<class _UnaryOperation>
6366        _LIBCPP_INLINE_VISIBILITY
6367        piecewise_linear_distribution(size_t __nw, result_type __xmin,
6368                                      result_type __xmax, _UnaryOperation __fw)
6369        : __p_(__nw, __xmin, __xmax, __fw) {}
6370
6371    _LIBCPP_INLINE_VISIBILITY
6372    explicit piecewise_linear_distribution(const param_type& __p)
6373        : __p_(__p) {}
6374
6375    _LIBCPP_INLINE_VISIBILITY
6376    void reset() {}
6377
6378    // generating functions
6379    template<class _URNG>
6380        _LIBCPP_INLINE_VISIBILITY
6381        result_type operator()(_URNG& __g)
6382        {return (*this)(__g, __p_);}
6383    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
6384
6385    // property functions
6386    _LIBCPP_INLINE_VISIBILITY
6387    vector<result_type> intervals() const {return __p_.intervals();}
6388    _LIBCPP_INLINE_VISIBILITY
6389    vector<result_type> densities() const {return __p_.densities();}
6390
6391    _LIBCPP_INLINE_VISIBILITY
6392    param_type param() const {return __p_;}
6393    _LIBCPP_INLINE_VISIBILITY
6394    void param(const param_type& __p) {__p_ = __p;}
6395
6396    _LIBCPP_INLINE_VISIBILITY
6397    result_type min() const {return __p_.__b_.front();}
6398    _LIBCPP_INLINE_VISIBILITY
6399    result_type max() const {return __p_.__b_.back();}
6400
6401    friend _LIBCPP_INLINE_VISIBILITY
6402        bool operator==(const piecewise_linear_distribution& __x,
6403                        const piecewise_linear_distribution& __y)
6404        {return __x.__p_ == __y.__p_;}
6405    friend _LIBCPP_INLINE_VISIBILITY
6406        bool operator!=(const piecewise_linear_distribution& __x,
6407                        const piecewise_linear_distribution& __y)
6408        {return !(__x == __y);}
6409
6410    template <class _CharT, class _Traits, class _RT>
6411    friend
6412    basic_ostream<_CharT, _Traits>&
6413    operator<<(basic_ostream<_CharT, _Traits>& __os,
6414               const piecewise_linear_distribution<_RT>& __x);
6415
6416    template <class _CharT, class _Traits, class _RT>
6417    friend
6418    basic_istream<_CharT, _Traits>&
6419    operator>>(basic_istream<_CharT, _Traits>& __is,
6420               piecewise_linear_distribution<_RT>& __x);
6421};
6422
6423template<class _RealType>
6424typename piecewise_linear_distribution<_RealType>::param_type &
6425piecewise_linear_distribution<_RealType>::param_type::operator=
6426                                                       (const param_type& __rhs)
6427{
6428//  These can throw
6429    __b_.reserve        (__rhs.__b_.size ());
6430    __densities_.reserve(__rhs.__densities_.size());
6431    __areas_.reserve    (__rhs.__areas_.size());
6432
6433//  These can not throw
6434    __b_         = __rhs.__b_;
6435    __densities_ = __rhs.__densities_;
6436    __areas_     =  __rhs.__areas_;
6437    return *this;
6438}
6439
6440
6441template<class _RealType>
6442void
6443piecewise_linear_distribution<_RealType>::param_type::__init()
6444{
6445    __areas_.assign(__densities_.size() - 1, result_type());
6446    result_type _Sp = 0;
6447    for (size_t __i = 0; __i < __areas_.size(); ++__i)
6448    {
6449        __areas_[__i] = (__densities_[__i+1] + __densities_[__i]) *
6450                        (__b_[__i+1] - __b_[__i]) * .5;
6451        _Sp += __areas_[__i];
6452    }
6453    for (size_t __i = __areas_.size(); __i > 1;)
6454    {
6455        --__i;
6456        __areas_[__i] = __areas_[__i-1] / _Sp;
6457    }
6458    __areas_[0] = 0;
6459    for (size_t __i = 1; __i < __areas_.size(); ++__i)
6460        __areas_[__i] += __areas_[__i-1];
6461    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6462        __densities_[__i] /= _Sp;
6463}
6464
6465template<class _RealType>
6466piecewise_linear_distribution<_RealType>::param_type::param_type()
6467    : __b_(2),
6468      __densities_(2, 1.0),
6469      __areas_(1, 0.0)
6470{
6471    __b_[1] = 1;
6472}
6473
6474template<class _RealType>
6475template<class _InputIteratorB, class _InputIteratorW>
6476piecewise_linear_distribution<_RealType>::param_type::param_type(
6477        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
6478    : __b_(__fB, __lB)
6479{
6480    if (__b_.size() < 2)
6481    {
6482        __b_.resize(2);
6483        __b_[0] = 0;
6484        __b_[1] = 1;
6485        __densities_.assign(2, 1.0);
6486        __areas_.assign(1, 0.0);
6487    }
6488    else
6489    {
6490        __densities_.reserve(__b_.size());
6491        for (size_t __i = 0; __i < __b_.size(); ++__i, ++__fW)
6492            __densities_.push_back(*__fW);
6493        __init();
6494    }
6495}
6496
6497#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6498
6499template<class _RealType>
6500template<class _UnaryOperation>
6501piecewise_linear_distribution<_RealType>::param_type::param_type(
6502        initializer_list<result_type> __bl, _UnaryOperation __fw)
6503    : __b_(__bl.begin(), __bl.end())
6504{
6505    if (__b_.size() < 2)
6506    {
6507        __b_.resize(2);
6508        __b_[0] = 0;
6509        __b_[1] = 1;
6510        __densities_.assign(2, 1.0);
6511        __areas_.assign(1, 0.0);
6512    }
6513    else
6514    {
6515        __densities_.reserve(__b_.size());
6516        for (size_t __i = 0; __i < __b_.size(); ++__i)
6517            __densities_.push_back(__fw(__b_[__i]));
6518        __init();
6519    }
6520}
6521
6522#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6523
6524template<class _RealType>
6525template<class _UnaryOperation>
6526piecewise_linear_distribution<_RealType>::param_type::param_type(
6527        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
6528    : __b_(__nw == 0 ? 2 : __nw + 1)
6529{
6530    size_t __n = __b_.size() - 1;
6531    result_type __d = (__xmax - __xmin) / __n;
6532    __densities_.reserve(__b_.size());
6533    for (size_t __i = 0; __i < __n; ++__i)
6534    {
6535        __b_[__i] = __xmin + __i * __d;
6536        __densities_.push_back(__fw(__b_[__i]));
6537    }
6538    __b_[__n] = __xmax;
6539    __densities_.push_back(__fw(__b_[__n]));
6540    __init();
6541}
6542
6543template<class _RealType>
6544template<class _URNG>
6545_RealType
6546piecewise_linear_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
6547{
6548    typedef uniform_real_distribution<result_type> _Gen;
6549    result_type __u = _Gen()(__g);
6550    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
6551                                      __u) - __p.__areas_.begin() - 1;
6552    __u -= __p.__areas_[__k];
6553    const result_type __dk = __p.__densities_[__k];
6554    const result_type __dk1 = __p.__densities_[__k+1];
6555    const result_type __deltad = __dk1 - __dk;
6556    const result_type __bk = __p.__b_[__k];
6557    if (__deltad == 0)
6558        return __u / __dk + __bk;
6559    const result_type __bk1 = __p.__b_[__k+1];
6560    const result_type __deltab = __bk1 - __bk;
6561    return (__bk * __dk1 - __bk1 * __dk +
6562        _VSTD::sqrt(__deltab * (__deltab * __dk * __dk + 2 * __deltad * __u))) /
6563        __deltad;
6564}
6565
6566template <class _CharT, class _Traits, class _RT>
6567basic_ostream<_CharT, _Traits>&
6568operator<<(basic_ostream<_CharT, _Traits>& __os,
6569           const piecewise_linear_distribution<_RT>& __x)
6570{
6571    __save_flags<_CharT, _Traits> _(__os);
6572    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6573               ios_base::scientific);
6574    _CharT __sp = __os.widen(' ');
6575    __os.fill(__sp);
6576    size_t __n = __x.__p_.__b_.size();
6577    __os << __n;
6578    for (size_t __i = 0; __i < __n; ++__i)
6579        __os << __sp << __x.__p_.__b_[__i];
6580    __n = __x.__p_.__densities_.size();
6581    __os << __sp << __n;
6582    for (size_t __i = 0; __i < __n; ++__i)
6583        __os << __sp << __x.__p_.__densities_[__i];
6584    __n = __x.__p_.__areas_.size();
6585    __os << __sp << __n;
6586    for (size_t __i = 0; __i < __n; ++__i)
6587        __os << __sp << __x.__p_.__areas_[__i];
6588    return __os;
6589}
6590
6591template <class _CharT, class _Traits, class _RT>
6592basic_istream<_CharT, _Traits>&
6593operator>>(basic_istream<_CharT, _Traits>& __is,
6594           piecewise_linear_distribution<_RT>& __x)
6595{
6596    typedef piecewise_linear_distribution<_RT> _Eng;
6597    typedef typename _Eng::result_type result_type;
6598    typedef typename _Eng::param_type param_type;
6599    __save_flags<_CharT, _Traits> _(__is);
6600    __is.flags(ios_base::dec | ios_base::skipws);
6601    size_t __n;
6602    __is >> __n;
6603    vector<result_type> __b(__n);
6604    for (size_t __i = 0; __i < __n; ++__i)
6605        __is >> __b[__i];
6606    __is >> __n;
6607    vector<result_type> __densities(__n);
6608    for (size_t __i = 0; __i < __n; ++__i)
6609        __is >> __densities[__i];
6610    __is >> __n;
6611    vector<result_type> __areas(__n);
6612    for (size_t __i = 0; __i < __n; ++__i)
6613        __is >> __areas[__i];
6614    if (!__is.fail())
6615    {
6616        swap(__x.__p_.__b_, __b);
6617        swap(__x.__p_.__densities_, __densities);
6618        swap(__x.__p_.__areas_, __areas);
6619    }
6620    return __is;
6621}
6622
6623_LIBCPP_END_NAMESPACE_STD
6624
6625#endif  // _LIBCPP_RANDOM
6626