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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 noexcept;
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 noexcept;
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 noexcept;
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 noexcept;
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 <cstdint>
1638#include <cmath>
1639#include <type_traits>
1640#include <initializer_list>
1641#include <limits>
1642#include <algorithm>
1643#include <numeric>
1644#include <vector>
1645#include <string>
1646#include <istream>
1647#include <ostream>
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 _LIBCPP_TEMPLATE_VIS linear_congruential_engine;
1817
1818template <class _CharT, class _Traits,
1819          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1820_LIBCPP_INLINE_VISIBILITY
1821basic_ostream<_CharT, _Traits>&
1822operator<<(basic_ostream<_CharT, _Traits>& __os,
1823           const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
1824
1825template <class _CharT, class _Traits,
1826          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1827basic_istream<_CharT, _Traits>&
1828operator>>(basic_istream<_CharT, _Traits>& __is,
1829           linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
1830
1831template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1832class _LIBCPP_TEMPLATE_VIS linear_congruential_engine
1833{
1834public:
1835    // types
1836    typedef _UIntType result_type;
1837
1838private:
1839    result_type __x_;
1840
1841    static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0);
1842
1843    static_assert(__m == 0 || __a < __m, "linear_congruential_engine invalid parameters");
1844    static_assert(__m == 0 || __c < __m, "linear_congruential_engine invalid parameters");
1845public:
1846    static _LIBCPP_CONSTEXPR const result_type _Min = __c == 0u ? 1u: 0u;
1847    static _LIBCPP_CONSTEXPR const result_type _Max = __m - 1u;
1848    static_assert(_Min < _Max,           "linear_congruential_engine invalid parameters");
1849
1850    // engine characteristics
1851    static _LIBCPP_CONSTEXPR const result_type multiplier = __a;
1852    static _LIBCPP_CONSTEXPR const result_type increment = __c;
1853    static _LIBCPP_CONSTEXPR const result_type modulus = __m;
1854    _LIBCPP_INLINE_VISIBILITY
1855    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
1856    _LIBCPP_INLINE_VISIBILITY
1857    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
1858    static _LIBCPP_CONSTEXPR const result_type default_seed = 1u;
1859
1860    // constructors and seeding functions
1861    _LIBCPP_INLINE_VISIBILITY
1862    explicit linear_congruential_engine(result_type __s = default_seed)
1863        {seed(__s);}
1864    template<class _Sseq>
1865        _LIBCPP_INLINE_VISIBILITY
1866        explicit linear_congruential_engine(_Sseq& __q,
1867        typename enable_if<__is_seed_sequence<_Sseq, linear_congruential_engine>::value>::type* = 0)
1868        {seed(__q);}
1869    _LIBCPP_INLINE_VISIBILITY
1870    void seed(result_type __s = default_seed)
1871        {seed(integral_constant<bool, __m == 0>(),
1872              integral_constant<bool, __c == 0>(), __s);}
1873    template<class _Sseq>
1874        _LIBCPP_INLINE_VISIBILITY
1875        typename enable_if
1876        <
1877            __is_seed_sequence<_Sseq, linear_congruential_engine>::value,
1878            void
1879        >::type
1880        seed(_Sseq& __q)
1881            {__seed(__q, integral_constant<unsigned,
1882                1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32
1883                             :  (__m > 0x100000000ull))>());}
1884
1885    // generating functions
1886    _LIBCPP_INLINE_VISIBILITY
1887    result_type operator()()
1888        {return __x_ = static_cast<result_type>(__lce_ta<__a, __c, __m, _Mp>::next(__x_));}
1889    _LIBCPP_INLINE_VISIBILITY
1890    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
1891
1892    friend _LIBCPP_INLINE_VISIBILITY
1893    bool operator==(const linear_congruential_engine& __x,
1894                    const linear_congruential_engine& __y)
1895        {return __x.__x_ == __y.__x_;}
1896    friend _LIBCPP_INLINE_VISIBILITY
1897    bool operator!=(const linear_congruential_engine& __x,
1898                    const linear_congruential_engine& __y)
1899        {return !(__x == __y);}
1900
1901private:
1902
1903    _LIBCPP_INLINE_VISIBILITY
1904    void seed(true_type, true_type, result_type __s) {__x_ = __s == 0 ? 1 : __s;}
1905    _LIBCPP_INLINE_VISIBILITY
1906    void seed(true_type, false_type, result_type __s) {__x_ = __s;}
1907    _LIBCPP_INLINE_VISIBILITY
1908    void seed(false_type, true_type, result_type __s) {__x_ = __s % __m == 0 ?
1909                                                                 1 : __s % __m;}
1910    _LIBCPP_INLINE_VISIBILITY
1911    void seed(false_type, false_type, result_type __s) {__x_ = __s % __m;}
1912
1913    template<class _Sseq>
1914        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
1915    template<class _Sseq>
1916        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
1917
1918    template <class _CharT, class _Traits,
1919              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1920    friend
1921    basic_ostream<_CharT, _Traits>&
1922    operator<<(basic_ostream<_CharT, _Traits>& __os,
1923               const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
1924
1925    template <class _CharT, class _Traits,
1926              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1927    friend
1928    basic_istream<_CharT, _Traits>&
1929    operator>>(basic_istream<_CharT, _Traits>& __is,
1930               linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
1931};
1932
1933template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1934    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1935    linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
1936
1937template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1938    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1939    linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
1940
1941template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1942    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1943    linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
1944
1945template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1946    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1947    linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
1948
1949template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1950template<class _Sseq>
1951void
1952linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
1953                                                 integral_constant<unsigned, 1>)
1954{
1955    const unsigned __k = 1;
1956    uint32_t __ar[__k+3];
1957    __q.generate(__ar, __ar + __k + 3);
1958    result_type __s = static_cast<result_type>(__ar[3] % __m);
1959    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
1960}
1961
1962template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1963template<class _Sseq>
1964void
1965linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
1966                                                 integral_constant<unsigned, 2>)
1967{
1968    const unsigned __k = 2;
1969    uint32_t __ar[__k+3];
1970    __q.generate(__ar, __ar + __k + 3);
1971    result_type __s = static_cast<result_type>((__ar[3] +
1972                                              ((uint64_t)__ar[4] << 32)) % __m);
1973    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
1974}
1975
1976template <class _CharT, class _Traits,
1977          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1978inline _LIBCPP_INLINE_VISIBILITY
1979basic_ostream<_CharT, _Traits>&
1980operator<<(basic_ostream<_CharT, _Traits>& __os,
1981           const linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
1982{
1983    __save_flags<_CharT, _Traits> __lx(__os);
1984    __os.flags(ios_base::dec | ios_base::left);
1985    __os.fill(__os.widen(' '));
1986    return __os << __x.__x_;
1987}
1988
1989template <class _CharT, class _Traits,
1990          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1991basic_istream<_CharT, _Traits>&
1992operator>>(basic_istream<_CharT, _Traits>& __is,
1993           linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
1994{
1995    __save_flags<_CharT, _Traits> __lx(__is);
1996    __is.flags(ios_base::dec | ios_base::skipws);
1997    _UIntType __t;
1998    __is >> __t;
1999    if (!__is.fail())
2000        __x.__x_ = __t;
2001    return __is;
2002}
2003
2004typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
2005                                                                   minstd_rand0;
2006typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
2007                                                                    minstd_rand;
2008typedef minstd_rand                                       default_random_engine;
2009// mersenne_twister_engine
2010
2011template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2012          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2013          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2014class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine;
2015
2016template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2017          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2018          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2019bool
2020operator==(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2021                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2022           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2023                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2024
2025template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2026          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2027          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2028_LIBCPP_INLINE_VISIBILITY
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 _CharT, class _Traits,
2036          class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2037          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2038          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2039basic_ostream<_CharT, _Traits>&
2040operator<<(basic_ostream<_CharT, _Traits>& __os,
2041           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2042                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
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_istream<_CharT, _Traits>&
2049operator>>(basic_istream<_CharT, _Traits>& __is,
2050           mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2051                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2052
2053template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2054          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2055          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2056class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine
2057{
2058public:
2059    // types
2060    typedef _UIntType result_type;
2061
2062private:
2063    result_type __x_[__n];
2064    size_t      __i_;
2065
2066    static_assert(  0 <  __m, "mersenne_twister_engine invalid parameters");
2067    static_assert(__m <= __n, "mersenne_twister_engine invalid parameters");
2068    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
2069    static_assert(__w <= _Dt, "mersenne_twister_engine invalid parameters");
2070    static_assert(  2 <= __w, "mersenne_twister_engine invalid parameters");
2071    static_assert(__r <= __w, "mersenne_twister_engine invalid parameters");
2072    static_assert(__u <= __w, "mersenne_twister_engine invalid parameters");
2073    static_assert(__s <= __w, "mersenne_twister_engine invalid parameters");
2074    static_assert(__t <= __w, "mersenne_twister_engine invalid parameters");
2075    static_assert(__l <= __w, "mersenne_twister_engine invalid parameters");
2076public:
2077    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
2078    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
2079                                                      (result_type(1) << __w) - result_type(1);
2080    static_assert(_Min < _Max, "mersenne_twister_engine invalid parameters");
2081    static_assert(__a <= _Max, "mersenne_twister_engine invalid parameters");
2082    static_assert(__b <= _Max, "mersenne_twister_engine invalid parameters");
2083    static_assert(__c <= _Max, "mersenne_twister_engine invalid parameters");
2084    static_assert(__d <= _Max, "mersenne_twister_engine invalid parameters");
2085    static_assert(__f <= _Max, "mersenne_twister_engine invalid parameters");
2086
2087    // engine characteristics
2088    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
2089    static _LIBCPP_CONSTEXPR const size_t state_size = __n;
2090    static _LIBCPP_CONSTEXPR const size_t shift_size = __m;
2091    static _LIBCPP_CONSTEXPR const size_t mask_bits = __r;
2092    static _LIBCPP_CONSTEXPR const result_type xor_mask = __a;
2093    static _LIBCPP_CONSTEXPR const size_t tempering_u = __u;
2094    static _LIBCPP_CONSTEXPR const result_type tempering_d = __d;
2095    static _LIBCPP_CONSTEXPR const size_t tempering_s = __s;
2096    static _LIBCPP_CONSTEXPR const result_type tempering_b = __b;
2097    static _LIBCPP_CONSTEXPR const size_t tempering_t = __t;
2098    static _LIBCPP_CONSTEXPR const result_type tempering_c = __c;
2099    static _LIBCPP_CONSTEXPR const size_t tempering_l = __l;
2100    static _LIBCPP_CONSTEXPR const result_type initialization_multiplier = __f;
2101    _LIBCPP_INLINE_VISIBILITY
2102    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
2103    _LIBCPP_INLINE_VISIBILITY
2104    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
2105    static _LIBCPP_CONSTEXPR const result_type default_seed = 5489u;
2106
2107    // constructors and seeding functions
2108    _LIBCPP_INLINE_VISIBILITY
2109    explicit mersenne_twister_engine(result_type __sd = default_seed)
2110        {seed(__sd);}
2111    template<class _Sseq>
2112        _LIBCPP_INLINE_VISIBILITY
2113        explicit mersenne_twister_engine(_Sseq& __q,
2114        typename enable_if<__is_seed_sequence<_Sseq, mersenne_twister_engine>::value>::type* = 0)
2115        {seed(__q);}
2116    void seed(result_type __sd = default_seed);
2117    template<class _Sseq>
2118        _LIBCPP_INLINE_VISIBILITY
2119        typename enable_if
2120        <
2121            __is_seed_sequence<_Sseq, mersenne_twister_engine>::value,
2122            void
2123        >::type
2124        seed(_Sseq& __q)
2125            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2126
2127    // generating functions
2128    result_type operator()();
2129    _LIBCPP_INLINE_VISIBILITY
2130    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2131
2132    template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2133              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2134              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2135    friend
2136    bool
2137    operator==(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2138                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2139               const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2140                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2141
2142    template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2143              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2144              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2145    friend
2146    bool
2147    operator!=(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2148                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2149               const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2150                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2151
2152    template <class _CharT, class _Traits,
2153              class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2154              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2155              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2156    friend
2157    basic_ostream<_CharT, _Traits>&
2158    operator<<(basic_ostream<_CharT, _Traits>& __os,
2159               const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2160                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2161
2162    template <class _CharT, class _Traits,
2163              class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2164              _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2165              _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2166    friend
2167    basic_istream<_CharT, _Traits>&
2168    operator>>(basic_istream<_CharT, _Traits>& __is,
2169               mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2170                                       _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2171private:
2172
2173    template<class _Sseq>
2174        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
2175    template<class _Sseq>
2176        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
2177
2178    template <size_t __count>
2179        _LIBCPP_INLINE_VISIBILITY
2180        static
2181        typename enable_if
2182        <
2183            __count < __w,
2184            result_type
2185        >::type
2186        __lshift(result_type __x) {return (__x << __count) & _Max;}
2187
2188    template <size_t __count>
2189        _LIBCPP_INLINE_VISIBILITY
2190        static
2191        typename enable_if
2192        <
2193            (__count >= __w),
2194            result_type
2195        >::type
2196        __lshift(result_type) {return result_type(0);}
2197
2198    template <size_t __count>
2199        _LIBCPP_INLINE_VISIBILITY
2200        static
2201        typename enable_if
2202        <
2203            __count < _Dt,
2204            result_type
2205        >::type
2206        __rshift(result_type __x) {return __x >> __count;}
2207
2208    template <size_t __count>
2209        _LIBCPP_INLINE_VISIBILITY
2210        static
2211        typename enable_if
2212        <
2213            (__count >= _Dt),
2214            result_type
2215        >::type
2216        __rshift(result_type) {return result_type(0);}
2217};
2218
2219template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2220          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2221          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2222    _LIBCPP_CONSTEXPR const size_t
2223    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::word_size;
2224
2225template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2226          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2227          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2228    _LIBCPP_CONSTEXPR const size_t
2229    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::state_size;
2230
2231template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2232          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2233          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2234    _LIBCPP_CONSTEXPR const size_t
2235    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::shift_size;
2236
2237template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2238          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2239          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2240    _LIBCPP_CONSTEXPR const size_t
2241    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::mask_bits;
2242
2243template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2244          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2245          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2246    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2247    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::xor_mask;
2248
2249template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2250          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2251          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2252    _LIBCPP_CONSTEXPR const size_t
2253    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_u;
2254
2255template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2256          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2257          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2258    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2259    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_d;
2260
2261template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2262          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2263          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2264    _LIBCPP_CONSTEXPR const size_t
2265    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_s;
2266
2267template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2268          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2269          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2270    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2271    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_b;
2272
2273template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2274          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2275          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2276    _LIBCPP_CONSTEXPR const size_t
2277    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_t;
2278
2279template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2280          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2281          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2282    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2283    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_c;
2284
2285template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2286          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2287          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2288    _LIBCPP_CONSTEXPR const size_t
2289    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_l;
2290
2291template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2292          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2293          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2294    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2295    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::initialization_multiplier;
2296
2297template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2298          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2299          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2300    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2301    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::default_seed;
2302
2303template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2304          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2305          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2306void
2307mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2308    __t, __c, __l, __f>::seed(result_type __sd)
2309{   // __w >= 2
2310    __x_[0] = __sd & _Max;
2311    for (size_t __i = 1; __i < __n; ++__i)
2312        __x_[__i] = (__f * (__x_[__i-1] ^ __rshift<__w - 2>(__x_[__i-1])) + __i) & _Max;
2313    __i_ = 0;
2314}
2315
2316template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2317          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2318          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2319template<class _Sseq>
2320void
2321mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2322    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 1>)
2323{
2324    const unsigned __k = 1;
2325    uint32_t __ar[__n * __k];
2326    __q.generate(__ar, __ar + __n * __k);
2327    for (size_t __i = 0; __i < __n; ++__i)
2328        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
2329    const result_type __mask = __r == _Dt ? result_type(~0) :
2330                                       (result_type(1) << __r) - result_type(1);
2331    __i_ = 0;
2332    if ((__x_[0] & ~__mask) == 0)
2333    {
2334        for (size_t __i = 1; __i < __n; ++__i)
2335            if (__x_[__i] != 0)
2336                return;
2337        __x_[0] = _Max;
2338    }
2339}
2340
2341template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2342          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2343          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2344template<class _Sseq>
2345void
2346mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2347    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 2>)
2348{
2349    const unsigned __k = 2;
2350    uint32_t __ar[__n * __k];
2351    __q.generate(__ar, __ar + __n * __k);
2352    for (size_t __i = 0; __i < __n; ++__i)
2353        __x_[__i] = static_cast<result_type>(
2354            (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
2355    const result_type __mask = __r == _Dt ? result_type(~0) :
2356                                       (result_type(1) << __r) - result_type(1);
2357    __i_ = 0;
2358    if ((__x_[0] & ~__mask) == 0)
2359    {
2360        for (size_t __i = 1; __i < __n; ++__i)
2361            if (__x_[__i] != 0)
2362                return;
2363        __x_[0] = _Max;
2364    }
2365}
2366
2367template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2368          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2369          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2370_UIntType
2371mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2372    __t, __c, __l, __f>::operator()()
2373{
2374    const size_t __j = (__i_ + 1) % __n;
2375    const result_type __mask = __r == _Dt ? result_type(~0) :
2376                                       (result_type(1) << __r) - result_type(1);
2377    const result_type _Yp = (__x_[__i_] & ~__mask) | (__x_[__j] & __mask);
2378    const size_t __k = (__i_ + __m) % __n;
2379    __x_[__i_] = __x_[__k] ^ __rshift<1>(_Yp) ^ (__a * (_Yp & 1));
2380    result_type __z = __x_[__i_] ^ (__rshift<__u>(__x_[__i_]) & __d);
2381    __i_ = __j;
2382    __z ^= __lshift<__s>(__z) & __b;
2383    __z ^= __lshift<__t>(__z) & __c;
2384    return __z ^ __rshift<__l>(__z);
2385}
2386
2387template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2388          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2389          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2390bool
2391operator==(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2392                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2393           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2394                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
2395{
2396    if (__x.__i_ == __y.__i_)
2397        return _VSTD::equal(__x.__x_, __x.__x_ + _Np, __y.__x_);
2398    if (__x.__i_ == 0 || __y.__i_ == 0)
2399    {
2400        size_t __j = _VSTD::min(_Np - __x.__i_, _Np - __y.__i_);
2401        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
2402                         __y.__x_ + __y.__i_))
2403            return false;
2404        if (__x.__i_ == 0)
2405            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Np, __y.__x_);
2406        return _VSTD::equal(__x.__x_, __x.__x_ + (_Np - __j), __y.__x_ + __j);
2407    }
2408    if (__x.__i_ < __y.__i_)
2409    {
2410        size_t __j = _Np - __y.__i_;
2411        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
2412                         __y.__x_ + __y.__i_))
2413            return false;
2414        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Np,
2415                         __y.__x_))
2416            return false;
2417        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
2418                           __y.__x_ + (_Np - (__x.__i_ + __j)));
2419    }
2420    size_t __j = _Np - __x.__i_;
2421    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
2422                     __x.__x_ + __x.__i_))
2423        return false;
2424    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Np,
2425                     __x.__x_))
2426        return false;
2427    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
2428                       __x.__x_ + (_Np - (__y.__i_ + __j)));
2429}
2430
2431template <class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2432          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2433          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2434inline _LIBCPP_INLINE_VISIBILITY
2435bool
2436operator!=(const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2437                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2438           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2439                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
2440{
2441    return !(__x == __y);
2442}
2443
2444template <class _CharT, class _Traits,
2445          class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2446          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2447          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2448basic_ostream<_CharT, _Traits>&
2449operator<<(basic_ostream<_CharT, _Traits>& __os,
2450           const mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2451                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
2452{
2453    __save_flags<_CharT, _Traits> __lx(__os);
2454    __os.flags(ios_base::dec | ios_base::left);
2455    _CharT __sp = __os.widen(' ');
2456    __os.fill(__sp);
2457    __os << __x.__x_[__x.__i_];
2458    for (size_t __j = __x.__i_ + 1; __j < _Np; ++__j)
2459        __os << __sp << __x.__x_[__j];
2460    for (size_t __j = 0; __j < __x.__i_; ++__j)
2461        __os << __sp << __x.__x_[__j];
2462    return __os;
2463}
2464
2465template <class _CharT, class _Traits,
2466          class _UI, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2467          _UI _Ap, size_t _Up, _UI _Dp, size_t _Sp,
2468          _UI _Bp, size_t _Tp, _UI _Cp, size_t _Lp, _UI _Fp>
2469basic_istream<_CharT, _Traits>&
2470operator>>(basic_istream<_CharT, _Traits>& __is,
2471           mersenne_twister_engine<_UI, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2472                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
2473{
2474    __save_flags<_CharT, _Traits> __lx(__is);
2475    __is.flags(ios_base::dec | ios_base::skipws);
2476    _UI __t[_Np];
2477    for (size_t __i = 0; __i < _Np; ++__i)
2478        __is >> __t[__i];
2479    if (!__is.fail())
2480    {
2481        for (size_t __i = 0; __i < _Np; ++__i)
2482            __x.__x_[__i] = __t[__i];
2483        __x.__i_ = 0;
2484    }
2485    return __is;
2486}
2487
2488typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
2489                                0x9908b0df, 11, 0xffffffff,
2490                                7,  0x9d2c5680,
2491                                15, 0xefc60000,
2492                                18, 1812433253>                         mt19937;
2493typedef mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
2494                                0xb5026f5aa96619e9ULL, 29, 0x5555555555555555ULL,
2495                                17, 0x71d67fffeda60000ULL,
2496                                37, 0xfff7eee000000000ULL,
2497                                43, 6364136223846793005ULL>          mt19937_64;
2498
2499// subtract_with_carry_engine
2500
2501template<class _UIntType, size_t __w, size_t __s, size_t __r>
2502class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine;
2503
2504template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2505bool
2506operator==(
2507    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2508    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2509
2510template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2511_LIBCPP_INLINE_VISIBILITY
2512bool
2513operator!=(
2514    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2515    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2516
2517template <class _CharT, class _Traits,
2518          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2519basic_ostream<_CharT, _Traits>&
2520operator<<(basic_ostream<_CharT, _Traits>& __os,
2521           const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2522
2523template <class _CharT, class _Traits,
2524          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2525basic_istream<_CharT, _Traits>&
2526operator>>(basic_istream<_CharT, _Traits>& __is,
2527           subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2528
2529template<class _UIntType, size_t __w, size_t __s, size_t __r>
2530class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine
2531{
2532public:
2533    // types
2534    typedef _UIntType result_type;
2535
2536private:
2537    result_type __x_[__r];
2538    result_type  __c_;
2539    size_t      __i_;
2540
2541    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
2542    static_assert(  0 <  __w, "subtract_with_carry_engine invalid parameters");
2543    static_assert(__w <= _Dt, "subtract_with_carry_engine invalid parameters");
2544    static_assert(  0 <  __s, "subtract_with_carry_engine invalid parameters");
2545    static_assert(__s <  __r, "subtract_with_carry_engine invalid parameters");
2546public:
2547    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
2548    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
2549                                                      (result_type(1) << __w) - result_type(1);
2550    static_assert(_Min < _Max, "subtract_with_carry_engine invalid parameters");
2551
2552    // engine characteristics
2553    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
2554    static _LIBCPP_CONSTEXPR const size_t short_lag = __s;
2555    static _LIBCPP_CONSTEXPR const size_t long_lag = __r;
2556    _LIBCPP_INLINE_VISIBILITY
2557    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
2558    _LIBCPP_INLINE_VISIBILITY
2559    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
2560    static _LIBCPP_CONSTEXPR const result_type default_seed = 19780503u;
2561
2562    // constructors and seeding functions
2563    _LIBCPP_INLINE_VISIBILITY
2564    explicit subtract_with_carry_engine(result_type __sd = default_seed)
2565        {seed(__sd);}
2566    template<class _Sseq>
2567        _LIBCPP_INLINE_VISIBILITY
2568        explicit subtract_with_carry_engine(_Sseq& __q,
2569        typename enable_if<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value>::type* = 0)
2570        {seed(__q);}
2571    _LIBCPP_INLINE_VISIBILITY
2572    void seed(result_type __sd = default_seed)
2573        {seed(__sd, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2574    template<class _Sseq>
2575        _LIBCPP_INLINE_VISIBILITY
2576        typename enable_if
2577        <
2578            __is_seed_sequence<_Sseq, subtract_with_carry_engine>::value,
2579            void
2580        >::type
2581        seed(_Sseq& __q)
2582            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2583
2584    // generating functions
2585    result_type operator()();
2586    _LIBCPP_INLINE_VISIBILITY
2587    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2588
2589    template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2590    friend
2591    bool
2592    operator==(
2593        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2594        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2595
2596    template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2597    friend
2598    bool
2599    operator!=(
2600        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2601        const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y);
2602
2603    template <class _CharT, class _Traits,
2604              class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2605    friend
2606    basic_ostream<_CharT, _Traits>&
2607    operator<<(basic_ostream<_CharT, _Traits>& __os,
2608               const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2609
2610    template <class _CharT, class _Traits,
2611              class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2612    friend
2613    basic_istream<_CharT, _Traits>&
2614    operator>>(basic_istream<_CharT, _Traits>& __is,
2615               subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x);
2616
2617private:
2618
2619    void seed(result_type __sd, integral_constant<unsigned, 1>);
2620    void seed(result_type __sd, integral_constant<unsigned, 2>);
2621    template<class _Sseq>
2622        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
2623    template<class _Sseq>
2624        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
2625};
2626
2627template<class _UIntType, size_t __w, size_t __s, size_t __r>
2628    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::word_size;
2629
2630template<class _UIntType, size_t __w, size_t __s, size_t __r>
2631    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::short_lag;
2632
2633template<class _UIntType, size_t __w, size_t __s, size_t __r>
2634    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::long_lag;
2635
2636template<class _UIntType, size_t __w, size_t __s, size_t __r>
2637    _LIBCPP_CONSTEXPR const typename subtract_with_carry_engine<_UIntType, __w, __s, __r>::result_type
2638    subtract_with_carry_engine<_UIntType, __w, __s, __r>::default_seed;
2639
2640template<class _UIntType, size_t __w, size_t __s, size_t __r>
2641void
2642subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
2643        integral_constant<unsigned, 1>)
2644{
2645    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
2646        __e(__sd == 0u ? default_seed : __sd);
2647    for (size_t __i = 0; __i < __r; ++__i)
2648        __x_[__i] = static_cast<result_type>(__e() & _Max);
2649    __c_ = __x_[__r-1] == 0;
2650    __i_ = 0;
2651}
2652
2653template<class _UIntType, size_t __w, size_t __s, size_t __r>
2654void
2655subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
2656        integral_constant<unsigned, 2>)
2657{
2658    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
2659        __e(__sd == 0u ? default_seed : __sd);
2660    for (size_t __i = 0; __i < __r; ++__i)
2661    {
2662        result_type __e0 = __e();
2663        __x_[__i] = static_cast<result_type>(
2664                                    (__e0 + ((uint64_t)__e() << 32)) & _Max);
2665    }
2666    __c_ = __x_[__r-1] == 0;
2667    __i_ = 0;
2668}
2669
2670template<class _UIntType, size_t __w, size_t __s, size_t __r>
2671template<class _Sseq>
2672void
2673subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
2674        integral_constant<unsigned, 1>)
2675{
2676    const unsigned __k = 1;
2677    uint32_t __ar[__r * __k];
2678    __q.generate(__ar, __ar + __r * __k);
2679    for (size_t __i = 0; __i < __r; ++__i)
2680        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
2681    __c_ = __x_[__r-1] == 0;
2682    __i_ = 0;
2683}
2684
2685template<class _UIntType, size_t __w, size_t __s, size_t __r>
2686template<class _Sseq>
2687void
2688subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
2689        integral_constant<unsigned, 2>)
2690{
2691    const unsigned __k = 2;
2692    uint32_t __ar[__r * __k];
2693    __q.generate(__ar, __ar + __r * __k);
2694    for (size_t __i = 0; __i < __r; ++__i)
2695        __x_[__i] = static_cast<result_type>(
2696                  (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
2697    __c_ = __x_[__r-1] == 0;
2698    __i_ = 0;
2699}
2700
2701template<class _UIntType, size_t __w, size_t __s, size_t __r>
2702_UIntType
2703subtract_with_carry_engine<_UIntType, __w, __s, __r>::operator()()
2704{
2705    const result_type& __xs = __x_[(__i_ + (__r - __s)) % __r];
2706    result_type& __xr = __x_[__i_];
2707    result_type __new_c = __c_ == 0 ? __xs < __xr : __xs != 0 ? __xs <= __xr : 1;
2708    __xr = (__xs - __xr - __c_) & _Max;
2709    __c_ = __new_c;
2710    __i_ = (__i_ + 1) % __r;
2711    return __xr;
2712}
2713
2714template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2715bool
2716operator==(
2717    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2718    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y)
2719{
2720    if (__x.__c_ != __y.__c_)
2721        return false;
2722    if (__x.__i_ == __y.__i_)
2723        return _VSTD::equal(__x.__x_, __x.__x_ + _Rp, __y.__x_);
2724    if (__x.__i_ == 0 || __y.__i_ == 0)
2725    {
2726        size_t __j = _VSTD::min(_Rp - __x.__i_, _Rp - __y.__i_);
2727        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
2728                         __y.__x_ + __y.__i_))
2729            return false;
2730        if (__x.__i_ == 0)
2731            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Rp, __y.__x_);
2732        return _VSTD::equal(__x.__x_, __x.__x_ + (_Rp - __j), __y.__x_ + __j);
2733    }
2734    if (__x.__i_ < __y.__i_)
2735    {
2736        size_t __j = _Rp - __y.__i_;
2737        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
2738                         __y.__x_ + __y.__i_))
2739            return false;
2740        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Rp,
2741                         __y.__x_))
2742            return false;
2743        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
2744                           __y.__x_ + (_Rp - (__x.__i_ + __j)));
2745    }
2746    size_t __j = _Rp - __x.__i_;
2747    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
2748                     __x.__x_ + __x.__i_))
2749        return false;
2750    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Rp,
2751                     __x.__x_))
2752        return false;
2753    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
2754                       __x.__x_ + (_Rp - (__y.__i_ + __j)));
2755}
2756
2757template<class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2758inline _LIBCPP_INLINE_VISIBILITY
2759bool
2760operator!=(
2761    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x,
2762    const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __y)
2763{
2764    return !(__x == __y);
2765}
2766
2767template <class _CharT, class _Traits,
2768          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2769basic_ostream<_CharT, _Traits>&
2770operator<<(basic_ostream<_CharT, _Traits>& __os,
2771           const subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x)
2772{
2773    __save_flags<_CharT, _Traits> __lx(__os);
2774    __os.flags(ios_base::dec | ios_base::left);
2775    _CharT __sp = __os.widen(' ');
2776    __os.fill(__sp);
2777    __os << __x.__x_[__x.__i_];
2778    for (size_t __j = __x.__i_ + 1; __j < _Rp; ++__j)
2779        __os << __sp << __x.__x_[__j];
2780    for (size_t __j = 0; __j < __x.__i_; ++__j)
2781        __os << __sp << __x.__x_[__j];
2782    __os << __sp << __x.__c_;
2783    return __os;
2784}
2785
2786template <class _CharT, class _Traits,
2787          class _UI, size_t _Wp, size_t _Sp, size_t _Rp>
2788basic_istream<_CharT, _Traits>&
2789operator>>(basic_istream<_CharT, _Traits>& __is,
2790           subtract_with_carry_engine<_UI, _Wp, _Sp, _Rp>& __x)
2791{
2792    __save_flags<_CharT, _Traits> __lx(__is);
2793    __is.flags(ios_base::dec | ios_base::skipws);
2794    _UI __t[_Rp+1];
2795    for (size_t __i = 0; __i < _Rp+1; ++__i)
2796        __is >> __t[__i];
2797    if (!__is.fail())
2798    {
2799        for (size_t __i = 0; __i < _Rp; ++__i)
2800            __x.__x_[__i] = __t[__i];
2801        __x.__c_ = __t[_Rp];
2802        __x.__i_ = 0;
2803    }
2804    return __is;
2805}
2806
2807typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>     ranlux24_base;
2808typedef subtract_with_carry_engine<uint_fast64_t, 48,  5, 12>     ranlux48_base;
2809
2810// discard_block_engine
2811
2812template<class _Engine, size_t __p, size_t __r>
2813class _LIBCPP_TEMPLATE_VIS discard_block_engine
2814{
2815    _Engine __e_;
2816    int     __n_;
2817
2818    static_assert(  0 <  __r, "discard_block_engine invalid parameters");
2819    static_assert(__r <= __p, "discard_block_engine invalid parameters");
2820    static_assert(__r <= INT_MAX, "discard_block_engine invalid parameters");
2821public:
2822    // types
2823    typedef typename _Engine::result_type result_type;
2824
2825    // engine characteristics
2826    static _LIBCPP_CONSTEXPR const size_t block_size = __p;
2827    static _LIBCPP_CONSTEXPR const size_t used_block = __r;
2828
2829#ifdef _LIBCPP_HAS_NO_CONSTEXPR
2830    static const result_type _Min = _Engine::_Min;
2831    static const result_type _Max = _Engine::_Max;
2832#else
2833    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
2834    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
2835#endif
2836
2837    _LIBCPP_INLINE_VISIBILITY
2838    static _LIBCPP_CONSTEXPR result_type min() { return _Engine::min(); }
2839    _LIBCPP_INLINE_VISIBILITY
2840    static _LIBCPP_CONSTEXPR result_type max() { return _Engine::max(); }
2841
2842    // constructors and seeding functions
2843    _LIBCPP_INLINE_VISIBILITY
2844    discard_block_engine() : __n_(0) {}
2845    _LIBCPP_INLINE_VISIBILITY
2846    explicit discard_block_engine(const _Engine& __e)
2847        : __e_(__e), __n_(0) {}
2848#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2849    _LIBCPP_INLINE_VISIBILITY
2850    explicit discard_block_engine(_Engine&& __e)
2851        : __e_(_VSTD::move(__e)), __n_(0) {}
2852#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2853    _LIBCPP_INLINE_VISIBILITY
2854    explicit discard_block_engine(result_type __sd) : __e_(__sd), __n_(0) {}
2855    template<class _Sseq>
2856        _LIBCPP_INLINE_VISIBILITY
2857        explicit discard_block_engine(_Sseq& __q,
2858        typename enable_if<__is_seed_sequence<_Sseq, discard_block_engine>::value &&
2859                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
2860        : __e_(__q), __n_(0) {}
2861    _LIBCPP_INLINE_VISIBILITY
2862    void seed() {__e_.seed(); __n_ = 0;}
2863    _LIBCPP_INLINE_VISIBILITY
2864    void seed(result_type __sd) {__e_.seed(__sd); __n_ = 0;}
2865    template<class _Sseq>
2866        _LIBCPP_INLINE_VISIBILITY
2867        typename enable_if
2868        <
2869            __is_seed_sequence<_Sseq, discard_block_engine>::value,
2870            void
2871        >::type
2872        seed(_Sseq& __q) {__e_.seed(__q); __n_ = 0;}
2873
2874    // generating functions
2875    result_type operator()();
2876    _LIBCPP_INLINE_VISIBILITY
2877    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2878
2879    // property functions
2880    _LIBCPP_INLINE_VISIBILITY
2881    const _Engine& base() const _NOEXCEPT {return __e_;}
2882
2883    template<class _Eng, size_t _Pp, size_t _Rp>
2884    friend
2885    bool
2886    operator==(
2887        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2888        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
2889
2890    template<class _Eng, size_t _Pp, size_t _Rp>
2891    friend
2892    bool
2893    operator!=(
2894        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2895        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
2896
2897    template <class _CharT, class _Traits,
2898              class _Eng, size_t _Pp, size_t _Rp>
2899    friend
2900    basic_ostream<_CharT, _Traits>&
2901    operator<<(basic_ostream<_CharT, _Traits>& __os,
2902               const discard_block_engine<_Eng, _Pp, _Rp>& __x);
2903
2904    template <class _CharT, class _Traits,
2905              class _Eng, size_t _Pp, size_t _Rp>
2906    friend
2907    basic_istream<_CharT, _Traits>&
2908    operator>>(basic_istream<_CharT, _Traits>& __is,
2909               discard_block_engine<_Eng, _Pp, _Rp>& __x);
2910};
2911
2912template<class _Engine, size_t __p, size_t __r>
2913    _LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::block_size;
2914
2915template<class _Engine, size_t __p, size_t __r>
2916    _LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::used_block;
2917
2918template<class _Engine, size_t __p, size_t __r>
2919typename discard_block_engine<_Engine, __p, __r>::result_type
2920discard_block_engine<_Engine, __p, __r>::operator()()
2921{
2922    if (__n_ >= static_cast<int>(__r))
2923    {
2924        __e_.discard(__p - __r);
2925        __n_ = 0;
2926    }
2927    ++__n_;
2928    return __e_();
2929}
2930
2931template<class _Eng, size_t _Pp, size_t _Rp>
2932inline _LIBCPP_INLINE_VISIBILITY
2933bool
2934operator==(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2935           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
2936{
2937    return __x.__n_ == __y.__n_ && __x.__e_ == __y.__e_;
2938}
2939
2940template<class _Eng, size_t _Pp, size_t _Rp>
2941inline _LIBCPP_INLINE_VISIBILITY
2942bool
2943operator!=(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2944           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
2945{
2946    return !(__x == __y);
2947}
2948
2949template <class _CharT, class _Traits,
2950          class _Eng, size_t _Pp, size_t _Rp>
2951basic_ostream<_CharT, _Traits>&
2952operator<<(basic_ostream<_CharT, _Traits>& __os,
2953           const discard_block_engine<_Eng, _Pp, _Rp>& __x)
2954{
2955    __save_flags<_CharT, _Traits> __lx(__os);
2956    __os.flags(ios_base::dec | ios_base::left);
2957    _CharT __sp = __os.widen(' ');
2958    __os.fill(__sp);
2959    return __os << __x.__e_ << __sp << __x.__n_;
2960}
2961
2962template <class _CharT, class _Traits,
2963          class _Eng, size_t _Pp, size_t _Rp>
2964basic_istream<_CharT, _Traits>&
2965operator>>(basic_istream<_CharT, _Traits>& __is,
2966           discard_block_engine<_Eng, _Pp, _Rp>& __x)
2967{
2968    __save_flags<_CharT, _Traits> __lx(__is);
2969    __is.flags(ios_base::dec | ios_base::skipws);
2970    _Eng __e;
2971    int __n;
2972    __is >> __e >> __n;
2973    if (!__is.fail())
2974    {
2975        __x.__e_ = __e;
2976        __x.__n_ = __n;
2977    }
2978    return __is;
2979}
2980
2981typedef discard_block_engine<ranlux24_base, 223, 23> ranlux24;
2982typedef discard_block_engine<ranlux48_base, 389, 11> ranlux48;
2983
2984// independent_bits_engine
2985
2986template<class _Engine, size_t __w, class _UIntType>
2987class _LIBCPP_TEMPLATE_VIS independent_bits_engine
2988{
2989    template <class _UI, _UI _R0, size_t _Wp, size_t _Mp>
2990    class __get_n
2991    {
2992        static _LIBCPP_CONSTEXPR const size_t _Dt = numeric_limits<_UI>::digits;
2993        static _LIBCPP_CONSTEXPR const size_t _Np = _Wp / _Mp + (_Wp % _Mp != 0);
2994        static _LIBCPP_CONSTEXPR const size_t _W0 = _Wp / _Np;
2995        static _LIBCPP_CONSTEXPR const _UI _Y0 = _W0 >= _Dt ? 0 : (_R0 >> _W0) << _W0;
2996    public:
2997        static _LIBCPP_CONSTEXPR const size_t value = _R0 - _Y0 > _Y0 / _Np ? _Np + 1 : _Np;
2998    };
2999public:
3000    // types
3001    typedef _UIntType result_type;
3002
3003private:
3004    _Engine __e_;
3005
3006    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
3007    static_assert(  0 <  __w, "independent_bits_engine invalid parameters");
3008    static_assert(__w <= _Dt, "independent_bits_engine invalid parameters");
3009
3010    typedef typename _Engine::result_type _Engine_result_type;
3011    typedef typename conditional
3012        <
3013            sizeof(_Engine_result_type) <= sizeof(result_type),
3014                result_type,
3015                _Engine_result_type
3016        >::type _Working_result_type;
3017#ifdef _LIBCPP_HAS_NO_CONSTEXPR
3018    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
3019                                          + _Working_result_type(1);
3020#else
3021    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
3022                                                            + _Working_result_type(1);
3023#endif
3024    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
3025    static _LIBCPP_CONSTEXPR const size_t __n = __get_n<_Working_result_type, _Rp, __w, __m>::value;
3026    static _LIBCPP_CONSTEXPR const size_t __w0 = __w / __n;
3027    static _LIBCPP_CONSTEXPR const size_t __n0 = __n - __w % __n;
3028    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
3029    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
3030    static _LIBCPP_CONSTEXPR const _Working_result_type __y0 = __w0 >= _WDt ? 0 :
3031                                                               (_Rp >> __w0) << __w0;
3032    static _LIBCPP_CONSTEXPR const _Working_result_type __y1 = __w0 >= _WDt - 1 ? 0 :
3033                                                               (_Rp >> (__w0+1)) << (__w0+1);
3034    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask0 = __w0 > 0 ?
3035                                _Engine_result_type(~0) >> (_EDt - __w0) :
3036                                _Engine_result_type(0);
3037    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask1 = __w0 < _EDt - 1 ?
3038                                _Engine_result_type(~0) >> (_EDt - (__w0 + 1)) :
3039                                _Engine_result_type(~0);
3040public:
3041    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
3042    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
3043                                                      (result_type(1) << __w) - result_type(1);
3044    static_assert(_Min < _Max, "independent_bits_engine invalid parameters");
3045
3046    // engine characteristics
3047    _LIBCPP_INLINE_VISIBILITY
3048    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
3049    _LIBCPP_INLINE_VISIBILITY
3050    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
3051
3052    // constructors and seeding functions
3053    _LIBCPP_INLINE_VISIBILITY
3054    independent_bits_engine() {}
3055    _LIBCPP_INLINE_VISIBILITY
3056    explicit independent_bits_engine(const _Engine& __e)
3057        : __e_(__e) {}
3058#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3059    _LIBCPP_INLINE_VISIBILITY
3060    explicit independent_bits_engine(_Engine&& __e)
3061        : __e_(_VSTD::move(__e)) {}
3062#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
3063    _LIBCPP_INLINE_VISIBILITY
3064    explicit independent_bits_engine(result_type __sd) : __e_(__sd) {}
3065    template<class _Sseq>
3066        _LIBCPP_INLINE_VISIBILITY
3067        explicit independent_bits_engine(_Sseq& __q,
3068        typename enable_if<__is_seed_sequence<_Sseq, independent_bits_engine>::value &&
3069                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
3070         : __e_(__q) {}
3071    _LIBCPP_INLINE_VISIBILITY
3072    void seed() {__e_.seed();}
3073    _LIBCPP_INLINE_VISIBILITY
3074    void seed(result_type __sd) {__e_.seed(__sd);}
3075    template<class _Sseq>
3076        _LIBCPP_INLINE_VISIBILITY
3077        typename enable_if
3078        <
3079            __is_seed_sequence<_Sseq, independent_bits_engine>::value,
3080            void
3081        >::type
3082        seed(_Sseq& __q) {__e_.seed(__q);}
3083
3084    // generating functions
3085    _LIBCPP_INLINE_VISIBILITY
3086    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
3087    _LIBCPP_INLINE_VISIBILITY
3088    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
3089
3090    // property functions
3091    _LIBCPP_INLINE_VISIBILITY
3092    const _Engine& base() const _NOEXCEPT {return __e_;}
3093
3094    template<class _Eng, size_t _Wp, class _UI>
3095    friend
3096    bool
3097    operator==(
3098        const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3099        const independent_bits_engine<_Eng, _Wp, _UI>& __y);
3100
3101    template<class _Eng, size_t _Wp, class _UI>
3102    friend
3103    bool
3104    operator!=(
3105        const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3106        const independent_bits_engine<_Eng, _Wp, _UI>& __y);
3107
3108    template <class _CharT, class _Traits,
3109              class _Eng, size_t _Wp, class _UI>
3110    friend
3111    basic_ostream<_CharT, _Traits>&
3112    operator<<(basic_ostream<_CharT, _Traits>& __os,
3113               const independent_bits_engine<_Eng, _Wp, _UI>& __x);
3114
3115    template <class _CharT, class _Traits,
3116              class _Eng, size_t _Wp, class _UI>
3117    friend
3118    basic_istream<_CharT, _Traits>&
3119    operator>>(basic_istream<_CharT, _Traits>& __is,
3120               independent_bits_engine<_Eng, _Wp, _UI>& __x);
3121
3122private:
3123    _LIBCPP_INLINE_VISIBILITY
3124    result_type __eval(false_type);
3125    result_type __eval(true_type);
3126
3127    template <size_t __count>
3128        _LIBCPP_INLINE_VISIBILITY
3129        static
3130        typename enable_if
3131        <
3132            __count < _Dt,
3133            result_type
3134        >::type
3135        __lshift(result_type __x) {return __x << __count;}
3136
3137    template <size_t __count>
3138        _LIBCPP_INLINE_VISIBILITY
3139        static
3140        typename enable_if
3141        <
3142            (__count >= _Dt),
3143            result_type
3144        >::type
3145        __lshift(result_type) {return result_type(0);}
3146};
3147
3148template<class _Engine, size_t __w, class _UIntType>
3149inline
3150_UIntType
3151independent_bits_engine<_Engine, __w, _UIntType>::__eval(false_type)
3152{
3153    return static_cast<result_type>(__e_() & __mask0);
3154}
3155
3156template<class _Engine, size_t __w, class _UIntType>
3157_UIntType
3158independent_bits_engine<_Engine, __w, _UIntType>::__eval(true_type)
3159{
3160    result_type _Sp = 0;
3161    for (size_t __k = 0; __k < __n0; ++__k)
3162    {
3163        _Engine_result_type __u;
3164        do
3165        {
3166            __u = __e_() - _Engine::min();
3167        } while (__u >= __y0);
3168        _Sp = static_cast<result_type>(__lshift<__w0>(_Sp) + (__u & __mask0));
3169    }
3170    for (size_t __k = __n0; __k < __n; ++__k)
3171    {
3172        _Engine_result_type __u;
3173        do
3174        {
3175            __u = __e_() - _Engine::min();
3176        } while (__u >= __y1);
3177        _Sp = static_cast<result_type>(__lshift<__w0+1>(_Sp) + (__u & __mask1));
3178    }
3179    return _Sp;
3180}
3181
3182template<class _Eng, size_t _Wp, class _UI>
3183inline _LIBCPP_INLINE_VISIBILITY
3184bool
3185operator==(
3186    const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3187    const independent_bits_engine<_Eng, _Wp, _UI>& __y)
3188{
3189    return __x.base() == __y.base();
3190}
3191
3192template<class _Eng, size_t _Wp, class _UI>
3193inline _LIBCPP_INLINE_VISIBILITY
3194bool
3195operator!=(
3196    const independent_bits_engine<_Eng, _Wp, _UI>& __x,
3197    const independent_bits_engine<_Eng, _Wp, _UI>& __y)
3198{
3199    return !(__x == __y);
3200}
3201
3202template <class _CharT, class _Traits,
3203          class _Eng, size_t _Wp, class _UI>
3204basic_ostream<_CharT, _Traits>&
3205operator<<(basic_ostream<_CharT, _Traits>& __os,
3206           const independent_bits_engine<_Eng, _Wp, _UI>& __x)
3207{
3208    return __os << __x.base();
3209}
3210
3211template <class _CharT, class _Traits,
3212          class _Eng, size_t _Wp, class _UI>
3213basic_istream<_CharT, _Traits>&
3214operator>>(basic_istream<_CharT, _Traits>& __is,
3215           independent_bits_engine<_Eng, _Wp, _UI>& __x)
3216{
3217    _Eng __e;
3218    __is >> __e;
3219    if (!__is.fail())
3220        __x.__e_ = __e;
3221    return __is;
3222}
3223
3224// shuffle_order_engine
3225
3226template <uint64_t _Xp, uint64_t _Yp>
3227struct __ugcd
3228{
3229    static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
3230};
3231
3232template <uint64_t _Xp>
3233struct __ugcd<_Xp, 0>
3234{
3235    static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
3236};
3237
3238template <uint64_t _Np, uint64_t _Dp>
3239class __uratio
3240{
3241    static_assert(_Dp != 0, "__uratio divide by 0");
3242    static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
3243public:
3244    static _LIBCPP_CONSTEXPR const uint64_t num = _Np / __gcd;
3245    static _LIBCPP_CONSTEXPR const uint64_t den = _Dp / __gcd;
3246
3247    typedef __uratio<num, den> type;
3248};
3249
3250template<class _Engine, size_t __k>
3251class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
3252{
3253    static_assert(0 < __k, "shuffle_order_engine invalid parameters");
3254public:
3255    // types
3256    typedef typename _Engine::result_type result_type;
3257
3258private:
3259    _Engine __e_;
3260    result_type _V_[__k];
3261    result_type _Y_;
3262
3263public:
3264    // engine characteristics
3265    static _LIBCPP_CONSTEXPR const size_t table_size = __k;
3266
3267#ifdef _LIBCPP_HAS_NO_CONSTEXPR
3268    static const result_type _Min = _Engine::_Min;
3269    static const result_type _Max = _Engine::_Max;
3270#else
3271    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
3272    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
3273#endif
3274    static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
3275    _LIBCPP_INLINE_VISIBILITY
3276    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
3277    _LIBCPP_INLINE_VISIBILITY
3278    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
3279
3280    static _LIBCPP_CONSTEXPR const unsigned long long _Rp = _Max - _Min + 1ull;
3281
3282    // constructors and seeding functions
3283    _LIBCPP_INLINE_VISIBILITY
3284    shuffle_order_engine() {__init();}
3285    _LIBCPP_INLINE_VISIBILITY
3286    explicit shuffle_order_engine(const _Engine& __e)
3287        : __e_(__e) {__init();}
3288#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3289    _LIBCPP_INLINE_VISIBILITY
3290    explicit shuffle_order_engine(_Engine&& __e)
3291        : __e_(_VSTD::move(__e)) {__init();}
3292#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
3293    _LIBCPP_INLINE_VISIBILITY
3294    explicit shuffle_order_engine(result_type __sd) : __e_(__sd) {__init();}
3295    template<class _Sseq>
3296        _LIBCPP_INLINE_VISIBILITY
3297        explicit shuffle_order_engine(_Sseq& __q,
3298        typename enable_if<__is_seed_sequence<_Sseq, shuffle_order_engine>::value &&
3299                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
3300         : __e_(__q) {__init();}
3301    _LIBCPP_INLINE_VISIBILITY
3302    void seed() {__e_.seed(); __init();}
3303    _LIBCPP_INLINE_VISIBILITY
3304    void seed(result_type __sd) {__e_.seed(__sd); __init();}
3305    template<class _Sseq>
3306        _LIBCPP_INLINE_VISIBILITY
3307        typename enable_if
3308        <
3309            __is_seed_sequence<_Sseq, shuffle_order_engine>::value,
3310            void
3311        >::type
3312        seed(_Sseq& __q) {__e_.seed(__q); __init();}
3313
3314    // generating functions
3315    _LIBCPP_INLINE_VISIBILITY
3316    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
3317    _LIBCPP_INLINE_VISIBILITY
3318    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
3319
3320    // property functions
3321    _LIBCPP_INLINE_VISIBILITY
3322    const _Engine& base() const _NOEXCEPT {return __e_;}
3323
3324private:
3325    template<class _Eng, size_t _Kp>
3326    friend
3327    bool
3328    operator==(
3329        const shuffle_order_engine<_Eng, _Kp>& __x,
3330        const shuffle_order_engine<_Eng, _Kp>& __y);
3331
3332    template<class _Eng, size_t _Kp>
3333    friend
3334    bool
3335    operator!=(
3336        const shuffle_order_engine<_Eng, _Kp>& __x,
3337        const shuffle_order_engine<_Eng, _Kp>& __y);
3338
3339    template <class _CharT, class _Traits,
3340              class _Eng, size_t _Kp>
3341    friend
3342    basic_ostream<_CharT, _Traits>&
3343    operator<<(basic_ostream<_CharT, _Traits>& __os,
3344               const shuffle_order_engine<_Eng, _Kp>& __x);
3345
3346    template <class _CharT, class _Traits,
3347              class _Eng, size_t _Kp>
3348    friend
3349    basic_istream<_CharT, _Traits>&
3350    operator>>(basic_istream<_CharT, _Traits>& __is,
3351               shuffle_order_engine<_Eng, _Kp>& __x);
3352
3353    _LIBCPP_INLINE_VISIBILITY
3354    void __init()
3355    {
3356        for (size_t __i = 0; __i < __k; ++__i)
3357            _V_[__i] = __e_();
3358        _Y_ = __e_();
3359    }
3360
3361    _LIBCPP_INLINE_VISIBILITY
3362    result_type __eval(false_type) {return __eval2(integral_constant<bool, __k & 1>());}
3363    _LIBCPP_INLINE_VISIBILITY
3364    result_type __eval(true_type) {return __eval(__uratio<__k, _Rp>());}
3365
3366    _LIBCPP_INLINE_VISIBILITY
3367    result_type __eval2(false_type) {return __eval(__uratio<__k/2, 0x8000000000000000ull>());}
3368    _LIBCPP_INLINE_VISIBILITY
3369    result_type __eval2(true_type) {return __evalf<__k, 0>();}
3370
3371    template <uint64_t _Np, uint64_t _Dp>
3372        _LIBCPP_INLINE_VISIBILITY
3373        typename enable_if
3374        <
3375            (__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)),
3376            result_type
3377        >::type
3378        __eval(__uratio<_Np, _Dp>)
3379            {return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();}
3380
3381    template <uint64_t _Np, uint64_t _Dp>
3382        _LIBCPP_INLINE_VISIBILITY
3383        typename enable_if
3384        <
3385            __uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min),
3386            result_type
3387        >::type
3388        __eval(__uratio<_Np, _Dp>)
3389        {
3390            const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (_Y_ - _Min)
3391                                                   / __uratio<_Np, _Dp>::den);
3392            _Y_ = _V_[__j];
3393            _V_[__j] = __e_();
3394            return _Y_;
3395        }
3396
3397    template <uint64_t __n, uint64_t __d>
3398        _LIBCPP_INLINE_VISIBILITY
3399        result_type __evalf()
3400        {
3401            const double _Fp = __d == 0 ?
3402                __n / (2. * 0x8000000000000000ull) :
3403                __n / (double)__d;
3404            const size_t __j = static_cast<size_t>(_Fp * (_Y_ - _Min));
3405            _Y_ = _V_[__j];
3406            _V_[__j] = __e_();
3407            return _Y_;
3408        }
3409};
3410
3411template<class _Engine, size_t __k>
3412    _LIBCPP_CONSTEXPR const size_t shuffle_order_engine<_Engine, __k>::table_size;
3413
3414template<class _Eng, size_t _Kp>
3415bool
3416operator==(
3417    const shuffle_order_engine<_Eng, _Kp>& __x,
3418    const shuffle_order_engine<_Eng, _Kp>& __y)
3419{
3420    return __x._Y_ == __y._Y_ && _VSTD::equal(__x._V_, __x._V_ + _Kp, __y._V_) &&
3421           __x.__e_ == __y.__e_;
3422}
3423
3424template<class _Eng, size_t _Kp>
3425inline _LIBCPP_INLINE_VISIBILITY
3426bool
3427operator!=(
3428    const shuffle_order_engine<_Eng, _Kp>& __x,
3429    const shuffle_order_engine<_Eng, _Kp>& __y)
3430{
3431    return !(__x == __y);
3432}
3433
3434template <class _CharT, class _Traits,
3435          class _Eng, size_t _Kp>
3436basic_ostream<_CharT, _Traits>&
3437operator<<(basic_ostream<_CharT, _Traits>& __os,
3438           const shuffle_order_engine<_Eng, _Kp>& __x)
3439{
3440    __save_flags<_CharT, _Traits> __lx(__os);
3441    __os.flags(ios_base::dec | ios_base::left);
3442    _CharT __sp = __os.widen(' ');
3443    __os.fill(__sp);
3444    __os << __x.__e_ << __sp << __x._V_[0];
3445    for (size_t __i = 1; __i < _Kp; ++__i)
3446        __os << __sp << __x._V_[__i];
3447    return __os << __sp << __x._Y_;
3448}
3449
3450template <class _CharT, class _Traits,
3451          class _Eng, size_t _Kp>
3452basic_istream<_CharT, _Traits>&
3453operator>>(basic_istream<_CharT, _Traits>& __is,
3454           shuffle_order_engine<_Eng, _Kp>& __x)
3455{
3456    typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
3457    __save_flags<_CharT, _Traits> __lx(__is);
3458    __is.flags(ios_base::dec | ios_base::skipws);
3459    _Eng __e;
3460    result_type _Vp[_Kp+1];
3461    __is >> __e;
3462    for (size_t __i = 0; __i < _Kp+1; ++__i)
3463        __is >> _Vp[__i];
3464    if (!__is.fail())
3465    {
3466        __x.__e_ = __e;
3467        for (size_t __i = 0; __i < _Kp; ++__i)
3468            __x._V_[__i] = _Vp[__i];
3469        __x._Y_ = _Vp[_Kp];
3470    }
3471    return __is;
3472}
3473
3474typedef shuffle_order_engine<minstd_rand0, 256>                         knuth_b;
3475
3476// random_device
3477
3478class _LIBCPP_TYPE_VIS random_device
3479{
3480#ifdef _LIBCPP_USING_DEV_RANDOM
3481    int __f_;
3482#endif // defined(_LIBCPP_USING_DEV_RANDOM)
3483public:
3484    // types
3485    typedef unsigned result_type;
3486
3487    // generator characteristics
3488    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
3489    static _LIBCPP_CONSTEXPR const result_type _Max = 0xFFFFFFFFu;
3490
3491    _LIBCPP_INLINE_VISIBILITY
3492    static _LIBCPP_CONSTEXPR result_type min() { return _Min;}
3493    _LIBCPP_INLINE_VISIBILITY
3494    static _LIBCPP_CONSTEXPR result_type max() { return _Max;}
3495
3496    // constructors
3497    explicit random_device(const string& __token = "/dev/urandom");
3498    ~random_device();
3499
3500    // generating functions
3501    result_type operator()();
3502
3503    // property functions
3504    double entropy() const _NOEXCEPT;
3505
3506private:
3507    // no copy functions
3508    random_device(const random_device&); // = delete;
3509    random_device& operator=(const random_device&); // = delete;
3510};
3511
3512// seed_seq
3513
3514class _LIBCPP_TEMPLATE_VIS seed_seq
3515{
3516public:
3517    // types
3518    typedef uint32_t result_type;
3519
3520private:
3521    vector<result_type> __v_;
3522
3523    template<class _InputIterator>
3524        void init(_InputIterator __first, _InputIterator __last);
3525public:
3526    // constructors
3527    _LIBCPP_INLINE_VISIBILITY
3528    seed_seq() _NOEXCEPT {}
3529#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
3530    template<class _Tp>
3531        _LIBCPP_INLINE_VISIBILITY
3532        seed_seq(initializer_list<_Tp> __il) {init(__il.begin(), __il.end());}
3533#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
3534
3535    template<class _InputIterator>
3536        _LIBCPP_INLINE_VISIBILITY
3537        seed_seq(_InputIterator __first, _InputIterator __last)
3538             {init(__first, __last);}
3539
3540    // generating functions
3541    template<class _RandomAccessIterator>
3542        void generate(_RandomAccessIterator __first, _RandomAccessIterator __last);
3543
3544    // property functions
3545    _LIBCPP_INLINE_VISIBILITY
3546    size_t size() const _NOEXCEPT {return __v_.size();}
3547    template<class _OutputIterator>
3548        _LIBCPP_INLINE_VISIBILITY
3549        void param(_OutputIterator __dest) const
3550            {_VSTD::copy(__v_.begin(), __v_.end(), __dest);}
3551
3552private:
3553    // no copy functions
3554    seed_seq(const seed_seq&); // = delete;
3555    void operator=(const seed_seq&); // = delete;
3556
3557    _LIBCPP_INLINE_VISIBILITY
3558    static result_type _Tp(result_type __x) {return __x ^ (__x >> 27);}
3559};
3560
3561template<class _InputIterator>
3562void
3563seed_seq::init(_InputIterator __first, _InputIterator __last)
3564{
3565    for (_InputIterator __s = __first; __s != __last; ++__s)
3566        __v_.push_back(*__s & 0xFFFFFFFF);
3567}
3568
3569template<class _RandomAccessIterator>
3570void
3571seed_seq::generate(_RandomAccessIterator __first, _RandomAccessIterator __last)
3572{
3573    if (__first != __last)
3574    {
3575        _VSTD::fill(__first, __last, 0x8b8b8b8b);
3576        const size_t __n = static_cast<size_t>(__last - __first);
3577        const size_t __s = __v_.size();
3578        const size_t __t = (__n >= 623) ? 11
3579                         : (__n >= 68) ? 7
3580                         : (__n >= 39) ? 5
3581                         : (__n >= 7)  ? 3
3582                         : (__n - 1) / 2;
3583        const size_t __p = (__n - __t) / 2;
3584        const size_t __q = __p + __t;
3585        const size_t __m = _VSTD::max(__s + 1, __n);
3586        // __k = 0;
3587        {
3588            result_type __r = 1664525 * _Tp(__first[0] ^ __first[__p]
3589                                                      ^  __first[__n - 1]);
3590            __first[__p] += __r;
3591            __r += __s;
3592            __first[__q] += __r;
3593            __first[0] = __r;
3594        }
3595        for (size_t __k = 1; __k <= __s; ++__k)
3596        {
3597            const size_t __kmodn = __k % __n;
3598            const size_t __kpmodn = (__k + __p) % __n;
3599            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
3600                                           ^ __first[(__k - 1) % __n]);
3601            __first[__kpmodn] += __r;
3602            __r +=  __kmodn + __v_[__k-1];
3603            __first[(__k + __q) % __n] += __r;
3604            __first[__kmodn] = __r;
3605        }
3606        for (size_t __k = __s + 1; __k < __m; ++__k)
3607        {
3608            const size_t __kmodn = __k % __n;
3609            const size_t __kpmodn = (__k + __p) % __n;
3610            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
3611                                           ^ __first[(__k - 1) % __n]);
3612            __first[__kpmodn] += __r;
3613            __r +=  __kmodn;
3614            __first[(__k + __q) % __n] += __r;
3615            __first[__kmodn] = __r;
3616        }
3617        for (size_t __k = __m; __k < __m + __n; ++__k)
3618        {
3619            const size_t __kmodn = __k % __n;
3620            const size_t __kpmodn = (__k + __p) % __n;
3621            result_type __r = 1566083941 * _Tp(__first[__kmodn] +
3622                                              __first[__kpmodn] +
3623                                              __first[(__k - 1) % __n]);
3624            __first[__kpmodn] ^= __r;
3625            __r -= __kmodn;
3626            __first[(__k + __q) % __n] ^= __r;
3627            __first[__kmodn] = __r;
3628        }
3629    }
3630}
3631
3632// generate_canonical
3633
3634template<class _RealType, size_t __bits, class _URNG>
3635_RealType
3636generate_canonical(_URNG& __g)
3637{
3638    const size_t _Dt = numeric_limits<_RealType>::digits;
3639    const size_t __b = _Dt < __bits ? _Dt : __bits;
3640#ifdef _LIBCPP_HAS_NO_CONSTEXPR
3641    const size_t __logR = __log2<uint64_t, _URNG::_Max - _URNG::_Min + uint64_t(1)>::value;
3642#else
3643    const size_t __logR = __log2<uint64_t, _URNG::max() - _URNG::min() + uint64_t(1)>::value;
3644#endif
3645    const size_t __k = __b / __logR + (__b % __logR != 0) + (__b == 0);
3646    const _RealType _Rp = _URNG::max() - _URNG::min() + _RealType(1);
3647    _RealType __base = _Rp;
3648    _RealType _Sp = __g() - _URNG::min();
3649    for (size_t __i = 1; __i < __k; ++__i, __base *= _Rp)
3650        _Sp += (__g() - _URNG::min()) * __base;
3651    return _Sp / __base;
3652}
3653
3654// uniform_int_distribution
3655
3656// in <algorithm>
3657
3658template <class _CharT, class _Traits, class _IT>
3659basic_ostream<_CharT, _Traits>&
3660operator<<(basic_ostream<_CharT, _Traits>& __os,
3661           const uniform_int_distribution<_IT>& __x)
3662{
3663    __save_flags<_CharT, _Traits> __lx(__os);
3664    __os.flags(ios_base::dec | ios_base::left);
3665    _CharT __sp = __os.widen(' ');
3666    __os.fill(__sp);
3667    return __os << __x.a() << __sp << __x.b();
3668}
3669
3670template <class _CharT, class _Traits, class _IT>
3671basic_istream<_CharT, _Traits>&
3672operator>>(basic_istream<_CharT, _Traits>& __is,
3673           uniform_int_distribution<_IT>& __x)
3674{
3675    typedef uniform_int_distribution<_IT> _Eng;
3676    typedef typename _Eng::result_type result_type;
3677    typedef typename _Eng::param_type param_type;
3678    __save_flags<_CharT, _Traits> __lx(__is);
3679    __is.flags(ios_base::dec | ios_base::skipws);
3680    result_type __a;
3681    result_type __b;
3682    __is >> __a >> __b;
3683    if (!__is.fail())
3684        __x.param(param_type(__a, __b));
3685    return __is;
3686}
3687
3688// uniform_real_distribution
3689
3690template<class _RealType = double>
3691class _LIBCPP_TEMPLATE_VIS uniform_real_distribution
3692{
3693public:
3694    // types
3695    typedef _RealType result_type;
3696
3697    class _LIBCPP_TEMPLATE_VIS param_type
3698    {
3699        result_type __a_;
3700        result_type __b_;
3701    public:
3702        typedef uniform_real_distribution distribution_type;
3703
3704        _LIBCPP_INLINE_VISIBILITY
3705        explicit param_type(result_type __a = 0,
3706                            result_type __b = 1)
3707            : __a_(__a), __b_(__b) {}
3708
3709        _LIBCPP_INLINE_VISIBILITY
3710        result_type a() const {return __a_;}
3711        _LIBCPP_INLINE_VISIBILITY
3712        result_type b() const {return __b_;}
3713
3714        friend _LIBCPP_INLINE_VISIBILITY
3715        bool operator==(const param_type& __x, const param_type& __y)
3716            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
3717        friend _LIBCPP_INLINE_VISIBILITY
3718        bool operator!=(const param_type& __x, const param_type& __y)
3719            {return !(__x == __y);}
3720    };
3721
3722private:
3723    param_type __p_;
3724
3725public:
3726    // constructors and reset functions
3727    _LIBCPP_INLINE_VISIBILITY
3728    explicit uniform_real_distribution(result_type __a = 0, result_type __b = 1)
3729        : __p_(param_type(__a, __b)) {}
3730    _LIBCPP_INLINE_VISIBILITY
3731    explicit uniform_real_distribution(const param_type& __p) : __p_(__p) {}
3732    _LIBCPP_INLINE_VISIBILITY
3733    void reset() {}
3734
3735    // generating functions
3736    template<class _URNG>
3737        _LIBCPP_INLINE_VISIBILITY
3738        result_type operator()(_URNG& __g)
3739        {return (*this)(__g, __p_);}
3740    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
3741
3742    // property functions
3743    _LIBCPP_INLINE_VISIBILITY
3744    result_type a() const {return __p_.a();}
3745    _LIBCPP_INLINE_VISIBILITY
3746    result_type b() const {return __p_.b();}
3747
3748    _LIBCPP_INLINE_VISIBILITY
3749    param_type param() const {return __p_;}
3750    _LIBCPP_INLINE_VISIBILITY
3751    void param(const param_type& __p) {__p_ = __p;}
3752
3753    _LIBCPP_INLINE_VISIBILITY
3754    result_type min() const {return a();}
3755    _LIBCPP_INLINE_VISIBILITY
3756    result_type max() const {return b();}
3757
3758    friend _LIBCPP_INLINE_VISIBILITY
3759        bool operator==(const uniform_real_distribution& __x,
3760                        const uniform_real_distribution& __y)
3761        {return __x.__p_ == __y.__p_;}
3762    friend _LIBCPP_INLINE_VISIBILITY
3763        bool operator!=(const uniform_real_distribution& __x,
3764                        const uniform_real_distribution& __y)
3765        {return !(__x == __y);}
3766};
3767
3768template<class _RealType>
3769template<class _URNG>
3770inline
3771typename uniform_real_distribution<_RealType>::result_type
3772uniform_real_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
3773{
3774    return (__p.b() - __p.a())
3775        * _VSTD::generate_canonical<_RealType, numeric_limits<_RealType>::digits>(__g)
3776        + __p.a();
3777}
3778
3779template <class _CharT, class _Traits, class _RT>
3780basic_ostream<_CharT, _Traits>&
3781operator<<(basic_ostream<_CharT, _Traits>& __os,
3782           const uniform_real_distribution<_RT>& __x)
3783{
3784    __save_flags<_CharT, _Traits> __lx(__os);
3785    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
3786               ios_base::scientific);
3787    _CharT __sp = __os.widen(' ');
3788    __os.fill(__sp);
3789    return __os << __x.a() << __sp << __x.b();
3790}
3791
3792template <class _CharT, class _Traits, class _RT>
3793basic_istream<_CharT, _Traits>&
3794operator>>(basic_istream<_CharT, _Traits>& __is,
3795           uniform_real_distribution<_RT>& __x)
3796{
3797    typedef uniform_real_distribution<_RT> _Eng;
3798    typedef typename _Eng::result_type result_type;
3799    typedef typename _Eng::param_type param_type;
3800    __save_flags<_CharT, _Traits> __lx(__is);
3801    __is.flags(ios_base::dec | ios_base::skipws);
3802    result_type __a;
3803    result_type __b;
3804    __is >> __a >> __b;
3805    if (!__is.fail())
3806        __x.param(param_type(__a, __b));
3807    return __is;
3808}
3809
3810// bernoulli_distribution
3811
3812class _LIBCPP_TEMPLATE_VIS bernoulli_distribution
3813{
3814public:
3815    // types
3816    typedef bool result_type;
3817
3818    class _LIBCPP_TEMPLATE_VIS param_type
3819    {
3820        double __p_;
3821    public:
3822        typedef bernoulli_distribution distribution_type;
3823
3824        _LIBCPP_INLINE_VISIBILITY
3825        explicit param_type(double __p = 0.5) : __p_(__p) {}
3826
3827        _LIBCPP_INLINE_VISIBILITY
3828        double p() const {return __p_;}
3829
3830        friend _LIBCPP_INLINE_VISIBILITY
3831            bool operator==(const param_type& __x, const param_type& __y)
3832            {return __x.__p_ == __y.__p_;}
3833        friend _LIBCPP_INLINE_VISIBILITY
3834            bool operator!=(const param_type& __x, const param_type& __y)
3835            {return !(__x == __y);}
3836    };
3837
3838private:
3839    param_type __p_;
3840
3841public:
3842    // constructors and reset functions
3843    _LIBCPP_INLINE_VISIBILITY
3844    explicit bernoulli_distribution(double __p = 0.5)
3845        : __p_(param_type(__p)) {}
3846    _LIBCPP_INLINE_VISIBILITY
3847    explicit bernoulli_distribution(const param_type& __p) : __p_(__p) {}
3848    _LIBCPP_INLINE_VISIBILITY
3849    void reset() {}
3850
3851    // generating functions
3852    template<class _URNG>
3853        _LIBCPP_INLINE_VISIBILITY
3854        result_type operator()(_URNG& __g)
3855        {return (*this)(__g, __p_);}
3856    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
3857
3858    // property functions
3859    _LIBCPP_INLINE_VISIBILITY
3860    double p() const {return __p_.p();}
3861
3862    _LIBCPP_INLINE_VISIBILITY
3863    param_type param() const {return __p_;}
3864    _LIBCPP_INLINE_VISIBILITY
3865    void param(const param_type& __p) {__p_ = __p;}
3866
3867    _LIBCPP_INLINE_VISIBILITY
3868    result_type min() const {return false;}
3869    _LIBCPP_INLINE_VISIBILITY
3870    result_type max() const {return true;}
3871
3872    friend _LIBCPP_INLINE_VISIBILITY
3873        bool operator==(const bernoulli_distribution& __x,
3874                        const bernoulli_distribution& __y)
3875        {return __x.__p_ == __y.__p_;}
3876    friend _LIBCPP_INLINE_VISIBILITY
3877        bool operator!=(const bernoulli_distribution& __x,
3878                        const bernoulli_distribution& __y)
3879        {return !(__x == __y);}
3880};
3881
3882template<class _URNG>
3883inline
3884bernoulli_distribution::result_type
3885bernoulli_distribution::operator()(_URNG& __g, const param_type& __p)
3886{
3887    uniform_real_distribution<double> __gen;
3888    return __gen(__g) < __p.p();
3889}
3890
3891template <class _CharT, class _Traits>
3892basic_ostream<_CharT, _Traits>&
3893operator<<(basic_ostream<_CharT, _Traits>& __os, const bernoulli_distribution& __x)
3894{
3895    __save_flags<_CharT, _Traits> __lx(__os);
3896    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
3897               ios_base::scientific);
3898    _CharT __sp = __os.widen(' ');
3899    __os.fill(__sp);
3900    return __os << __x.p();
3901}
3902
3903template <class _CharT, class _Traits>
3904basic_istream<_CharT, _Traits>&
3905operator>>(basic_istream<_CharT, _Traits>& __is, bernoulli_distribution& __x)
3906{
3907    typedef bernoulli_distribution _Eng;
3908    typedef typename _Eng::param_type param_type;
3909    __save_flags<_CharT, _Traits> __lx(__is);
3910    __is.flags(ios_base::dec | ios_base::skipws);
3911    double __p;
3912    __is >> __p;
3913    if (!__is.fail())
3914        __x.param(param_type(__p));
3915    return __is;
3916}
3917
3918// binomial_distribution
3919
3920template<class _IntType = int>
3921class _LIBCPP_TEMPLATE_VIS binomial_distribution
3922{
3923public:
3924    // types
3925    typedef _IntType result_type;
3926
3927    class _LIBCPP_TEMPLATE_VIS param_type
3928    {
3929        result_type __t_;
3930        double __p_;
3931        double __pr_;
3932        double __odds_ratio_;
3933        result_type __r0_;
3934    public:
3935        typedef binomial_distribution distribution_type;
3936
3937        explicit param_type(result_type __t = 1, double __p = 0.5);
3938
3939        _LIBCPP_INLINE_VISIBILITY
3940        result_type t() const {return __t_;}
3941        _LIBCPP_INLINE_VISIBILITY
3942        double p() const {return __p_;}
3943
3944        friend _LIBCPP_INLINE_VISIBILITY
3945            bool operator==(const param_type& __x, const param_type& __y)
3946            {return __x.__t_ == __y.__t_ && __x.__p_ == __y.__p_;}
3947        friend _LIBCPP_INLINE_VISIBILITY
3948            bool operator!=(const param_type& __x, const param_type& __y)
3949            {return !(__x == __y);}
3950
3951        friend class binomial_distribution;
3952    };
3953
3954private:
3955    param_type __p_;
3956
3957public:
3958    // constructors and reset functions
3959    _LIBCPP_INLINE_VISIBILITY
3960    explicit binomial_distribution(result_type __t = 1, double __p = 0.5)
3961        : __p_(param_type(__t, __p)) {}
3962    _LIBCPP_INLINE_VISIBILITY
3963    explicit binomial_distribution(const param_type& __p) : __p_(__p) {}
3964    _LIBCPP_INLINE_VISIBILITY
3965    void reset() {}
3966
3967    // generating functions
3968    template<class _URNG>
3969        _LIBCPP_INLINE_VISIBILITY
3970        result_type operator()(_URNG& __g)
3971        {return (*this)(__g, __p_);}
3972    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3973
3974    // property functions
3975    _LIBCPP_INLINE_VISIBILITY
3976    result_type t() const {return __p_.t();}
3977    _LIBCPP_INLINE_VISIBILITY
3978    double p() const {return __p_.p();}
3979
3980    _LIBCPP_INLINE_VISIBILITY
3981    param_type param() const {return __p_;}
3982    _LIBCPP_INLINE_VISIBILITY
3983    void param(const param_type& __p) {__p_ = __p;}
3984
3985    _LIBCPP_INLINE_VISIBILITY
3986    result_type min() const {return 0;}
3987    _LIBCPP_INLINE_VISIBILITY
3988    result_type max() const {return t();}
3989
3990    friend _LIBCPP_INLINE_VISIBILITY
3991        bool operator==(const binomial_distribution& __x,
3992                        const binomial_distribution& __y)
3993        {return __x.__p_ == __y.__p_;}
3994    friend _LIBCPP_INLINE_VISIBILITY
3995        bool operator!=(const binomial_distribution& __x,
3996                        const binomial_distribution& __y)
3997        {return !(__x == __y);}
3998};
3999
4000template<class _IntType>
4001binomial_distribution<_IntType>::param_type::param_type(result_type __t, double __p)
4002    : __t_(__t), __p_(__p)
4003{
4004    if (0 < __p_ && __p_ < 1)
4005    {
4006        __r0_ = static_cast<result_type>((__t_ + 1) * __p_);
4007        __pr_ = _VSTD::exp(_VSTD::lgamma(__t_ + 1.) - _VSTD::lgamma(__r0_ + 1.) -
4008                          _VSTD::lgamma(__t_ - __r0_ + 1.) + __r0_ * _VSTD::log(__p_) +
4009                          (__t_ - __r0_) * _VSTD::log(1 - __p_));
4010        __odds_ratio_ = __p_ / (1 - __p_);
4011    }
4012}
4013
4014// Reference: Kemp, C.D. (1986). `A modal method for generating binomial
4015//           variables', Commun. Statist. - Theor. Meth. 15(3), 805-813.
4016template<class _IntType>
4017template<class _URNG>
4018_IntType
4019binomial_distribution<_IntType>::operator()(_URNG& __g, const param_type& __pr)
4020{
4021    if (__pr.__t_ == 0 || __pr.__p_ == 0)
4022        return 0;
4023    if (__pr.__p_ == 1)
4024        return __pr.__t_;
4025    uniform_real_distribution<double> __gen;
4026    double __u = __gen(__g) - __pr.__pr_;
4027    if (__u < 0)
4028        return __pr.__r0_;
4029    double __pu = __pr.__pr_;
4030    double __pd = __pu;
4031    result_type __ru = __pr.__r0_;
4032    result_type __rd = __ru;
4033    while (true)
4034    {
4035        if (__rd >= 1)
4036        {
4037            __pd *= __rd / (__pr.__odds_ratio_ * (__pr.__t_ - __rd + 1));
4038            __u -= __pd;
4039            if (__u < 0)
4040                return __rd - 1;
4041        }
4042        if ( __rd != 0 )
4043            --__rd;
4044        ++__ru;
4045        if (__ru <= __pr.__t_)
4046        {
4047            __pu *= (__pr.__t_ - __ru + 1) * __pr.__odds_ratio_ / __ru;
4048            __u -= __pu;
4049            if (__u < 0)
4050                return __ru;
4051        }
4052    }
4053}
4054
4055template <class _CharT, class _Traits, class _IntType>
4056basic_ostream<_CharT, _Traits>&
4057operator<<(basic_ostream<_CharT, _Traits>& __os,
4058           const binomial_distribution<_IntType>& __x)
4059{
4060    __save_flags<_CharT, _Traits> __lx(__os);
4061    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4062               ios_base::scientific);
4063    _CharT __sp = __os.widen(' ');
4064    __os.fill(__sp);
4065    return __os << __x.t() << __sp << __x.p();
4066}
4067
4068template <class _CharT, class _Traits, class _IntType>
4069basic_istream<_CharT, _Traits>&
4070operator>>(basic_istream<_CharT, _Traits>& __is,
4071           binomial_distribution<_IntType>& __x)
4072{
4073    typedef binomial_distribution<_IntType> _Eng;
4074    typedef typename _Eng::result_type result_type;
4075    typedef typename _Eng::param_type param_type;
4076    __save_flags<_CharT, _Traits> __lx(__is);
4077    __is.flags(ios_base::dec | ios_base::skipws);
4078    result_type __t;
4079    double __p;
4080    __is >> __t >> __p;
4081    if (!__is.fail())
4082        __x.param(param_type(__t, __p));
4083    return __is;
4084}
4085
4086// exponential_distribution
4087
4088template<class _RealType = double>
4089class _LIBCPP_TEMPLATE_VIS exponential_distribution
4090{
4091public:
4092    // types
4093    typedef _RealType result_type;
4094
4095    class _LIBCPP_TEMPLATE_VIS param_type
4096    {
4097        result_type __lambda_;
4098    public:
4099        typedef exponential_distribution distribution_type;
4100
4101        _LIBCPP_INLINE_VISIBILITY
4102        explicit param_type(result_type __lambda = 1) : __lambda_(__lambda) {}
4103
4104        _LIBCPP_INLINE_VISIBILITY
4105        result_type lambda() const {return __lambda_;}
4106
4107        friend _LIBCPP_INLINE_VISIBILITY
4108            bool operator==(const param_type& __x, const param_type& __y)
4109            {return __x.__lambda_ == __y.__lambda_;}
4110        friend _LIBCPP_INLINE_VISIBILITY
4111            bool operator!=(const param_type& __x, const param_type& __y)
4112            {return !(__x == __y);}
4113    };
4114
4115private:
4116    param_type __p_;
4117
4118public:
4119    // constructors and reset functions
4120    _LIBCPP_INLINE_VISIBILITY
4121    explicit exponential_distribution(result_type __lambda = 1)
4122        : __p_(param_type(__lambda)) {}
4123    _LIBCPP_INLINE_VISIBILITY
4124    explicit exponential_distribution(const param_type& __p) : __p_(__p) {}
4125    _LIBCPP_INLINE_VISIBILITY
4126    void reset() {}
4127
4128    // generating functions
4129    template<class _URNG>
4130        _LIBCPP_INLINE_VISIBILITY
4131        result_type operator()(_URNG& __g)
4132        {return (*this)(__g, __p_);}
4133    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4134
4135    // property functions
4136    _LIBCPP_INLINE_VISIBILITY
4137    result_type lambda() const {return __p_.lambda();}
4138
4139    _LIBCPP_INLINE_VISIBILITY
4140    param_type param() const {return __p_;}
4141    _LIBCPP_INLINE_VISIBILITY
4142    void param(const param_type& __p) {__p_ = __p;}
4143
4144    _LIBCPP_INLINE_VISIBILITY
4145    result_type min() const {return 0;}
4146    _LIBCPP_INLINE_VISIBILITY
4147    result_type max() const {return numeric_limits<result_type>::infinity();}
4148
4149    friend _LIBCPP_INLINE_VISIBILITY
4150        bool operator==(const exponential_distribution& __x,
4151                        const exponential_distribution& __y)
4152        {return __x.__p_ == __y.__p_;}
4153    friend _LIBCPP_INLINE_VISIBILITY
4154        bool operator!=(const exponential_distribution& __x,
4155                        const exponential_distribution& __y)
4156        {return !(__x == __y);}
4157};
4158
4159template <class _RealType>
4160template<class _URNG>
4161_RealType
4162exponential_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4163{
4164    return -_VSTD::log
4165                  (
4166                      result_type(1) -
4167                      _VSTD::generate_canonical<result_type,
4168                                       numeric_limits<result_type>::digits>(__g)
4169                  )
4170                  / __p.lambda();
4171}
4172
4173template <class _CharT, class _Traits, class _RealType>
4174basic_ostream<_CharT, _Traits>&
4175operator<<(basic_ostream<_CharT, _Traits>& __os,
4176           const exponential_distribution<_RealType>& __x)
4177{
4178    __save_flags<_CharT, _Traits> __lx(__os);
4179    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4180               ios_base::scientific);
4181    return __os << __x.lambda();
4182}
4183
4184template <class _CharT, class _Traits, class _RealType>
4185basic_istream<_CharT, _Traits>&
4186operator>>(basic_istream<_CharT, _Traits>& __is,
4187           exponential_distribution<_RealType>& __x)
4188{
4189    typedef exponential_distribution<_RealType> _Eng;
4190    typedef typename _Eng::result_type result_type;
4191    typedef typename _Eng::param_type param_type;
4192    __save_flags<_CharT, _Traits> __lx(__is);
4193    __is.flags(ios_base::dec | ios_base::skipws);
4194    result_type __lambda;
4195    __is >> __lambda;
4196    if (!__is.fail())
4197        __x.param(param_type(__lambda));
4198    return __is;
4199}
4200
4201// normal_distribution
4202
4203template<class _RealType = double>
4204class _LIBCPP_TEMPLATE_VIS normal_distribution
4205{
4206public:
4207    // types
4208    typedef _RealType result_type;
4209
4210    class _LIBCPP_TEMPLATE_VIS param_type
4211    {
4212        result_type __mean_;
4213        result_type __stddev_;
4214    public:
4215        typedef normal_distribution distribution_type;
4216
4217        _LIBCPP_INLINE_VISIBILITY
4218        explicit param_type(result_type __mean = 0, result_type __stddev = 1)
4219            : __mean_(__mean), __stddev_(__stddev) {}
4220
4221        _LIBCPP_INLINE_VISIBILITY
4222        result_type mean() const {return __mean_;}
4223        _LIBCPP_INLINE_VISIBILITY
4224        result_type stddev() const {return __stddev_;}
4225
4226        friend _LIBCPP_INLINE_VISIBILITY
4227            bool operator==(const param_type& __x, const param_type& __y)
4228            {return __x.__mean_ == __y.__mean_ && __x.__stddev_ == __y.__stddev_;}
4229        friend _LIBCPP_INLINE_VISIBILITY
4230            bool operator!=(const param_type& __x, const param_type& __y)
4231            {return !(__x == __y);}
4232    };
4233
4234private:
4235    param_type __p_;
4236    result_type _V_;
4237    bool _V_hot_;
4238
4239public:
4240    // constructors and reset functions
4241    _LIBCPP_INLINE_VISIBILITY
4242    explicit normal_distribution(result_type __mean = 0, result_type __stddev = 1)
4243        : __p_(param_type(__mean, __stddev)), _V_hot_(false) {}
4244    _LIBCPP_INLINE_VISIBILITY
4245    explicit normal_distribution(const param_type& __p)
4246        : __p_(__p), _V_hot_(false) {}
4247    _LIBCPP_INLINE_VISIBILITY
4248    void reset() {_V_hot_ = false;}
4249
4250    // generating functions
4251    template<class _URNG>
4252        _LIBCPP_INLINE_VISIBILITY
4253        result_type operator()(_URNG& __g)
4254        {return (*this)(__g, __p_);}
4255    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4256
4257    // property functions
4258    _LIBCPP_INLINE_VISIBILITY
4259    result_type mean() const {return __p_.mean();}
4260    _LIBCPP_INLINE_VISIBILITY
4261    result_type stddev() const {return __p_.stddev();}
4262
4263    _LIBCPP_INLINE_VISIBILITY
4264    param_type param() const {return __p_;}
4265    _LIBCPP_INLINE_VISIBILITY
4266    void param(const param_type& __p) {__p_ = __p;}
4267
4268    _LIBCPP_INLINE_VISIBILITY
4269    result_type min() const {return -numeric_limits<result_type>::infinity();}
4270    _LIBCPP_INLINE_VISIBILITY
4271    result_type max() const {return numeric_limits<result_type>::infinity();}
4272
4273    friend _LIBCPP_INLINE_VISIBILITY
4274        bool operator==(const normal_distribution& __x,
4275                        const normal_distribution& __y)
4276        {return __x.__p_ == __y.__p_ && __x._V_hot_ == __y._V_hot_ &&
4277                (!__x._V_hot_ || __x._V_ == __y._V_);}
4278    friend _LIBCPP_INLINE_VISIBILITY
4279        bool operator!=(const normal_distribution& __x,
4280                        const normal_distribution& __y)
4281        {return !(__x == __y);}
4282
4283    template <class _CharT, class _Traits, class _RT>
4284    friend
4285    basic_ostream<_CharT, _Traits>&
4286    operator<<(basic_ostream<_CharT, _Traits>& __os,
4287               const normal_distribution<_RT>& __x);
4288
4289    template <class _CharT, class _Traits, class _RT>
4290    friend
4291    basic_istream<_CharT, _Traits>&
4292    operator>>(basic_istream<_CharT, _Traits>& __is,
4293               normal_distribution<_RT>& __x);
4294};
4295
4296template <class _RealType>
4297template<class _URNG>
4298_RealType
4299normal_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4300{
4301    result_type _Up;
4302    if (_V_hot_)
4303    {
4304        _V_hot_ = false;
4305        _Up = _V_;
4306    }
4307    else
4308    {
4309        uniform_real_distribution<result_type> _Uni(-1, 1);
4310        result_type __u;
4311        result_type __v;
4312        result_type __s;
4313        do
4314        {
4315            __u = _Uni(__g);
4316            __v = _Uni(__g);
4317            __s = __u * __u + __v * __v;
4318        } while (__s > 1 || __s == 0);
4319        result_type _Fp = _VSTD::sqrt(-2 * _VSTD::log(__s) / __s);
4320        _V_ = __v * _Fp;
4321        _V_hot_ = true;
4322        _Up = __u * _Fp;
4323    }
4324    return _Up * __p.stddev() + __p.mean();
4325}
4326
4327template <class _CharT, class _Traits, class _RT>
4328basic_ostream<_CharT, _Traits>&
4329operator<<(basic_ostream<_CharT, _Traits>& __os,
4330           const normal_distribution<_RT>& __x)
4331{
4332    __save_flags<_CharT, _Traits> __lx(__os);
4333    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4334               ios_base::scientific);
4335    _CharT __sp = __os.widen(' ');
4336    __os.fill(__sp);
4337    __os << __x.mean() << __sp << __x.stddev() << __sp << __x._V_hot_;
4338    if (__x._V_hot_)
4339        __os << __sp << __x._V_;
4340    return __os;
4341}
4342
4343template <class _CharT, class _Traits, class _RT>
4344basic_istream<_CharT, _Traits>&
4345operator>>(basic_istream<_CharT, _Traits>& __is,
4346           normal_distribution<_RT>& __x)
4347{
4348    typedef normal_distribution<_RT> _Eng;
4349    typedef typename _Eng::result_type result_type;
4350    typedef typename _Eng::param_type param_type;
4351    __save_flags<_CharT, _Traits> __lx(__is);
4352    __is.flags(ios_base::dec | ios_base::skipws);
4353    result_type __mean;
4354    result_type __stddev;
4355    result_type _Vp = 0;
4356    bool _V_hot = false;
4357    __is >> __mean >> __stddev >> _V_hot;
4358    if (_V_hot)
4359        __is >> _Vp;
4360    if (!__is.fail())
4361    {
4362        __x.param(param_type(__mean, __stddev));
4363        __x._V_hot_ = _V_hot;
4364        __x._V_ = _Vp;
4365    }
4366    return __is;
4367}
4368
4369// lognormal_distribution
4370
4371template<class _RealType = double>
4372class _LIBCPP_TEMPLATE_VIS lognormal_distribution
4373{
4374public:
4375    // types
4376    typedef _RealType result_type;
4377
4378    class _LIBCPP_TEMPLATE_VIS param_type
4379    {
4380        normal_distribution<result_type> __nd_;
4381    public:
4382        typedef lognormal_distribution distribution_type;
4383
4384        _LIBCPP_INLINE_VISIBILITY
4385        explicit param_type(result_type __m = 0, result_type __s = 1)
4386            : __nd_(__m, __s) {}
4387
4388        _LIBCPP_INLINE_VISIBILITY
4389        result_type m() const {return __nd_.mean();}
4390        _LIBCPP_INLINE_VISIBILITY
4391        result_type s() const {return __nd_.stddev();}
4392
4393        friend _LIBCPP_INLINE_VISIBILITY
4394            bool operator==(const param_type& __x, const param_type& __y)
4395            {return __x.__nd_ == __y.__nd_;}
4396        friend _LIBCPP_INLINE_VISIBILITY
4397            bool operator!=(const param_type& __x, const param_type& __y)
4398            {return !(__x == __y);}
4399        friend class lognormal_distribution;
4400
4401        template <class _CharT, class _Traits, class _RT>
4402        friend
4403        basic_ostream<_CharT, _Traits>&
4404        operator<<(basic_ostream<_CharT, _Traits>& __os,
4405                   const lognormal_distribution<_RT>& __x);
4406
4407        template <class _CharT, class _Traits, class _RT>
4408        friend
4409        basic_istream<_CharT, _Traits>&
4410        operator>>(basic_istream<_CharT, _Traits>& __is,
4411                   lognormal_distribution<_RT>& __x);
4412    };
4413
4414private:
4415    param_type __p_;
4416
4417public:
4418    // constructor and reset functions
4419    _LIBCPP_INLINE_VISIBILITY
4420    explicit lognormal_distribution(result_type __m = 0, result_type __s = 1)
4421        : __p_(param_type(__m, __s)) {}
4422    _LIBCPP_INLINE_VISIBILITY
4423    explicit lognormal_distribution(const param_type& __p)
4424        : __p_(__p) {}
4425    _LIBCPP_INLINE_VISIBILITY
4426    void reset() {__p_.__nd_.reset();}
4427
4428    // generating functions
4429    template<class _URNG>
4430        _LIBCPP_INLINE_VISIBILITY
4431        result_type operator()(_URNG& __g)
4432        {return (*this)(__g, __p_);}
4433    template<class _URNG>
4434        _LIBCPP_INLINE_VISIBILITY
4435        result_type operator()(_URNG& __g, const param_type& __p)
4436        {return _VSTD::exp(const_cast<normal_distribution<result_type>&>(__p.__nd_)(__g));}
4437
4438    // property functions
4439    _LIBCPP_INLINE_VISIBILITY
4440    result_type m() const {return __p_.m();}
4441    _LIBCPP_INLINE_VISIBILITY
4442    result_type s() const {return __p_.s();}
4443
4444    _LIBCPP_INLINE_VISIBILITY
4445    param_type param() const {return __p_;}
4446    _LIBCPP_INLINE_VISIBILITY
4447    void param(const param_type& __p) {__p_ = __p;}
4448
4449    _LIBCPP_INLINE_VISIBILITY
4450    result_type min() const {return 0;}
4451    _LIBCPP_INLINE_VISIBILITY
4452    result_type max() const {return numeric_limits<result_type>::infinity();}
4453
4454    friend _LIBCPP_INLINE_VISIBILITY
4455        bool operator==(const lognormal_distribution& __x,
4456                        const lognormal_distribution& __y)
4457        {return __x.__p_ == __y.__p_;}
4458    friend _LIBCPP_INLINE_VISIBILITY
4459        bool operator!=(const lognormal_distribution& __x,
4460                        const lognormal_distribution& __y)
4461        {return !(__x == __y);}
4462
4463    template <class _CharT, class _Traits, class _RT>
4464    friend
4465    basic_ostream<_CharT, _Traits>&
4466    operator<<(basic_ostream<_CharT, _Traits>& __os,
4467               const lognormal_distribution<_RT>& __x);
4468
4469    template <class _CharT, class _Traits, class _RT>
4470    friend
4471    basic_istream<_CharT, _Traits>&
4472    operator>>(basic_istream<_CharT, _Traits>& __is,
4473               lognormal_distribution<_RT>& __x);
4474};
4475
4476template <class _CharT, class _Traits, class _RT>
4477inline _LIBCPP_INLINE_VISIBILITY
4478basic_ostream<_CharT, _Traits>&
4479operator<<(basic_ostream<_CharT, _Traits>& __os,
4480           const lognormal_distribution<_RT>& __x)
4481{
4482    return __os << __x.__p_.__nd_;
4483}
4484
4485template <class _CharT, class _Traits, class _RT>
4486inline _LIBCPP_INLINE_VISIBILITY
4487basic_istream<_CharT, _Traits>&
4488operator>>(basic_istream<_CharT, _Traits>& __is,
4489           lognormal_distribution<_RT>& __x)
4490{
4491    return __is >> __x.__p_.__nd_;
4492}
4493
4494// poisson_distribution
4495
4496template<class _IntType = int>
4497class _LIBCPP_TEMPLATE_VIS poisson_distribution
4498{
4499public:
4500    // types
4501    typedef _IntType result_type;
4502
4503    class _LIBCPP_TEMPLATE_VIS param_type
4504    {
4505        double __mean_;
4506        double __s_;
4507        double __d_;
4508        double __l_;
4509        double __omega_;
4510        double __c0_;
4511        double __c1_;
4512        double __c2_;
4513        double __c3_;
4514        double __c_;
4515
4516    public:
4517        typedef poisson_distribution distribution_type;
4518
4519        explicit param_type(double __mean = 1.0);
4520
4521        _LIBCPP_INLINE_VISIBILITY
4522        double mean() const {return __mean_;}
4523
4524        friend _LIBCPP_INLINE_VISIBILITY
4525            bool operator==(const param_type& __x, const param_type& __y)
4526            {return __x.__mean_ == __y.__mean_;}
4527        friend _LIBCPP_INLINE_VISIBILITY
4528            bool operator!=(const param_type& __x, const param_type& __y)
4529            {return !(__x == __y);}
4530
4531        friend class poisson_distribution;
4532    };
4533
4534private:
4535    param_type __p_;
4536
4537public:
4538    // constructors and reset functions
4539    _LIBCPP_INLINE_VISIBILITY
4540    explicit poisson_distribution(double __mean = 1.0) : __p_(__mean) {}
4541    _LIBCPP_INLINE_VISIBILITY
4542    explicit poisson_distribution(const param_type& __p) : __p_(__p) {}
4543    _LIBCPP_INLINE_VISIBILITY
4544    void reset() {}
4545
4546    // generating functions
4547    template<class _URNG>
4548        _LIBCPP_INLINE_VISIBILITY
4549        result_type operator()(_URNG& __g)
4550        {return (*this)(__g, __p_);}
4551    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4552
4553    // property functions
4554    _LIBCPP_INLINE_VISIBILITY
4555    double mean() const {return __p_.mean();}
4556
4557    _LIBCPP_INLINE_VISIBILITY
4558    param_type param() const {return __p_;}
4559    _LIBCPP_INLINE_VISIBILITY
4560    void param(const param_type& __p) {__p_ = __p;}
4561
4562    _LIBCPP_INLINE_VISIBILITY
4563    result_type min() const {return 0;}
4564    _LIBCPP_INLINE_VISIBILITY
4565    result_type max() const {return numeric_limits<result_type>::max();}
4566
4567    friend _LIBCPP_INLINE_VISIBILITY
4568        bool operator==(const poisson_distribution& __x,
4569                        const poisson_distribution& __y)
4570        {return __x.__p_ == __y.__p_;}
4571    friend _LIBCPP_INLINE_VISIBILITY
4572        bool operator!=(const poisson_distribution& __x,
4573                        const poisson_distribution& __y)
4574        {return !(__x == __y);}
4575};
4576
4577template<class _IntType>
4578poisson_distribution<_IntType>::param_type::param_type(double __mean)
4579    // According to the standard `inf` is a valid input, but it causes the
4580    // distribution to hang, so we replace it with the maximum representable
4581    // mean.
4582    : __mean_(isinf(__mean) ? numeric_limits<double>::max() : __mean)
4583{
4584    if (__mean_ < 10)
4585    {
4586        __s_ = 0;
4587        __d_ = 0;
4588        __l_ = _VSTD::exp(-__mean_);
4589        __omega_ = 0;
4590        __c3_ = 0;
4591        __c2_ = 0;
4592        __c1_ = 0;
4593        __c0_ = 0;
4594        __c_ = 0;
4595    }
4596    else
4597    {
4598        __s_ = _VSTD::sqrt(__mean_);
4599        __d_ = 6 * __mean_ * __mean_;
4600        __l_ = std::trunc(__mean_ - 1.1484);
4601        __omega_ = .3989423 / __s_;
4602        double __b1_ = .4166667E-1 / __mean_;
4603        double __b2_ = .3 * __b1_ * __b1_;
4604        __c3_ = .1428571 * __b1_ * __b2_;
4605        __c2_ = __b2_ - 15. * __c3_;
4606        __c1_ = __b1_ - 6. * __b2_ + 45. * __c3_;
4607        __c0_ = 1. - __b1_ + 3. * __b2_ - 15. * __c3_;
4608        __c_ = .1069 / __mean_;
4609    }
4610}
4611
4612template <class _IntType>
4613template<class _URNG>
4614_IntType
4615poisson_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
4616{
4617    double __tx;
4618    uniform_real_distribution<double> __urd;
4619    if (__pr.__mean_ < 10)
4620    {
4621         __tx = 0;
4622        for (double __p = __urd(__urng); __p > __pr.__l_; ++__tx)
4623            __p *= __urd(__urng);
4624    }
4625    else
4626    {
4627        double __difmuk;
4628        double __g = __pr.__mean_ + __pr.__s_ * normal_distribution<double>()(__urng);
4629        double __u;
4630        if (__g > 0)
4631        {
4632            __tx = std::trunc(__g);
4633            if (__tx >= __pr.__l_)
4634                return std::__clamp_to_integral<result_type>(__tx);
4635            __difmuk = __pr.__mean_ - __tx;
4636            __u = __urd(__urng);
4637            if (__pr.__d_ * __u >= __difmuk * __difmuk * __difmuk)
4638                return std::__clamp_to_integral<result_type>(__tx);
4639        }
4640        exponential_distribution<double> __edist;
4641        for (bool __using_exp_dist = false; true; __using_exp_dist = true)
4642        {
4643            double __e;
4644            if (__using_exp_dist || __g <= 0)
4645            {
4646                double __t;
4647                do
4648                {
4649                    __e = __edist(__urng);
4650                    __u = __urd(__urng);
4651                    __u += __u - 1;
4652                    __t = 1.8 + (__u < 0 ? -__e : __e);
4653                } while (__t <= -.6744);
4654                __tx = std::trunc(__pr.__mean_ + __pr.__s_ * __t);
4655                __difmuk = __pr.__mean_ - __tx;
4656                __using_exp_dist = true;
4657            }
4658            double __px;
4659            double __py;
4660            if (__tx < 10 && __tx >= 0)
4661            {
4662                const result_type __fac[] = {1, 1, 2, 6, 24, 120, 720, 5040,
4663                                             40320, 362880};
4664                __px = -__pr.__mean_;
4665                __py = _VSTD::pow(__pr.__mean_, (double)__tx) / __fac[static_cast<int>(__tx)];
4666            }
4667            else
4668            {
4669                double __del = .8333333E-1 / __tx;
4670                __del -= 4.8 * __del * __del * __del;
4671                double __v = __difmuk / __tx;
4672                if (_VSTD::abs(__v) > 0.25)
4673                    __px = __tx * _VSTD::log(1 + __v) - __difmuk - __del;
4674                else
4675                    __px = __tx * __v * __v * (((((((.1250060 * __v + -.1384794) *
4676                           __v + .1421878) * __v + -.1661269) * __v + .2000118) *
4677                           __v + -.2500068) * __v + .3333333) * __v + -.5) - __del;
4678                __py = .3989423 / _VSTD::sqrt(__tx);
4679            }
4680            double __r = (0.5 - __difmuk) / __pr.__s_;
4681            double __r2 = __r * __r;
4682            double __fx = -0.5 * __r2;
4683            double __fy = __pr.__omega_ * (((__pr.__c3_ * __r2 + __pr.__c2_) *
4684                                        __r2 + __pr.__c1_) * __r2 + __pr.__c0_);
4685            if (__using_exp_dist)
4686            {
4687                if (__pr.__c_ * _VSTD::abs(__u) <= __py * _VSTD::exp(__px + __e) -
4688                                                   __fy * _VSTD::exp(__fx + __e))
4689                    break;
4690            }
4691            else
4692            {
4693                if (__fy - __u * __fy <= __py * _VSTD::exp(__px - __fx))
4694                    break;
4695            }
4696        }
4697    }
4698    return std::__clamp_to_integral<result_type>(__tx);
4699}
4700
4701template <class _CharT, class _Traits, class _IntType>
4702basic_ostream<_CharT, _Traits>&
4703operator<<(basic_ostream<_CharT, _Traits>& __os,
4704           const poisson_distribution<_IntType>& __x)
4705{
4706    __save_flags<_CharT, _Traits> __lx(__os);
4707    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4708               ios_base::scientific);
4709    return __os << __x.mean();
4710}
4711
4712template <class _CharT, class _Traits, class _IntType>
4713basic_istream<_CharT, _Traits>&
4714operator>>(basic_istream<_CharT, _Traits>& __is,
4715           poisson_distribution<_IntType>& __x)
4716{
4717    typedef poisson_distribution<_IntType> _Eng;
4718    typedef typename _Eng::param_type param_type;
4719    __save_flags<_CharT, _Traits> __lx(__is);
4720    __is.flags(ios_base::dec | ios_base::skipws);
4721    double __mean;
4722    __is >> __mean;
4723    if (!__is.fail())
4724        __x.param(param_type(__mean));
4725    return __is;
4726}
4727
4728// weibull_distribution
4729
4730template<class _RealType = double>
4731class _LIBCPP_TEMPLATE_VIS weibull_distribution
4732{
4733public:
4734    // types
4735    typedef _RealType result_type;
4736
4737    class _LIBCPP_TEMPLATE_VIS param_type
4738    {
4739        result_type __a_;
4740        result_type __b_;
4741    public:
4742        typedef weibull_distribution distribution_type;
4743
4744        _LIBCPP_INLINE_VISIBILITY
4745        explicit param_type(result_type __a = 1, result_type __b = 1)
4746            : __a_(__a), __b_(__b) {}
4747
4748        _LIBCPP_INLINE_VISIBILITY
4749        result_type a() const {return __a_;}
4750        _LIBCPP_INLINE_VISIBILITY
4751        result_type b() const {return __b_;}
4752
4753        friend _LIBCPP_INLINE_VISIBILITY
4754            bool operator==(const param_type& __x, const param_type& __y)
4755            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
4756        friend _LIBCPP_INLINE_VISIBILITY
4757            bool operator!=(const param_type& __x, const param_type& __y)
4758            {return !(__x == __y);}
4759    };
4760
4761private:
4762    param_type __p_;
4763
4764public:
4765    // constructor and reset functions
4766    _LIBCPP_INLINE_VISIBILITY
4767    explicit weibull_distribution(result_type __a = 1, result_type __b = 1)
4768        : __p_(param_type(__a, __b)) {}
4769    _LIBCPP_INLINE_VISIBILITY
4770    explicit weibull_distribution(const param_type& __p)
4771        : __p_(__p) {}
4772    _LIBCPP_INLINE_VISIBILITY
4773    void reset() {}
4774
4775    // generating functions
4776    template<class _URNG>
4777        _LIBCPP_INLINE_VISIBILITY
4778        result_type operator()(_URNG& __g)
4779        {return (*this)(__g, __p_);}
4780    template<class _URNG>
4781        _LIBCPP_INLINE_VISIBILITY
4782        result_type operator()(_URNG& __g, const param_type& __p)
4783        {return __p.b() *
4784            _VSTD::pow(exponential_distribution<result_type>()(__g), 1/__p.a());}
4785
4786    // property functions
4787    _LIBCPP_INLINE_VISIBILITY
4788    result_type a() const {return __p_.a();}
4789    _LIBCPP_INLINE_VISIBILITY
4790    result_type b() const {return __p_.b();}
4791
4792    _LIBCPP_INLINE_VISIBILITY
4793    param_type param() const {return __p_;}
4794    _LIBCPP_INLINE_VISIBILITY
4795    void param(const param_type& __p) {__p_ = __p;}
4796
4797    _LIBCPP_INLINE_VISIBILITY
4798    result_type min() const {return 0;}
4799    _LIBCPP_INLINE_VISIBILITY
4800    result_type max() const {return numeric_limits<result_type>::infinity();}
4801
4802    friend _LIBCPP_INLINE_VISIBILITY
4803        bool operator==(const weibull_distribution& __x,
4804                        const weibull_distribution& __y)
4805        {return __x.__p_ == __y.__p_;}
4806    friend _LIBCPP_INLINE_VISIBILITY
4807        bool operator!=(const weibull_distribution& __x,
4808                        const weibull_distribution& __y)
4809        {return !(__x == __y);}
4810};
4811
4812template <class _CharT, class _Traits, class _RT>
4813basic_ostream<_CharT, _Traits>&
4814operator<<(basic_ostream<_CharT, _Traits>& __os,
4815           const weibull_distribution<_RT>& __x)
4816{
4817    __save_flags<_CharT, _Traits> __lx(__os);
4818    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4819               ios_base::scientific);
4820    _CharT __sp = __os.widen(' ');
4821    __os.fill(__sp);
4822    __os << __x.a() << __sp << __x.b();
4823    return __os;
4824}
4825
4826template <class _CharT, class _Traits, class _RT>
4827basic_istream<_CharT, _Traits>&
4828operator>>(basic_istream<_CharT, _Traits>& __is,
4829           weibull_distribution<_RT>& __x)
4830{
4831    typedef weibull_distribution<_RT> _Eng;
4832    typedef typename _Eng::result_type result_type;
4833    typedef typename _Eng::param_type param_type;
4834    __save_flags<_CharT, _Traits> __lx(__is);
4835    __is.flags(ios_base::dec | ios_base::skipws);
4836    result_type __a;
4837    result_type __b;
4838    __is >> __a >> __b;
4839    if (!__is.fail())
4840        __x.param(param_type(__a, __b));
4841    return __is;
4842}
4843
4844template<class _RealType = double>
4845class _LIBCPP_TEMPLATE_VIS extreme_value_distribution
4846{
4847public:
4848    // types
4849    typedef _RealType result_type;
4850
4851    class _LIBCPP_TEMPLATE_VIS param_type
4852    {
4853        result_type __a_;
4854        result_type __b_;
4855    public:
4856        typedef extreme_value_distribution distribution_type;
4857
4858        _LIBCPP_INLINE_VISIBILITY
4859        explicit param_type(result_type __a = 0, result_type __b = 1)
4860            : __a_(__a), __b_(__b) {}
4861
4862        _LIBCPP_INLINE_VISIBILITY
4863        result_type a() const {return __a_;}
4864        _LIBCPP_INLINE_VISIBILITY
4865        result_type b() const {return __b_;}
4866
4867        friend _LIBCPP_INLINE_VISIBILITY
4868            bool operator==(const param_type& __x, const param_type& __y)
4869            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
4870        friend _LIBCPP_INLINE_VISIBILITY
4871            bool operator!=(const param_type& __x, const param_type& __y)
4872            {return !(__x == __y);}
4873    };
4874
4875private:
4876    param_type __p_;
4877
4878public:
4879    // constructor and reset functions
4880    _LIBCPP_INLINE_VISIBILITY
4881    explicit extreme_value_distribution(result_type __a = 0, result_type __b = 1)
4882        : __p_(param_type(__a, __b)) {}
4883    _LIBCPP_INLINE_VISIBILITY
4884    explicit extreme_value_distribution(const param_type& __p)
4885        : __p_(__p) {}
4886    _LIBCPP_INLINE_VISIBILITY
4887    void reset() {}
4888
4889    // generating functions
4890    template<class _URNG>
4891        _LIBCPP_INLINE_VISIBILITY
4892        result_type operator()(_URNG& __g)
4893        {return (*this)(__g, __p_);}
4894    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4895
4896    // property functions
4897    _LIBCPP_INLINE_VISIBILITY
4898    result_type a() const {return __p_.a();}
4899    _LIBCPP_INLINE_VISIBILITY
4900    result_type b() const {return __p_.b();}
4901
4902    _LIBCPP_INLINE_VISIBILITY
4903    param_type param() const {return __p_;}
4904    _LIBCPP_INLINE_VISIBILITY
4905    void param(const param_type& __p) {__p_ = __p;}
4906
4907    _LIBCPP_INLINE_VISIBILITY
4908    result_type min() const {return -numeric_limits<result_type>::infinity();}
4909    _LIBCPP_INLINE_VISIBILITY
4910    result_type max() const {return numeric_limits<result_type>::infinity();}
4911
4912    friend _LIBCPP_INLINE_VISIBILITY
4913        bool operator==(const extreme_value_distribution& __x,
4914                        const extreme_value_distribution& __y)
4915        {return __x.__p_ == __y.__p_;}
4916    friend _LIBCPP_INLINE_VISIBILITY
4917        bool operator!=(const extreme_value_distribution& __x,
4918                        const extreme_value_distribution& __y)
4919        {return !(__x == __y);}
4920};
4921
4922template<class _RealType>
4923template<class _URNG>
4924_RealType
4925extreme_value_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4926{
4927    return __p.a() - __p.b() *
4928         _VSTD::log(-_VSTD::log(1-uniform_real_distribution<result_type>()(__g)));
4929}
4930
4931template <class _CharT, class _Traits, class _RT>
4932basic_ostream<_CharT, _Traits>&
4933operator<<(basic_ostream<_CharT, _Traits>& __os,
4934           const extreme_value_distribution<_RT>& __x)
4935{
4936    __save_flags<_CharT, _Traits> __lx(__os);
4937    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4938               ios_base::scientific);
4939    _CharT __sp = __os.widen(' ');
4940    __os.fill(__sp);
4941    __os << __x.a() << __sp << __x.b();
4942    return __os;
4943}
4944
4945template <class _CharT, class _Traits, class _RT>
4946basic_istream<_CharT, _Traits>&
4947operator>>(basic_istream<_CharT, _Traits>& __is,
4948           extreme_value_distribution<_RT>& __x)
4949{
4950    typedef extreme_value_distribution<_RT> _Eng;
4951    typedef typename _Eng::result_type result_type;
4952    typedef typename _Eng::param_type param_type;
4953    __save_flags<_CharT, _Traits> __lx(__is);
4954    __is.flags(ios_base::dec | ios_base::skipws);
4955    result_type __a;
4956    result_type __b;
4957    __is >> __a >> __b;
4958    if (!__is.fail())
4959        __x.param(param_type(__a, __b));
4960    return __is;
4961}
4962
4963// gamma_distribution
4964
4965template<class _RealType = double>
4966class _LIBCPP_TEMPLATE_VIS gamma_distribution
4967{
4968public:
4969    // types
4970    typedef _RealType result_type;
4971
4972    class _LIBCPP_TEMPLATE_VIS param_type
4973    {
4974        result_type __alpha_;
4975        result_type __beta_;
4976    public:
4977        typedef gamma_distribution distribution_type;
4978
4979        _LIBCPP_INLINE_VISIBILITY
4980        explicit param_type(result_type __alpha = 1, result_type __beta = 1)
4981            : __alpha_(__alpha), __beta_(__beta) {}
4982
4983        _LIBCPP_INLINE_VISIBILITY
4984        result_type alpha() const {return __alpha_;}
4985        _LIBCPP_INLINE_VISIBILITY
4986        result_type beta() const {return __beta_;}
4987
4988        friend _LIBCPP_INLINE_VISIBILITY
4989            bool operator==(const param_type& __x, const param_type& __y)
4990            {return __x.__alpha_ == __y.__alpha_ && __x.__beta_ == __y.__beta_;}
4991        friend _LIBCPP_INLINE_VISIBILITY
4992            bool operator!=(const param_type& __x, const param_type& __y)
4993            {return !(__x == __y);}
4994    };
4995
4996private:
4997    param_type __p_;
4998
4999public:
5000    // constructors and reset functions
5001    _LIBCPP_INLINE_VISIBILITY
5002    explicit gamma_distribution(result_type __alpha = 1, result_type __beta = 1)
5003        : __p_(param_type(__alpha, __beta)) {}
5004    _LIBCPP_INLINE_VISIBILITY
5005    explicit gamma_distribution(const param_type& __p)
5006        : __p_(__p) {}
5007    _LIBCPP_INLINE_VISIBILITY
5008    void reset() {}
5009
5010    // generating functions
5011    template<class _URNG>
5012        _LIBCPP_INLINE_VISIBILITY
5013        result_type operator()(_URNG& __g)
5014        {return (*this)(__g, __p_);}
5015    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5016
5017    // property functions
5018    _LIBCPP_INLINE_VISIBILITY
5019    result_type alpha() const {return __p_.alpha();}
5020    _LIBCPP_INLINE_VISIBILITY
5021    result_type beta() const {return __p_.beta();}
5022
5023    _LIBCPP_INLINE_VISIBILITY
5024    param_type param() const {return __p_;}
5025    _LIBCPP_INLINE_VISIBILITY
5026    void param(const param_type& __p) {__p_ = __p;}
5027
5028    _LIBCPP_INLINE_VISIBILITY
5029    result_type min() const {return 0;}
5030    _LIBCPP_INLINE_VISIBILITY
5031    result_type max() const {return numeric_limits<result_type>::infinity();}
5032
5033    friend _LIBCPP_INLINE_VISIBILITY
5034        bool operator==(const gamma_distribution& __x,
5035                        const gamma_distribution& __y)
5036        {return __x.__p_ == __y.__p_;}
5037    friend _LIBCPP_INLINE_VISIBILITY
5038        bool operator!=(const gamma_distribution& __x,
5039                        const gamma_distribution& __y)
5040        {return !(__x == __y);}
5041};
5042
5043template <class _RealType>
5044template<class _URNG>
5045_RealType
5046gamma_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5047{
5048    result_type __a = __p.alpha();
5049    uniform_real_distribution<result_type> __gen(0, 1);
5050    exponential_distribution<result_type> __egen;
5051    result_type __x;
5052    if (__a == 1)
5053        __x = __egen(__g);
5054    else if (__a > 1)
5055    {
5056        const result_type __b = __a - 1;
5057        const result_type __c = 3 * __a - result_type(0.75);
5058        while (true)
5059        {
5060            const result_type __u = __gen(__g);
5061            const result_type __v = __gen(__g);
5062            const result_type __w = __u * (1 - __u);
5063            if (__w != 0)
5064            {
5065                const result_type __y = _VSTD::sqrt(__c / __w) *
5066                                        (__u - result_type(0.5));
5067                __x = __b + __y;
5068                if (__x >= 0)
5069                {
5070                    const result_type __z = 64 * __w * __w * __w * __v * __v;
5071                    if (__z <= 1 - 2 * __y * __y / __x)
5072                        break;
5073                    if (_VSTD::log(__z) <= 2 * (__b * _VSTD::log(__x / __b) - __y))
5074                        break;
5075                }
5076            }
5077        }
5078    }
5079    else  // __a < 1
5080    {
5081        while (true)
5082        {
5083            const result_type __u = __gen(__g);
5084            const result_type __es = __egen(__g);
5085            if (__u <= 1 - __a)
5086            {
5087                __x = _VSTD::pow(__u, 1 / __a);
5088                if (__x <= __es)
5089                    break;
5090            }
5091            else
5092            {
5093                const result_type __e = -_VSTD::log((1-__u)/__a);
5094                __x = _VSTD::pow(1 - __a + __a * __e, 1 / __a);
5095                if (__x <= __e + __es)
5096                    break;
5097            }
5098        }
5099    }
5100    return __x * __p.beta();
5101}
5102
5103template <class _CharT, class _Traits, class _RT>
5104basic_ostream<_CharT, _Traits>&
5105operator<<(basic_ostream<_CharT, _Traits>& __os,
5106           const gamma_distribution<_RT>& __x)
5107{
5108    __save_flags<_CharT, _Traits> __lx(__os);
5109    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5110               ios_base::scientific);
5111    _CharT __sp = __os.widen(' ');
5112    __os.fill(__sp);
5113    __os << __x.alpha() << __sp << __x.beta();
5114    return __os;
5115}
5116
5117template <class _CharT, class _Traits, class _RT>
5118basic_istream<_CharT, _Traits>&
5119operator>>(basic_istream<_CharT, _Traits>& __is,
5120           gamma_distribution<_RT>& __x)
5121{
5122    typedef gamma_distribution<_RT> _Eng;
5123    typedef typename _Eng::result_type result_type;
5124    typedef typename _Eng::param_type param_type;
5125    __save_flags<_CharT, _Traits> __lx(__is);
5126    __is.flags(ios_base::dec | ios_base::skipws);
5127    result_type __alpha;
5128    result_type __beta;
5129    __is >> __alpha >> __beta;
5130    if (!__is.fail())
5131        __x.param(param_type(__alpha, __beta));
5132    return __is;
5133}
5134
5135// negative_binomial_distribution
5136
5137template<class _IntType = int>
5138class _LIBCPP_TEMPLATE_VIS negative_binomial_distribution
5139{
5140public:
5141    // types
5142    typedef _IntType result_type;
5143
5144    class _LIBCPP_TEMPLATE_VIS param_type
5145    {
5146        result_type __k_;
5147        double __p_;
5148    public:
5149        typedef negative_binomial_distribution distribution_type;
5150
5151        _LIBCPP_INLINE_VISIBILITY
5152        explicit param_type(result_type __k = 1, double __p = 0.5)
5153            : __k_(__k), __p_(__p) {}
5154
5155        _LIBCPP_INLINE_VISIBILITY
5156        result_type k() const {return __k_;}
5157        _LIBCPP_INLINE_VISIBILITY
5158        double p() const {return __p_;}
5159
5160        friend _LIBCPP_INLINE_VISIBILITY
5161            bool operator==(const param_type& __x, const param_type& __y)
5162            {return __x.__k_ == __y.__k_ && __x.__p_ == __y.__p_;}
5163        friend _LIBCPP_INLINE_VISIBILITY
5164            bool operator!=(const param_type& __x, const param_type& __y)
5165            {return !(__x == __y);}
5166    };
5167
5168private:
5169    param_type __p_;
5170
5171public:
5172    // constructor and reset functions
5173    _LIBCPP_INLINE_VISIBILITY
5174    explicit negative_binomial_distribution(result_type __k = 1, double __p = 0.5)
5175        : __p_(__k, __p) {}
5176    _LIBCPP_INLINE_VISIBILITY
5177    explicit negative_binomial_distribution(const param_type& __p) : __p_(__p) {}
5178    _LIBCPP_INLINE_VISIBILITY
5179    void reset() {}
5180
5181    // generating functions
5182    template<class _URNG>
5183        _LIBCPP_INLINE_VISIBILITY
5184        result_type operator()(_URNG& __g)
5185        {return (*this)(__g, __p_);}
5186    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5187
5188    // property functions
5189    _LIBCPP_INLINE_VISIBILITY
5190    result_type k() const {return __p_.k();}
5191    _LIBCPP_INLINE_VISIBILITY
5192    double p() const {return __p_.p();}
5193
5194    _LIBCPP_INLINE_VISIBILITY
5195    param_type param() const {return __p_;}
5196    _LIBCPP_INLINE_VISIBILITY
5197    void param(const param_type& __p) {__p_ = __p;}
5198
5199    _LIBCPP_INLINE_VISIBILITY
5200    result_type min() const {return 0;}
5201    _LIBCPP_INLINE_VISIBILITY
5202    result_type max() const {return numeric_limits<result_type>::max();}
5203
5204    friend _LIBCPP_INLINE_VISIBILITY
5205        bool operator==(const negative_binomial_distribution& __x,
5206                        const negative_binomial_distribution& __y)
5207        {return __x.__p_ == __y.__p_;}
5208    friend _LIBCPP_INLINE_VISIBILITY
5209        bool operator!=(const negative_binomial_distribution& __x,
5210                        const negative_binomial_distribution& __y)
5211        {return !(__x == __y);}
5212};
5213
5214template <class _IntType>
5215template<class _URNG>
5216_IntType
5217negative_binomial_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
5218{
5219    result_type __k = __pr.k();
5220    double __p = __pr.p();
5221    if (__k <= 21 * __p)
5222    {
5223        bernoulli_distribution __gen(__p);
5224        result_type __f = 0;
5225        result_type __s = 0;
5226        while (__s < __k)
5227        {
5228            if (__gen(__urng))
5229                ++__s;
5230            else
5231                ++__f;
5232        }
5233        return __f;
5234    }
5235    return poisson_distribution<result_type>(gamma_distribution<double>
5236                                            (__k, (1-__p)/__p)(__urng))(__urng);
5237}
5238
5239template <class _CharT, class _Traits, class _IntType>
5240basic_ostream<_CharT, _Traits>&
5241operator<<(basic_ostream<_CharT, _Traits>& __os,
5242           const negative_binomial_distribution<_IntType>& __x)
5243{
5244    __save_flags<_CharT, _Traits> __lx(__os);
5245    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5246               ios_base::scientific);
5247    _CharT __sp = __os.widen(' ');
5248    __os.fill(__sp);
5249    return __os << __x.k() << __sp << __x.p();
5250}
5251
5252template <class _CharT, class _Traits, class _IntType>
5253basic_istream<_CharT, _Traits>&
5254operator>>(basic_istream<_CharT, _Traits>& __is,
5255           negative_binomial_distribution<_IntType>& __x)
5256{
5257    typedef negative_binomial_distribution<_IntType> _Eng;
5258    typedef typename _Eng::result_type result_type;
5259    typedef typename _Eng::param_type param_type;
5260    __save_flags<_CharT, _Traits> __lx(__is);
5261    __is.flags(ios_base::dec | ios_base::skipws);
5262    result_type __k;
5263    double __p;
5264    __is >> __k >> __p;
5265    if (!__is.fail())
5266        __x.param(param_type(__k, __p));
5267    return __is;
5268}
5269
5270// geometric_distribution
5271
5272template<class _IntType = int>
5273class _LIBCPP_TEMPLATE_VIS geometric_distribution
5274{
5275public:
5276    // types
5277    typedef _IntType result_type;
5278
5279    class _LIBCPP_TEMPLATE_VIS param_type
5280    {
5281        double __p_;
5282    public:
5283        typedef geometric_distribution distribution_type;
5284
5285        _LIBCPP_INLINE_VISIBILITY
5286        explicit param_type(double __p = 0.5) : __p_(__p) {}
5287
5288        _LIBCPP_INLINE_VISIBILITY
5289        double p() const {return __p_;}
5290
5291        friend _LIBCPP_INLINE_VISIBILITY
5292            bool operator==(const param_type& __x, const param_type& __y)
5293            {return __x.__p_ == __y.__p_;}
5294        friend _LIBCPP_INLINE_VISIBILITY
5295            bool operator!=(const param_type& __x, const param_type& __y)
5296            {return !(__x == __y);}
5297    };
5298
5299private:
5300    param_type __p_;
5301
5302public:
5303    // constructors and reset functions
5304    _LIBCPP_INLINE_VISIBILITY
5305    explicit geometric_distribution(double __p = 0.5) : __p_(__p) {}
5306    _LIBCPP_INLINE_VISIBILITY
5307    explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
5308    _LIBCPP_INLINE_VISIBILITY
5309    void reset() {}
5310
5311    // generating functions
5312    template<class _URNG>
5313        _LIBCPP_INLINE_VISIBILITY
5314        result_type operator()(_URNG& __g)
5315        {return (*this)(__g, __p_);}
5316    template<class _URNG>
5317        _LIBCPP_INLINE_VISIBILITY
5318        result_type operator()(_URNG& __g, const param_type& __p)
5319        {return negative_binomial_distribution<result_type>(1, __p.p())(__g);}
5320
5321    // property functions
5322    _LIBCPP_INLINE_VISIBILITY
5323    double p() const {return __p_.p();}
5324
5325    _LIBCPP_INLINE_VISIBILITY
5326    param_type param() const {return __p_;}
5327    _LIBCPP_INLINE_VISIBILITY
5328    void param(const param_type& __p) {__p_ = __p;}
5329
5330    _LIBCPP_INLINE_VISIBILITY
5331    result_type min() const {return 0;}
5332    _LIBCPP_INLINE_VISIBILITY
5333    result_type max() const {return numeric_limits<result_type>::max();}
5334
5335    friend _LIBCPP_INLINE_VISIBILITY
5336        bool operator==(const geometric_distribution& __x,
5337                        const geometric_distribution& __y)
5338        {return __x.__p_ == __y.__p_;}
5339    friend _LIBCPP_INLINE_VISIBILITY
5340        bool operator!=(const geometric_distribution& __x,
5341                        const geometric_distribution& __y)
5342        {return !(__x == __y);}
5343};
5344
5345template <class _CharT, class _Traits, class _IntType>
5346basic_ostream<_CharT, _Traits>&
5347operator<<(basic_ostream<_CharT, _Traits>& __os,
5348           const geometric_distribution<_IntType>& __x)
5349{
5350    __save_flags<_CharT, _Traits> __lx(__os);
5351    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5352               ios_base::scientific);
5353    return __os << __x.p();
5354}
5355
5356template <class _CharT, class _Traits, class _IntType>
5357basic_istream<_CharT, _Traits>&
5358operator>>(basic_istream<_CharT, _Traits>& __is,
5359           geometric_distribution<_IntType>& __x)
5360{
5361    typedef geometric_distribution<_IntType> _Eng;
5362    typedef typename _Eng::param_type param_type;
5363    __save_flags<_CharT, _Traits> __lx(__is);
5364    __is.flags(ios_base::dec | ios_base::skipws);
5365    double __p;
5366    __is >> __p;
5367    if (!__is.fail())
5368        __x.param(param_type(__p));
5369    return __is;
5370}
5371
5372// chi_squared_distribution
5373
5374template<class _RealType = double>
5375class _LIBCPP_TEMPLATE_VIS chi_squared_distribution
5376{
5377public:
5378    // types
5379    typedef _RealType result_type;
5380
5381    class _LIBCPP_TEMPLATE_VIS param_type
5382    {
5383        result_type __n_;
5384    public:
5385        typedef chi_squared_distribution distribution_type;
5386
5387        _LIBCPP_INLINE_VISIBILITY
5388        explicit param_type(result_type __n = 1) : __n_(__n) {}
5389
5390        _LIBCPP_INLINE_VISIBILITY
5391        result_type n() const {return __n_;}
5392
5393        friend _LIBCPP_INLINE_VISIBILITY
5394            bool operator==(const param_type& __x, const param_type& __y)
5395            {return __x.__n_ == __y.__n_;}
5396        friend _LIBCPP_INLINE_VISIBILITY
5397            bool operator!=(const param_type& __x, const param_type& __y)
5398            {return !(__x == __y);}
5399    };
5400
5401private:
5402    param_type __p_;
5403
5404public:
5405    // constructor and reset functions
5406    _LIBCPP_INLINE_VISIBILITY
5407    explicit chi_squared_distribution(result_type __n = 1)
5408        : __p_(param_type(__n)) {}
5409    _LIBCPP_INLINE_VISIBILITY
5410    explicit chi_squared_distribution(const param_type& __p)
5411        : __p_(__p) {}
5412    _LIBCPP_INLINE_VISIBILITY
5413    void reset() {}
5414
5415    // generating functions
5416    template<class _URNG>
5417        _LIBCPP_INLINE_VISIBILITY
5418        result_type operator()(_URNG& __g)
5419        {return (*this)(__g, __p_);}
5420    template<class _URNG>
5421        _LIBCPP_INLINE_VISIBILITY
5422        result_type operator()(_URNG& __g, const param_type& __p)
5423        {return gamma_distribution<result_type>(__p.n() / 2, 2)(__g);}
5424
5425    // property functions
5426    _LIBCPP_INLINE_VISIBILITY
5427    result_type n() const {return __p_.n();}
5428
5429    _LIBCPP_INLINE_VISIBILITY
5430    param_type param() const {return __p_;}
5431    _LIBCPP_INLINE_VISIBILITY
5432    void param(const param_type& __p) {__p_ = __p;}
5433
5434    _LIBCPP_INLINE_VISIBILITY
5435    result_type min() const {return 0;}
5436    _LIBCPP_INLINE_VISIBILITY
5437    result_type max() const {return numeric_limits<result_type>::infinity();}
5438
5439    friend _LIBCPP_INLINE_VISIBILITY
5440        bool operator==(const chi_squared_distribution& __x,
5441                        const chi_squared_distribution& __y)
5442        {return __x.__p_ == __y.__p_;}
5443    friend _LIBCPP_INLINE_VISIBILITY
5444        bool operator!=(const chi_squared_distribution& __x,
5445                        const chi_squared_distribution& __y)
5446        {return !(__x == __y);}
5447};
5448
5449template <class _CharT, class _Traits, class _RT>
5450basic_ostream<_CharT, _Traits>&
5451operator<<(basic_ostream<_CharT, _Traits>& __os,
5452           const chi_squared_distribution<_RT>& __x)
5453{
5454    __save_flags<_CharT, _Traits> __lx(__os);
5455    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5456               ios_base::scientific);
5457    __os << __x.n();
5458    return __os;
5459}
5460
5461template <class _CharT, class _Traits, class _RT>
5462basic_istream<_CharT, _Traits>&
5463operator>>(basic_istream<_CharT, _Traits>& __is,
5464           chi_squared_distribution<_RT>& __x)
5465{
5466    typedef chi_squared_distribution<_RT> _Eng;
5467    typedef typename _Eng::result_type result_type;
5468    typedef typename _Eng::param_type param_type;
5469    __save_flags<_CharT, _Traits> __lx(__is);
5470    __is.flags(ios_base::dec | ios_base::skipws);
5471    result_type __n;
5472    __is >> __n;
5473    if (!__is.fail())
5474        __x.param(param_type(__n));
5475    return __is;
5476}
5477
5478// cauchy_distribution
5479
5480template<class _RealType = double>
5481class _LIBCPP_TEMPLATE_VIS cauchy_distribution
5482{
5483public:
5484    // types
5485    typedef _RealType result_type;
5486
5487    class _LIBCPP_TEMPLATE_VIS param_type
5488    {
5489        result_type __a_;
5490        result_type __b_;
5491    public:
5492        typedef cauchy_distribution distribution_type;
5493
5494        _LIBCPP_INLINE_VISIBILITY
5495        explicit param_type(result_type __a = 0, result_type __b = 1)
5496            : __a_(__a), __b_(__b) {}
5497
5498        _LIBCPP_INLINE_VISIBILITY
5499        result_type a() const {return __a_;}
5500        _LIBCPP_INLINE_VISIBILITY
5501        result_type b() const {return __b_;}
5502
5503        friend _LIBCPP_INLINE_VISIBILITY
5504            bool operator==(const param_type& __x, const param_type& __y)
5505            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
5506        friend _LIBCPP_INLINE_VISIBILITY
5507            bool operator!=(const param_type& __x, const param_type& __y)
5508            {return !(__x == __y);}
5509    };
5510
5511private:
5512    param_type __p_;
5513
5514public:
5515    // constructor and reset functions
5516    _LIBCPP_INLINE_VISIBILITY
5517    explicit cauchy_distribution(result_type __a = 0, result_type __b = 1)
5518        : __p_(param_type(__a, __b)) {}
5519    _LIBCPP_INLINE_VISIBILITY
5520    explicit cauchy_distribution(const param_type& __p)
5521        : __p_(__p) {}
5522    _LIBCPP_INLINE_VISIBILITY
5523    void reset() {}
5524
5525    // generating functions
5526    template<class _URNG>
5527        _LIBCPP_INLINE_VISIBILITY
5528        result_type operator()(_URNG& __g)
5529        {return (*this)(__g, __p_);}
5530    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
5531
5532    // property functions
5533    _LIBCPP_INLINE_VISIBILITY
5534    result_type a() const {return __p_.a();}
5535    _LIBCPP_INLINE_VISIBILITY
5536    result_type b() const {return __p_.b();}
5537
5538    _LIBCPP_INLINE_VISIBILITY
5539    param_type param() const {return __p_;}
5540    _LIBCPP_INLINE_VISIBILITY
5541    void param(const param_type& __p) {__p_ = __p;}
5542
5543    _LIBCPP_INLINE_VISIBILITY
5544    result_type min() const {return -numeric_limits<result_type>::infinity();}
5545    _LIBCPP_INLINE_VISIBILITY
5546    result_type max() const {return numeric_limits<result_type>::infinity();}
5547
5548    friend _LIBCPP_INLINE_VISIBILITY
5549        bool operator==(const cauchy_distribution& __x,
5550                        const cauchy_distribution& __y)
5551        {return __x.__p_ == __y.__p_;}
5552    friend _LIBCPP_INLINE_VISIBILITY
5553        bool operator!=(const cauchy_distribution& __x,
5554                        const cauchy_distribution& __y)
5555        {return !(__x == __y);}
5556};
5557
5558template <class _RealType>
5559template<class _URNG>
5560inline
5561_RealType
5562cauchy_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5563{
5564    uniform_real_distribution<result_type> __gen;
5565    // purposefully let tan arg get as close to pi/2 as it wants, tan will return a finite
5566    return __p.a() + __p.b() * _VSTD::tan(3.1415926535897932384626433832795 * __gen(__g));
5567}
5568
5569template <class _CharT, class _Traits, class _RT>
5570basic_ostream<_CharT, _Traits>&
5571operator<<(basic_ostream<_CharT, _Traits>& __os,
5572           const cauchy_distribution<_RT>& __x)
5573{
5574    __save_flags<_CharT, _Traits> __lx(__os);
5575    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5576               ios_base::scientific);
5577    _CharT __sp = __os.widen(' ');
5578    __os.fill(__sp);
5579    __os << __x.a() << __sp << __x.b();
5580    return __os;
5581}
5582
5583template <class _CharT, class _Traits, class _RT>
5584basic_istream<_CharT, _Traits>&
5585operator>>(basic_istream<_CharT, _Traits>& __is,
5586           cauchy_distribution<_RT>& __x)
5587{
5588    typedef cauchy_distribution<_RT> _Eng;
5589    typedef typename _Eng::result_type result_type;
5590    typedef typename _Eng::param_type param_type;
5591    __save_flags<_CharT, _Traits> __lx(__is);
5592    __is.flags(ios_base::dec | ios_base::skipws);
5593    result_type __a;
5594    result_type __b;
5595    __is >> __a >> __b;
5596    if (!__is.fail())
5597        __x.param(param_type(__a, __b));
5598    return __is;
5599}
5600
5601// fisher_f_distribution
5602
5603template<class _RealType = double>
5604class _LIBCPP_TEMPLATE_VIS fisher_f_distribution
5605{
5606public:
5607    // types
5608    typedef _RealType result_type;
5609
5610    class _LIBCPP_TEMPLATE_VIS param_type
5611    {
5612        result_type __m_;
5613        result_type __n_;
5614    public:
5615        typedef fisher_f_distribution distribution_type;
5616
5617        _LIBCPP_INLINE_VISIBILITY
5618        explicit param_type(result_type __m = 1, result_type __n = 1)
5619            : __m_(__m), __n_(__n) {}
5620
5621        _LIBCPP_INLINE_VISIBILITY
5622        result_type m() const {return __m_;}
5623        _LIBCPP_INLINE_VISIBILITY
5624        result_type n() const {return __n_;}
5625
5626        friend _LIBCPP_INLINE_VISIBILITY
5627            bool operator==(const param_type& __x, const param_type& __y)
5628            {return __x.__m_ == __y.__m_ && __x.__n_ == __y.__n_;}
5629        friend _LIBCPP_INLINE_VISIBILITY
5630            bool operator!=(const param_type& __x, const param_type& __y)
5631            {return !(__x == __y);}
5632    };
5633
5634private:
5635    param_type __p_;
5636
5637public:
5638    // constructor and reset functions
5639    _LIBCPP_INLINE_VISIBILITY
5640    explicit fisher_f_distribution(result_type __m = 1, result_type __n = 1)
5641        : __p_(param_type(__m, __n)) {}
5642    _LIBCPP_INLINE_VISIBILITY
5643    explicit fisher_f_distribution(const param_type& __p)
5644        : __p_(__p) {}
5645    _LIBCPP_INLINE_VISIBILITY
5646    void reset() {}
5647
5648    // generating functions
5649    template<class _URNG>
5650        _LIBCPP_INLINE_VISIBILITY
5651        result_type operator()(_URNG& __g)
5652        {return (*this)(__g, __p_);}
5653    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5654
5655    // property functions
5656    _LIBCPP_INLINE_VISIBILITY
5657    result_type m() const {return __p_.m();}
5658    _LIBCPP_INLINE_VISIBILITY
5659    result_type n() const {return __p_.n();}
5660
5661    _LIBCPP_INLINE_VISIBILITY
5662    param_type param() const {return __p_;}
5663    _LIBCPP_INLINE_VISIBILITY
5664    void param(const param_type& __p) {__p_ = __p;}
5665
5666    _LIBCPP_INLINE_VISIBILITY
5667    result_type min() const {return 0;}
5668    _LIBCPP_INLINE_VISIBILITY
5669    result_type max() const {return numeric_limits<result_type>::infinity();}
5670
5671    friend _LIBCPP_INLINE_VISIBILITY
5672        bool operator==(const fisher_f_distribution& __x,
5673                        const fisher_f_distribution& __y)
5674        {return __x.__p_ == __y.__p_;}
5675    friend _LIBCPP_INLINE_VISIBILITY
5676        bool operator!=(const fisher_f_distribution& __x,
5677                        const fisher_f_distribution& __y)
5678        {return !(__x == __y);}
5679};
5680
5681template <class _RealType>
5682template<class _URNG>
5683_RealType
5684fisher_f_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5685{
5686    gamma_distribution<result_type> __gdm(__p.m() * result_type(.5));
5687    gamma_distribution<result_type> __gdn(__p.n() * result_type(.5));
5688    return __p.n() * __gdm(__g) / (__p.m() * __gdn(__g));
5689}
5690
5691template <class _CharT, class _Traits, class _RT>
5692basic_ostream<_CharT, _Traits>&
5693operator<<(basic_ostream<_CharT, _Traits>& __os,
5694           const fisher_f_distribution<_RT>& __x)
5695{
5696    __save_flags<_CharT, _Traits> __lx(__os);
5697    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5698               ios_base::scientific);
5699    _CharT __sp = __os.widen(' ');
5700    __os.fill(__sp);
5701    __os << __x.m() << __sp << __x.n();
5702    return __os;
5703}
5704
5705template <class _CharT, class _Traits, class _RT>
5706basic_istream<_CharT, _Traits>&
5707operator>>(basic_istream<_CharT, _Traits>& __is,
5708           fisher_f_distribution<_RT>& __x)
5709{
5710    typedef fisher_f_distribution<_RT> _Eng;
5711    typedef typename _Eng::result_type result_type;
5712    typedef typename _Eng::param_type param_type;
5713    __save_flags<_CharT, _Traits> __lx(__is);
5714    __is.flags(ios_base::dec | ios_base::skipws);
5715    result_type __m;
5716    result_type __n;
5717    __is >> __m >> __n;
5718    if (!__is.fail())
5719        __x.param(param_type(__m, __n));
5720    return __is;
5721}
5722
5723// student_t_distribution
5724
5725template<class _RealType = double>
5726class _LIBCPP_TEMPLATE_VIS student_t_distribution
5727{
5728public:
5729    // types
5730    typedef _RealType result_type;
5731
5732    class _LIBCPP_TEMPLATE_VIS param_type
5733    {
5734        result_type __n_;
5735    public:
5736        typedef student_t_distribution distribution_type;
5737
5738        _LIBCPP_INLINE_VISIBILITY
5739        explicit param_type(result_type __n = 1) : __n_(__n) {}
5740
5741        _LIBCPP_INLINE_VISIBILITY
5742        result_type n() const {return __n_;}
5743
5744        friend _LIBCPP_INLINE_VISIBILITY
5745            bool operator==(const param_type& __x, const param_type& __y)
5746            {return __x.__n_ == __y.__n_;}
5747        friend _LIBCPP_INLINE_VISIBILITY
5748            bool operator!=(const param_type& __x, const param_type& __y)
5749            {return !(__x == __y);}
5750    };
5751
5752private:
5753    param_type __p_;
5754    normal_distribution<result_type> __nd_;
5755
5756public:
5757    // constructor and reset functions
5758    _LIBCPP_INLINE_VISIBILITY
5759    explicit student_t_distribution(result_type __n = 1)
5760        : __p_(param_type(__n)) {}
5761    _LIBCPP_INLINE_VISIBILITY
5762    explicit student_t_distribution(const param_type& __p)
5763        : __p_(__p) {}
5764    _LIBCPP_INLINE_VISIBILITY
5765    void reset() {__nd_.reset();}
5766
5767    // generating functions
5768    template<class _URNG>
5769        _LIBCPP_INLINE_VISIBILITY
5770        result_type operator()(_URNG& __g)
5771        {return (*this)(__g, __p_);}
5772    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5773
5774    // property functions
5775    _LIBCPP_INLINE_VISIBILITY
5776    result_type n() const {return __p_.n();}
5777
5778    _LIBCPP_INLINE_VISIBILITY
5779    param_type param() const {return __p_;}
5780    _LIBCPP_INLINE_VISIBILITY
5781    void param(const param_type& __p) {__p_ = __p;}
5782
5783    _LIBCPP_INLINE_VISIBILITY
5784    result_type min() const {return -numeric_limits<result_type>::infinity();}
5785    _LIBCPP_INLINE_VISIBILITY
5786    result_type max() const {return numeric_limits<result_type>::infinity();}
5787
5788    friend _LIBCPP_INLINE_VISIBILITY
5789        bool operator==(const student_t_distribution& __x,
5790                        const student_t_distribution& __y)
5791        {return __x.__p_ == __y.__p_;}
5792    friend _LIBCPP_INLINE_VISIBILITY
5793        bool operator!=(const student_t_distribution& __x,
5794                        const student_t_distribution& __y)
5795        {return !(__x == __y);}
5796};
5797
5798template <class _RealType>
5799template<class _URNG>
5800_RealType
5801student_t_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5802{
5803    gamma_distribution<result_type> __gd(__p.n() * .5, 2);
5804    return __nd_(__g) * _VSTD::sqrt(__p.n()/__gd(__g));
5805}
5806
5807template <class _CharT, class _Traits, class _RT>
5808basic_ostream<_CharT, _Traits>&
5809operator<<(basic_ostream<_CharT, _Traits>& __os,
5810           const student_t_distribution<_RT>& __x)
5811{
5812    __save_flags<_CharT, _Traits> __lx(__os);
5813    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5814               ios_base::scientific);
5815    __os << __x.n();
5816    return __os;
5817}
5818
5819template <class _CharT, class _Traits, class _RT>
5820basic_istream<_CharT, _Traits>&
5821operator>>(basic_istream<_CharT, _Traits>& __is,
5822           student_t_distribution<_RT>& __x)
5823{
5824    typedef student_t_distribution<_RT> _Eng;
5825    typedef typename _Eng::result_type result_type;
5826    typedef typename _Eng::param_type param_type;
5827    __save_flags<_CharT, _Traits> __lx(__is);
5828    __is.flags(ios_base::dec | ios_base::skipws);
5829    result_type __n;
5830    __is >> __n;
5831    if (!__is.fail())
5832        __x.param(param_type(__n));
5833    return __is;
5834}
5835
5836// discrete_distribution
5837
5838template<class _IntType = int>
5839class _LIBCPP_TEMPLATE_VIS discrete_distribution
5840{
5841public:
5842    // types
5843    typedef _IntType result_type;
5844
5845    class _LIBCPP_TEMPLATE_VIS param_type
5846    {
5847        vector<double> __p_;
5848    public:
5849        typedef discrete_distribution distribution_type;
5850
5851        _LIBCPP_INLINE_VISIBILITY
5852        param_type() {}
5853        template<class _InputIterator>
5854            _LIBCPP_INLINE_VISIBILITY
5855            param_type(_InputIterator __f, _InputIterator __l)
5856            : __p_(__f, __l) {__init();}
5857#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5858        _LIBCPP_INLINE_VISIBILITY
5859        param_type(initializer_list<double> __wl)
5860            : __p_(__wl.begin(), __wl.end()) {__init();}
5861#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5862        template<class _UnaryOperation>
5863            param_type(size_t __nw, double __xmin, double __xmax,
5864                       _UnaryOperation __fw);
5865
5866        vector<double> probabilities() const;
5867
5868        friend _LIBCPP_INLINE_VISIBILITY
5869            bool operator==(const param_type& __x, const param_type& __y)
5870            {return __x.__p_ == __y.__p_;}
5871        friend _LIBCPP_INLINE_VISIBILITY
5872            bool operator!=(const param_type& __x, const param_type& __y)
5873            {return !(__x == __y);}
5874
5875    private:
5876        void __init();
5877
5878        friend class discrete_distribution;
5879
5880        template <class _CharT, class _Traits, class _IT>
5881        friend
5882        basic_ostream<_CharT, _Traits>&
5883        operator<<(basic_ostream<_CharT, _Traits>& __os,
5884                   const discrete_distribution<_IT>& __x);
5885
5886        template <class _CharT, class _Traits, class _IT>
5887        friend
5888        basic_istream<_CharT, _Traits>&
5889        operator>>(basic_istream<_CharT, _Traits>& __is,
5890                   discrete_distribution<_IT>& __x);
5891    };
5892
5893private:
5894    param_type __p_;
5895
5896public:
5897    // constructor and reset functions
5898    _LIBCPP_INLINE_VISIBILITY
5899    discrete_distribution() {}
5900    template<class _InputIterator>
5901        _LIBCPP_INLINE_VISIBILITY
5902        discrete_distribution(_InputIterator __f, _InputIterator __l)
5903            : __p_(__f, __l) {}
5904#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5905    _LIBCPP_INLINE_VISIBILITY
5906    discrete_distribution(initializer_list<double> __wl)
5907        : __p_(__wl) {}
5908#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
5909    template<class _UnaryOperation>
5910        _LIBCPP_INLINE_VISIBILITY
5911        discrete_distribution(size_t __nw, double __xmin, double __xmax,
5912                              _UnaryOperation __fw)
5913        : __p_(__nw, __xmin, __xmax, __fw) {}
5914    _LIBCPP_INLINE_VISIBILITY
5915    explicit discrete_distribution(const param_type& __p)
5916        : __p_(__p) {}
5917    _LIBCPP_INLINE_VISIBILITY
5918    void reset() {}
5919
5920    // generating functions
5921    template<class _URNG>
5922        _LIBCPP_INLINE_VISIBILITY
5923        result_type operator()(_URNG& __g)
5924        {return (*this)(__g, __p_);}
5925    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5926
5927    // property functions
5928    _LIBCPP_INLINE_VISIBILITY
5929    vector<double> probabilities() const {return __p_.probabilities();}
5930
5931    _LIBCPP_INLINE_VISIBILITY
5932    param_type param() const {return __p_;}
5933    _LIBCPP_INLINE_VISIBILITY
5934    void param(const param_type& __p) {__p_ = __p;}
5935
5936    _LIBCPP_INLINE_VISIBILITY
5937    result_type min() const {return 0;}
5938    _LIBCPP_INLINE_VISIBILITY
5939    result_type max() const {return __p_.__p_.size();}
5940
5941    friend _LIBCPP_INLINE_VISIBILITY
5942        bool operator==(const discrete_distribution& __x,
5943                        const discrete_distribution& __y)
5944        {return __x.__p_ == __y.__p_;}
5945    friend _LIBCPP_INLINE_VISIBILITY
5946        bool operator!=(const discrete_distribution& __x,
5947                        const discrete_distribution& __y)
5948        {return !(__x == __y);}
5949
5950    template <class _CharT, class _Traits, class _IT>
5951    friend
5952    basic_ostream<_CharT, _Traits>&
5953    operator<<(basic_ostream<_CharT, _Traits>& __os,
5954               const discrete_distribution<_IT>& __x);
5955
5956    template <class _CharT, class _Traits, class _IT>
5957    friend
5958    basic_istream<_CharT, _Traits>&
5959    operator>>(basic_istream<_CharT, _Traits>& __is,
5960               discrete_distribution<_IT>& __x);
5961};
5962
5963template<class _IntType>
5964template<class _UnaryOperation>
5965discrete_distribution<_IntType>::param_type::param_type(size_t __nw,
5966                                                        double __xmin,
5967                                                        double __xmax,
5968                                                        _UnaryOperation __fw)
5969{
5970    if (__nw > 1)
5971    {
5972        __p_.reserve(__nw - 1);
5973        double __d = (__xmax - __xmin) / __nw;
5974        double __d2 = __d / 2;
5975        for (size_t __k = 0; __k < __nw; ++__k)
5976            __p_.push_back(__fw(__xmin + __k * __d + __d2));
5977        __init();
5978    }
5979}
5980
5981template<class _IntType>
5982void
5983discrete_distribution<_IntType>::param_type::__init()
5984{
5985    if (!__p_.empty())
5986    {
5987        if (__p_.size() > 1)
5988        {
5989            double __s = _VSTD::accumulate(__p_.begin(), __p_.end(), 0.0);
5990            for (_VSTD::vector<double>::iterator __i = __p_.begin(), __e = __p_.end();
5991                                                                       __i < __e; ++__i)
5992                *__i /= __s;
5993            vector<double> __t(__p_.size() - 1);
5994            _VSTD::partial_sum(__p_.begin(), __p_.end() - 1, __t.begin());
5995            swap(__p_, __t);
5996        }
5997        else
5998        {
5999            __p_.clear();
6000            __p_.shrink_to_fit();
6001        }
6002    }
6003}
6004
6005template<class _IntType>
6006vector<double>
6007discrete_distribution<_IntType>::param_type::probabilities() const
6008{
6009    size_t __n = __p_.size();
6010    _VSTD::vector<double> __p(__n+1);
6011    _VSTD::adjacent_difference(__p_.begin(), __p_.end(), __p.begin());
6012    if (__n > 0)
6013        __p[__n] = 1 - __p_[__n-1];
6014    else
6015        __p[0] = 1;
6016    return __p;
6017}
6018
6019template<class _IntType>
6020template<class _URNG>
6021_IntType
6022discrete_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
6023{
6024    uniform_real_distribution<double> __gen;
6025    return static_cast<_IntType>(
6026           _VSTD::upper_bound(__p.__p_.begin(), __p.__p_.end(), __gen(__g)) -
6027                                                              __p.__p_.begin());
6028}
6029
6030template <class _CharT, class _Traits, class _IT>
6031basic_ostream<_CharT, _Traits>&
6032operator<<(basic_ostream<_CharT, _Traits>& __os,
6033           const discrete_distribution<_IT>& __x)
6034{
6035    __save_flags<_CharT, _Traits> __lx(__os);
6036    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6037               ios_base::scientific);
6038    _CharT __sp = __os.widen(' ');
6039    __os.fill(__sp);
6040    size_t __n = __x.__p_.__p_.size();
6041    __os << __n;
6042    for (size_t __i = 0; __i < __n; ++__i)
6043        __os << __sp << __x.__p_.__p_[__i];
6044    return __os;
6045}
6046
6047template <class _CharT, class _Traits, class _IT>
6048basic_istream<_CharT, _Traits>&
6049operator>>(basic_istream<_CharT, _Traits>& __is,
6050           discrete_distribution<_IT>& __x)
6051{
6052    __save_flags<_CharT, _Traits> __lx(__is);
6053    __is.flags(ios_base::dec | ios_base::skipws);
6054    size_t __n;
6055    __is >> __n;
6056    vector<double> __p(__n);
6057    for (size_t __i = 0; __i < __n; ++__i)
6058        __is >> __p[__i];
6059    if (!__is.fail())
6060        swap(__x.__p_.__p_, __p);
6061    return __is;
6062}
6063
6064// piecewise_constant_distribution
6065
6066template<class _RealType = double>
6067class _LIBCPP_TEMPLATE_VIS piecewise_constant_distribution
6068{
6069public:
6070    // types
6071    typedef _RealType result_type;
6072
6073    class _LIBCPP_TEMPLATE_VIS param_type
6074    {
6075        vector<result_type> __b_;
6076        vector<result_type> __densities_;
6077        vector<result_type> __areas_;
6078    public:
6079        typedef piecewise_constant_distribution distribution_type;
6080
6081        param_type();
6082        template<class _InputIteratorB, class _InputIteratorW>
6083            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
6084                       _InputIteratorW __fW);
6085#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6086        template<class _UnaryOperation>
6087            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
6088#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6089        template<class _UnaryOperation>
6090            param_type(size_t __nw, result_type __xmin, result_type __xmax,
6091                       _UnaryOperation __fw);
6092        param_type & operator=(const param_type& __rhs);
6093
6094        _LIBCPP_INLINE_VISIBILITY
6095        vector<result_type> intervals() const {return __b_;}
6096        _LIBCPP_INLINE_VISIBILITY
6097        vector<result_type> densities() const {return __densities_;}
6098
6099        friend _LIBCPP_INLINE_VISIBILITY
6100            bool operator==(const param_type& __x, const param_type& __y)
6101            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
6102        friend _LIBCPP_INLINE_VISIBILITY
6103            bool operator!=(const param_type& __x, const param_type& __y)
6104            {return !(__x == __y);}
6105
6106    private:
6107        void __init();
6108
6109        friend class piecewise_constant_distribution;
6110
6111        template <class _CharT, class _Traits, class _RT>
6112        friend
6113        basic_ostream<_CharT, _Traits>&
6114        operator<<(basic_ostream<_CharT, _Traits>& __os,
6115                   const piecewise_constant_distribution<_RT>& __x);
6116
6117        template <class _CharT, class _Traits, class _RT>
6118        friend
6119        basic_istream<_CharT, _Traits>&
6120        operator>>(basic_istream<_CharT, _Traits>& __is,
6121                   piecewise_constant_distribution<_RT>& __x);
6122    };
6123
6124private:
6125    param_type __p_;
6126
6127public:
6128    // constructor and reset functions
6129    _LIBCPP_INLINE_VISIBILITY
6130    piecewise_constant_distribution() {}
6131    template<class _InputIteratorB, class _InputIteratorW>
6132        _LIBCPP_INLINE_VISIBILITY
6133        piecewise_constant_distribution(_InputIteratorB __fB,
6134                                        _InputIteratorB __lB,
6135                                        _InputIteratorW __fW)
6136        : __p_(__fB, __lB, __fW) {}
6137
6138#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6139    template<class _UnaryOperation>
6140        _LIBCPP_INLINE_VISIBILITY
6141        piecewise_constant_distribution(initializer_list<result_type> __bl,
6142                                        _UnaryOperation __fw)
6143        : __p_(__bl, __fw) {}
6144#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6145
6146    template<class _UnaryOperation>
6147        _LIBCPP_INLINE_VISIBILITY
6148        piecewise_constant_distribution(size_t __nw, result_type __xmin,
6149                                        result_type __xmax, _UnaryOperation __fw)
6150        : __p_(__nw, __xmin, __xmax, __fw) {}
6151
6152    _LIBCPP_INLINE_VISIBILITY
6153    explicit piecewise_constant_distribution(const param_type& __p)
6154        : __p_(__p) {}
6155
6156    _LIBCPP_INLINE_VISIBILITY
6157    void reset() {}
6158
6159    // generating functions
6160    template<class _URNG>
6161        _LIBCPP_INLINE_VISIBILITY
6162        result_type operator()(_URNG& __g)
6163        {return (*this)(__g, __p_);}
6164    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
6165
6166    // property functions
6167    _LIBCPP_INLINE_VISIBILITY
6168    vector<result_type> intervals() const {return __p_.intervals();}
6169    _LIBCPP_INLINE_VISIBILITY
6170    vector<result_type> densities() const {return __p_.densities();}
6171
6172    _LIBCPP_INLINE_VISIBILITY
6173    param_type param() const {return __p_;}
6174    _LIBCPP_INLINE_VISIBILITY
6175    void param(const param_type& __p) {__p_ = __p;}
6176
6177    _LIBCPP_INLINE_VISIBILITY
6178    result_type min() const {return __p_.__b_.front();}
6179    _LIBCPP_INLINE_VISIBILITY
6180    result_type max() const {return __p_.__b_.back();}
6181
6182    friend _LIBCPP_INLINE_VISIBILITY
6183        bool operator==(const piecewise_constant_distribution& __x,
6184                        const piecewise_constant_distribution& __y)
6185        {return __x.__p_ == __y.__p_;}
6186    friend _LIBCPP_INLINE_VISIBILITY
6187        bool operator!=(const piecewise_constant_distribution& __x,
6188                           const piecewise_constant_distribution& __y)
6189        {return !(__x == __y);}
6190
6191    template <class _CharT, class _Traits, class _RT>
6192    friend
6193    basic_ostream<_CharT, _Traits>&
6194    operator<<(basic_ostream<_CharT, _Traits>& __os,
6195               const piecewise_constant_distribution<_RT>& __x);
6196
6197    template <class _CharT, class _Traits, class _RT>
6198    friend
6199    basic_istream<_CharT, _Traits>&
6200    operator>>(basic_istream<_CharT, _Traits>& __is,
6201               piecewise_constant_distribution<_RT>& __x);
6202};
6203
6204template<class _RealType>
6205typename piecewise_constant_distribution<_RealType>::param_type &
6206piecewise_constant_distribution<_RealType>::param_type::operator=
6207                                                       (const param_type& __rhs)
6208{
6209//  These can throw
6210    __b_.reserve        (__rhs.__b_.size ());
6211    __densities_.reserve(__rhs.__densities_.size());
6212    __areas_.reserve    (__rhs.__areas_.size());
6213
6214//  These can not throw
6215    __b_         = __rhs.__b_;
6216    __densities_ = __rhs.__densities_;
6217    __areas_     =  __rhs.__areas_;
6218    return *this;
6219}
6220
6221template<class _RealType>
6222void
6223piecewise_constant_distribution<_RealType>::param_type::__init()
6224{
6225    // __densities_ contains non-normalized areas
6226    result_type __total_area = _VSTD::accumulate(__densities_.begin(),
6227                                                __densities_.end(),
6228                                                result_type());
6229    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6230        __densities_[__i] /= __total_area;
6231    // __densities_ contains normalized areas
6232    __areas_.assign(__densities_.size(), result_type());
6233    _VSTD::partial_sum(__densities_.begin(), __densities_.end() - 1,
6234                                                          __areas_.begin() + 1);
6235    // __areas_ contains partial sums of normalized areas: [0, __densities_ - 1]
6236    __densities_.back() = 1 - __areas_.back();  // correct round off error
6237    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6238        __densities_[__i] /= (__b_[__i+1] - __b_[__i]);
6239    // __densities_ now contains __densities_
6240}
6241
6242template<class _RealType>
6243piecewise_constant_distribution<_RealType>::param_type::param_type()
6244    : __b_(2),
6245      __densities_(1, 1.0),
6246      __areas_(1, 0.0)
6247{
6248    __b_[1] = 1;
6249}
6250
6251template<class _RealType>
6252template<class _InputIteratorB, class _InputIteratorW>
6253piecewise_constant_distribution<_RealType>::param_type::param_type(
6254        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
6255    : __b_(__fB, __lB)
6256{
6257    if (__b_.size() < 2)
6258    {
6259        __b_.resize(2);
6260        __b_[0] = 0;
6261        __b_[1] = 1;
6262        __densities_.assign(1, 1.0);
6263        __areas_.assign(1, 0.0);
6264    }
6265    else
6266    {
6267        __densities_.reserve(__b_.size() - 1);
6268        for (size_t __i = 0; __i < __b_.size() - 1; ++__i, ++__fW)
6269            __densities_.push_back(*__fW);
6270        __init();
6271    }
6272}
6273
6274#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6275
6276template<class _RealType>
6277template<class _UnaryOperation>
6278piecewise_constant_distribution<_RealType>::param_type::param_type(
6279        initializer_list<result_type> __bl, _UnaryOperation __fw)
6280    : __b_(__bl.begin(), __bl.end())
6281{
6282    if (__b_.size() < 2)
6283    {
6284        __b_.resize(2);
6285        __b_[0] = 0;
6286        __b_[1] = 1;
6287        __densities_.assign(1, 1.0);
6288        __areas_.assign(1, 0.0);
6289    }
6290    else
6291    {
6292        __densities_.reserve(__b_.size() - 1);
6293        for (size_t __i = 0; __i < __b_.size() - 1; ++__i)
6294            __densities_.push_back(__fw((__b_[__i+1] + __b_[__i])*.5));
6295        __init();
6296    }
6297}
6298
6299#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6300
6301template<class _RealType>
6302template<class _UnaryOperation>
6303piecewise_constant_distribution<_RealType>::param_type::param_type(
6304        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
6305    : __b_(__nw == 0 ? 2 : __nw + 1)
6306{
6307    size_t __n = __b_.size() - 1;
6308    result_type __d = (__xmax - __xmin) / __n;
6309    __densities_.reserve(__n);
6310    for (size_t __i = 0; __i < __n; ++__i)
6311    {
6312        __b_[__i] = __xmin + __i * __d;
6313        __densities_.push_back(__fw(__b_[__i] + __d*.5));
6314    }
6315    __b_[__n] = __xmax;
6316    __init();
6317}
6318
6319template<class _RealType>
6320template<class _URNG>
6321_RealType
6322piecewise_constant_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
6323{
6324    typedef uniform_real_distribution<result_type> _Gen;
6325    result_type __u = _Gen()(__g);
6326    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
6327                                      __u) - __p.__areas_.begin() - 1;
6328    return (__u - __p.__areas_[__k]) / __p.__densities_[__k] + __p.__b_[__k];
6329}
6330
6331template <class _CharT, class _Traits, class _RT>
6332basic_ostream<_CharT, _Traits>&
6333operator<<(basic_ostream<_CharT, _Traits>& __os,
6334           const piecewise_constant_distribution<_RT>& __x)
6335{
6336    __save_flags<_CharT, _Traits> __lx(__os);
6337    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6338               ios_base::scientific);
6339    _CharT __sp = __os.widen(' ');
6340    __os.fill(__sp);
6341    size_t __n = __x.__p_.__b_.size();
6342    __os << __n;
6343    for (size_t __i = 0; __i < __n; ++__i)
6344        __os << __sp << __x.__p_.__b_[__i];
6345    __n = __x.__p_.__densities_.size();
6346    __os << __sp << __n;
6347    for (size_t __i = 0; __i < __n; ++__i)
6348        __os << __sp << __x.__p_.__densities_[__i];
6349    __n = __x.__p_.__areas_.size();
6350    __os << __sp << __n;
6351    for (size_t __i = 0; __i < __n; ++__i)
6352        __os << __sp << __x.__p_.__areas_[__i];
6353    return __os;
6354}
6355
6356template <class _CharT, class _Traits, class _RT>
6357basic_istream<_CharT, _Traits>&
6358operator>>(basic_istream<_CharT, _Traits>& __is,
6359           piecewise_constant_distribution<_RT>& __x)
6360{
6361    typedef piecewise_constant_distribution<_RT> _Eng;
6362    typedef typename _Eng::result_type result_type;
6363    __save_flags<_CharT, _Traits> __lx(__is);
6364    __is.flags(ios_base::dec | ios_base::skipws);
6365    size_t __n;
6366    __is >> __n;
6367    vector<result_type> __b(__n);
6368    for (size_t __i = 0; __i < __n; ++__i)
6369        __is >> __b[__i];
6370    __is >> __n;
6371    vector<result_type> __densities(__n);
6372    for (size_t __i = 0; __i < __n; ++__i)
6373        __is >> __densities[__i];
6374    __is >> __n;
6375    vector<result_type> __areas(__n);
6376    for (size_t __i = 0; __i < __n; ++__i)
6377        __is >> __areas[__i];
6378    if (!__is.fail())
6379    {
6380        swap(__x.__p_.__b_, __b);
6381        swap(__x.__p_.__densities_, __densities);
6382        swap(__x.__p_.__areas_, __areas);
6383    }
6384    return __is;
6385}
6386
6387// piecewise_linear_distribution
6388
6389template<class _RealType = double>
6390class _LIBCPP_TEMPLATE_VIS piecewise_linear_distribution
6391{
6392public:
6393    // types
6394    typedef _RealType result_type;
6395
6396    class _LIBCPP_TEMPLATE_VIS param_type
6397    {
6398        vector<result_type> __b_;
6399        vector<result_type> __densities_;
6400        vector<result_type> __areas_;
6401    public:
6402        typedef piecewise_linear_distribution distribution_type;
6403
6404        param_type();
6405        template<class _InputIteratorB, class _InputIteratorW>
6406            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
6407                       _InputIteratorW __fW);
6408#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6409        template<class _UnaryOperation>
6410            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
6411#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6412        template<class _UnaryOperation>
6413            param_type(size_t __nw, result_type __xmin, result_type __xmax,
6414                       _UnaryOperation __fw);
6415        param_type & operator=(const param_type& __rhs);
6416
6417        _LIBCPP_INLINE_VISIBILITY
6418        vector<result_type> intervals() const {return __b_;}
6419        _LIBCPP_INLINE_VISIBILITY
6420        vector<result_type> densities() const {return __densities_;}
6421
6422        friend _LIBCPP_INLINE_VISIBILITY
6423            bool operator==(const param_type& __x, const param_type& __y)
6424            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
6425        friend _LIBCPP_INLINE_VISIBILITY
6426            bool operator!=(const param_type& __x, const param_type& __y)
6427            {return !(__x == __y);}
6428
6429    private:
6430        void __init();
6431
6432        friend class piecewise_linear_distribution;
6433
6434        template <class _CharT, class _Traits, class _RT>
6435        friend
6436        basic_ostream<_CharT, _Traits>&
6437        operator<<(basic_ostream<_CharT, _Traits>& __os,
6438                   const piecewise_linear_distribution<_RT>& __x);
6439
6440        template <class _CharT, class _Traits, class _RT>
6441        friend
6442        basic_istream<_CharT, _Traits>&
6443        operator>>(basic_istream<_CharT, _Traits>& __is,
6444                   piecewise_linear_distribution<_RT>& __x);
6445    };
6446
6447private:
6448    param_type __p_;
6449
6450public:
6451    // constructor and reset functions
6452    _LIBCPP_INLINE_VISIBILITY
6453    piecewise_linear_distribution() {}
6454    template<class _InputIteratorB, class _InputIteratorW>
6455        _LIBCPP_INLINE_VISIBILITY
6456        piecewise_linear_distribution(_InputIteratorB __fB,
6457                                      _InputIteratorB __lB,
6458                                      _InputIteratorW __fW)
6459        : __p_(__fB, __lB, __fW) {}
6460
6461#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6462    template<class _UnaryOperation>
6463        _LIBCPP_INLINE_VISIBILITY
6464        piecewise_linear_distribution(initializer_list<result_type> __bl,
6465                                      _UnaryOperation __fw)
6466        : __p_(__bl, __fw) {}
6467#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6468
6469    template<class _UnaryOperation>
6470        _LIBCPP_INLINE_VISIBILITY
6471        piecewise_linear_distribution(size_t __nw, result_type __xmin,
6472                                      result_type __xmax, _UnaryOperation __fw)
6473        : __p_(__nw, __xmin, __xmax, __fw) {}
6474
6475    _LIBCPP_INLINE_VISIBILITY
6476    explicit piecewise_linear_distribution(const param_type& __p)
6477        : __p_(__p) {}
6478
6479    _LIBCPP_INLINE_VISIBILITY
6480    void reset() {}
6481
6482    // generating functions
6483    template<class _URNG>
6484        _LIBCPP_INLINE_VISIBILITY
6485        result_type operator()(_URNG& __g)
6486        {return (*this)(__g, __p_);}
6487    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
6488
6489    // property functions
6490    _LIBCPP_INLINE_VISIBILITY
6491    vector<result_type> intervals() const {return __p_.intervals();}
6492    _LIBCPP_INLINE_VISIBILITY
6493    vector<result_type> densities() const {return __p_.densities();}
6494
6495    _LIBCPP_INLINE_VISIBILITY
6496    param_type param() const {return __p_;}
6497    _LIBCPP_INLINE_VISIBILITY
6498    void param(const param_type& __p) {__p_ = __p;}
6499
6500    _LIBCPP_INLINE_VISIBILITY
6501    result_type min() const {return __p_.__b_.front();}
6502    _LIBCPP_INLINE_VISIBILITY
6503    result_type max() const {return __p_.__b_.back();}
6504
6505    friend _LIBCPP_INLINE_VISIBILITY
6506        bool operator==(const piecewise_linear_distribution& __x,
6507                        const piecewise_linear_distribution& __y)
6508        {return __x.__p_ == __y.__p_;}
6509    friend _LIBCPP_INLINE_VISIBILITY
6510        bool operator!=(const piecewise_linear_distribution& __x,
6511                        const piecewise_linear_distribution& __y)
6512        {return !(__x == __y);}
6513
6514    template <class _CharT, class _Traits, class _RT>
6515    friend
6516    basic_ostream<_CharT, _Traits>&
6517    operator<<(basic_ostream<_CharT, _Traits>& __os,
6518               const piecewise_linear_distribution<_RT>& __x);
6519
6520    template <class _CharT, class _Traits, class _RT>
6521    friend
6522    basic_istream<_CharT, _Traits>&
6523    operator>>(basic_istream<_CharT, _Traits>& __is,
6524               piecewise_linear_distribution<_RT>& __x);
6525};
6526
6527template<class _RealType>
6528typename piecewise_linear_distribution<_RealType>::param_type &
6529piecewise_linear_distribution<_RealType>::param_type::operator=
6530                                                       (const param_type& __rhs)
6531{
6532//  These can throw
6533    __b_.reserve        (__rhs.__b_.size ());
6534    __densities_.reserve(__rhs.__densities_.size());
6535    __areas_.reserve    (__rhs.__areas_.size());
6536
6537//  These can not throw
6538    __b_         = __rhs.__b_;
6539    __densities_ = __rhs.__densities_;
6540    __areas_     =  __rhs.__areas_;
6541    return *this;
6542}
6543
6544
6545template<class _RealType>
6546void
6547piecewise_linear_distribution<_RealType>::param_type::__init()
6548{
6549    __areas_.assign(__densities_.size() - 1, result_type());
6550    result_type _Sp = 0;
6551    for (size_t __i = 0; __i < __areas_.size(); ++__i)
6552    {
6553        __areas_[__i] = (__densities_[__i+1] + __densities_[__i]) *
6554                        (__b_[__i+1] - __b_[__i]) * .5;
6555        _Sp += __areas_[__i];
6556    }
6557    for (size_t __i = __areas_.size(); __i > 1;)
6558    {
6559        --__i;
6560        __areas_[__i] = __areas_[__i-1] / _Sp;
6561    }
6562    __areas_[0] = 0;
6563    for (size_t __i = 1; __i < __areas_.size(); ++__i)
6564        __areas_[__i] += __areas_[__i-1];
6565    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6566        __densities_[__i] /= _Sp;
6567}
6568
6569template<class _RealType>
6570piecewise_linear_distribution<_RealType>::param_type::param_type()
6571    : __b_(2),
6572      __densities_(2, 1.0),
6573      __areas_(1, 0.0)
6574{
6575    __b_[1] = 1;
6576}
6577
6578template<class _RealType>
6579template<class _InputIteratorB, class _InputIteratorW>
6580piecewise_linear_distribution<_RealType>::param_type::param_type(
6581        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
6582    : __b_(__fB, __lB)
6583{
6584    if (__b_.size() < 2)
6585    {
6586        __b_.resize(2);
6587        __b_[0] = 0;
6588        __b_[1] = 1;
6589        __densities_.assign(2, 1.0);
6590        __areas_.assign(1, 0.0);
6591    }
6592    else
6593    {
6594        __densities_.reserve(__b_.size());
6595        for (size_t __i = 0; __i < __b_.size(); ++__i, ++__fW)
6596            __densities_.push_back(*__fW);
6597        __init();
6598    }
6599}
6600
6601#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6602
6603template<class _RealType>
6604template<class _UnaryOperation>
6605piecewise_linear_distribution<_RealType>::param_type::param_type(
6606        initializer_list<result_type> __bl, _UnaryOperation __fw)
6607    : __b_(__bl.begin(), __bl.end())
6608{
6609    if (__b_.size() < 2)
6610    {
6611        __b_.resize(2);
6612        __b_[0] = 0;
6613        __b_[1] = 1;
6614        __densities_.assign(2, 1.0);
6615        __areas_.assign(1, 0.0);
6616    }
6617    else
6618    {
6619        __densities_.reserve(__b_.size());
6620        for (size_t __i = 0; __i < __b_.size(); ++__i)
6621            __densities_.push_back(__fw(__b_[__i]));
6622        __init();
6623    }
6624}
6625
6626#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
6627
6628template<class _RealType>
6629template<class _UnaryOperation>
6630piecewise_linear_distribution<_RealType>::param_type::param_type(
6631        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
6632    : __b_(__nw == 0 ? 2 : __nw + 1)
6633{
6634    size_t __n = __b_.size() - 1;
6635    result_type __d = (__xmax - __xmin) / __n;
6636    __densities_.reserve(__b_.size());
6637    for (size_t __i = 0; __i < __n; ++__i)
6638    {
6639        __b_[__i] = __xmin + __i * __d;
6640        __densities_.push_back(__fw(__b_[__i]));
6641    }
6642    __b_[__n] = __xmax;
6643    __densities_.push_back(__fw(__b_[__n]));
6644    __init();
6645}
6646
6647template<class _RealType>
6648template<class _URNG>
6649_RealType
6650piecewise_linear_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
6651{
6652    typedef uniform_real_distribution<result_type> _Gen;
6653    result_type __u = _Gen()(__g);
6654    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
6655                                      __u) - __p.__areas_.begin() - 1;
6656    __u -= __p.__areas_[__k];
6657    const result_type __dk = __p.__densities_[__k];
6658    const result_type __dk1 = __p.__densities_[__k+1];
6659    const result_type __deltad = __dk1 - __dk;
6660    const result_type __bk = __p.__b_[__k];
6661    if (__deltad == 0)
6662        return __u / __dk + __bk;
6663    const result_type __bk1 = __p.__b_[__k+1];
6664    const result_type __deltab = __bk1 - __bk;
6665    return (__bk * __dk1 - __bk1 * __dk +
6666        _VSTD::sqrt(__deltab * (__deltab * __dk * __dk + 2 * __deltad * __u))) /
6667        __deltad;
6668}
6669
6670template <class _CharT, class _Traits, class _RT>
6671basic_ostream<_CharT, _Traits>&
6672operator<<(basic_ostream<_CharT, _Traits>& __os,
6673           const piecewise_linear_distribution<_RT>& __x)
6674{
6675    __save_flags<_CharT, _Traits> __lx(__os);
6676    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6677               ios_base::scientific);
6678    _CharT __sp = __os.widen(' ');
6679    __os.fill(__sp);
6680    size_t __n = __x.__p_.__b_.size();
6681    __os << __n;
6682    for (size_t __i = 0; __i < __n; ++__i)
6683        __os << __sp << __x.__p_.__b_[__i];
6684    __n = __x.__p_.__densities_.size();
6685    __os << __sp << __n;
6686    for (size_t __i = 0; __i < __n; ++__i)
6687        __os << __sp << __x.__p_.__densities_[__i];
6688    __n = __x.__p_.__areas_.size();
6689    __os << __sp << __n;
6690    for (size_t __i = 0; __i < __n; ++__i)
6691        __os << __sp << __x.__p_.__areas_[__i];
6692    return __os;
6693}
6694
6695template <class _CharT, class _Traits, class _RT>
6696basic_istream<_CharT, _Traits>&
6697operator>>(basic_istream<_CharT, _Traits>& __is,
6698           piecewise_linear_distribution<_RT>& __x)
6699{
6700    typedef piecewise_linear_distribution<_RT> _Eng;
6701    typedef typename _Eng::result_type result_type;
6702    __save_flags<_CharT, _Traits> __lx(__is);
6703    __is.flags(ios_base::dec | ios_base::skipws);
6704    size_t __n;
6705    __is >> __n;
6706    vector<result_type> __b(__n);
6707    for (size_t __i = 0; __i < __n; ++__i)
6708        __is >> __b[__i];
6709    __is >> __n;
6710    vector<result_type> __densities(__n);
6711    for (size_t __i = 0; __i < __n; ++__i)
6712        __is >> __densities[__i];
6713    __is >> __n;
6714    vector<result_type> __areas(__n);
6715    for (size_t __i = 0; __i < __n; ++__i)
6716        __is >> __areas[__i];
6717    if (!__is.fail())
6718    {
6719        swap(__x.__p_.__b_, __b);
6720        swap(__x.__p_.__densities_, __densities);
6721        swap(__x.__p_.__areas_, __areas);
6722    }
6723    return __is;
6724}
6725
6726_LIBCPP_END_NAMESPACE_STD
6727
6728#endif  // _LIBCPP_RANDOM
6729