STD::MERSENNE_TWISTER_ENGINE(3cxx)

📦
version 14-20240412 · 16 versions
, in ubuntu noble

💖 NAME 💖

okay so bestie, welcome to std::mersenne_twister_engine — the legendary Mersenne Twister random number engine from libstdc++ (that's the <pink>3cxx</pink> manual, iykyk) 💅

std::mersenne_twister_engine< _UIntType, __w, __n, __m, __r, __a, __u,
    __d, __s, __b, __t, __c, __l, __f >

That's fourteen template parameters babe. Fourteen. She's extra and we love her for it 💜

✨ SYNOPSIS ✨

First things first, the ritual:

#include <random>

🎀 Public Types 🎀

  • typedef _UIntType result_type — the type of the random value she's gonna hand you ✨

💅 Public Member Functions 💅

  • template<typename _Sseq , typename = _If_seed_seq<_Sseq>> mersenne_twister_engine (_Sseq &__q) — builds a mersenne_twister_engine random number generator engine, seeded from the seed sequence __q 🫶
  • mersenne_twister_engine (result_type __sd) — the other constructor, no description given, she's mysterious like that 🙈
  • void discard (unsigned long long __z) — throws away a sequence of random numbers, extremely "not me deleting my ex's number" energy 💀
  • result_type operator() () — the main character. generates a value 🎀
  • template<typename _Sseq > _If_seed_seq< _Sseq > seed (_Sseq &__q) — reseeds from a seed sequence
  • template<typename _Sseq > auto seed (_Sseq &__q) -> _If_seed_seq< _Sseq > — same vibe, trailing-return-type fit ✅
  • void seed (result_type __sd=default_seed) — reseeds from a plain value, and if you don't pass one she falls back to default_seed (classic) 🌸

🦋 Static Public Member Functions 🦋

  • static constexpr result_type max () — gets the biggest possible value in the output range, no cap 📈
  • static constexpr result_type min () — gets the smallest possible value in the output range 🧚

⭐ Static Public Attributes ⭐

All of these are static constexpr babe, they're constants, they're not changing for anyone:

  • static constexpr result_type default_seed — the default seed 💫
  • static constexpr result_type initialization_multiplier — the init multiplier
  • static constexpr size_t mask_bits — mask bits 🔥
  • static constexpr size_t shift_size — shift size
  • static constexpr size_t state_size — how big the state is
  • static constexpr result_type tempering_b — tempering b
  • static constexpr result_type tempering_c — tempering c
  • static constexpr result_type tempering_d — tempering d
  • static constexpr size_t tempering_l — tempering l
  • static constexpr size_t tempering_s — tempering s
  • static constexpr size_t tempering_t — tempering t
  • static constexpr size_t tempering_u — tempering u
  • static constexpr size_t word_size — the word size
  • static constexpr result_type xor_mask — the xor mask 🌈

🫶 Friends 🫶

  • template<typename _UIntType1 , size_t __w1, size_t __n1, size_t __m1, size_t __r1, _UIntType1 __a1, size_t __u1, _UIntType1 __d1, size_t __s1, _UIntType1 __b1, size_t __t1, _UIntType1 __c1, size_t __l1, _UIntType1 __f1, typename _CharT , typename _Traits > std::basic_ostream< _CharT, _Traits > & operator<< (std::basic_ostream< _CharT, _Traits > &__os, const std::mersenne_twister_engine< _UIntType1, __w1, __n1, __m1, __r1, __a1, __u1, __d1, __s1, __b1, __t1, __c1, __l1, __f1 > &__x) — inserts the current state of a mersenne_twister_engine random number generator engine __x into the output stream __os 💌
  • bool operator== (const mersenne_twister_engine &__lhs, const mersenne_twister_engine &__rhs) — compares two mersenne_twister_engine random number generator objects of the same type for equality ⚖️
  • template<typename _UIntType1 , size_t __w1, size_t __n1, size_t __m1, size_t __r1, _UIntType1 __a1, size_t __u1, _UIntType1 __d1, size_t __s1, _UIntType1 __b1, size_t __t1, _UIntType1 __c1, size_t __l1, _UIntType1 __f1, typename _CharT , typename _Traits > std::basic_istream< _CharT, _Traits > & operator>> (std::basic_istream< _CharT, _Traits > &__is, std::mersenne_twister_engine< _UIntType1, __w1, __n1, __m1, __r1, __a1, __u1, __d1, __s1, __b1, __t1, __c1, __l1, __f1 > &__x) — extracts the current state of a mersenne_twister_engine random number generator engine __x from the input stream __is 💌

🔥 DETAILED DESCRIPTION 🔥

template<typename _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
    _UIntType __a, size_t __u, _UIntType __d, size_t __s, _UIntType __b,
    size_t __t, _UIntType __c, size_t __l, _UIntType __f>
    class std::mersenne_twister_engine< _UIntType, __w, __n, __m, __r, __a,
    __u, __d, __s, __b, __t, __c, __l, __f >

So what is she? She's a "A generalized feedback shift register discrete random number generator." ✨

This algorithm avoids multiplication and division and is designed to be friendly to a pipelined architecture. If the parameters are chosen correctly, this generator will produce numbers with a very long period and fairly good apparent entropy — although still not cryptographically strong. So like, do not use her for your passwords bestie, she said so herself 😭

The best way to use this generator is with the predefined mt19937 class. That's the whole tip, take it or leave it 💅

This algorithm was originally invented by Makoto Matsumoto and Takuji Nishimura. kings 👑👑

🌸 Template Parameters 🌸

Every single one, annotated, because she deserves it:

  • __w — Word size, the number of bits in each element of the state vector.
  • __n — The degree of recursion.
  • __m — The period parameter.
  • __r — The separation point bit index.
  • __a — The last row of the twist matrix.
  • __u — The first right-shift tempering matrix parameter.
  • __d — The first right-shift tempering matrix mask.
  • __s — The first left-shift tempering matrix parameter.
  • __b — The first left-shift tempering matrix mask.
  • __t — The second left-shift tempering matrix parameter.
  • __c — The second left-shift tempering matrix mask.
  • __l — The second right-shift tempering matrix parameter.
  • __f — Initialization multiplier.

🦋 Since 🦋

C++11 — vintage but make it iconic 🎀

🎀 MEMBER TYPEDEF DOCUMENTATION 🎀

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f > typedef
    _UIntType std::mersenne_twister_engine< _UIntType, __w, __n, __m, __r,
    __a, __u, __d, __s, __b, __t, __c, __l, __f >::result_type

The type of the generated random value. that's it, that's the whole typedef, and honestly she ate ✨

🌈 CONSTRUCTOR & DESTRUCTOR DOCUMENTATION 🌈

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f >
    template<typename _Sseq , typename  = _If_seed_seq<_Sseq>>
    std::mersenne_twister_engine< _UIntType, __w, __n, __m, __r, __a, __u,
    __d, __s, __b, __t, __c, __l, __f >::mersenne_twister_engine (_Sseq &
    __q) [inline],  [explicit]

Constructs a mersenne_twister_engine random number generator engine seeded from the seed sequence __q 🌱

Parameters

  • __q — the seed sequence.
heads up: she's [explicit] so no accidental implicit conversions sneaking in, we love a boundary-setting queen 🫶

💅 MEMBER FUNCTION DOCUMENTATION 💅

discard

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f > void
    std::mersenne_twister_engine< _UIntType, __w, __n, __m, __r, __a, __u,
    __d, __s, __b, __t, __c, __l, __f >::discard (unsigned long long __z)

Discard a sequence of random numbers. bye bye numbers, don't let the door hit you 💀

max

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f > static
    constexpr result_type std::mersenne_twister_engine< _UIntType, __w, __n,
    __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f >::max ()
    [inline],  [static],  [constexpr]

Gets the largest possible value in the output range. the ceiling, the limit, the "you can't sit with us" 🫶

min

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f > static
    constexpr result_type std::mersenne_twister_engine< _UIntType, __w, __n,
    __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f >::min ()
    [inline],  [static],  [constexpr]

Gets the smallest possible value in the output range. the floor, she's humble 💜

operator<<

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f >
    template<typename _UIntType1 , size_t __w1 , size_t __n1 , size_t __m1,
    size_t __r1 , _UIntType1 __a1 , size_t __u1 , _UIntType1 __d1 , size_t __s1 ,
    _UIntType1 __b1 , size_t __t1 , _UIntType1 __c1 , size_t __l1 , _UIntType1
    __f1 , typename _CharT , typename _Traits > std::basic_ostream< _CharT,
    _Traits > & operator<< (std::basic_ostream< _CharT, _Traits > & __os,
    const std::mersenne_twister_engine< _UIntType1, __w1, __n1, __m1, __r1,
    __a1, __u1, __d1, __s1, __b1, __t1, __c1, __l1, __f1 > & __x) [friend]

Inserts the current state of a mersenne_twister_engine random number generator engine __x into the output stream __os. state dump but make it cute 📤

Parameters

  • __os — An output stream.
  • __x — A mersenne_twister_engine random number generator engine.

Returns

The output stream with the state of __x inserted or in an error state.

operator==

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f > bool
    operator== (const mersenne_twister_engine< _UIntType, __w, __n, __m,
    __r, __a, __u, __d, __s, __b, __t, __c, __l, __f > & __lhs, const
    mersenne_twister_engine< _UIntType, __w, __n, __m, __r, __a, __u, __d,
    __s, __b, __t, __c, __l, __f > & __rhs) [friend]

Compares two mersenne_twister_engine random number generator objects of the same type for equality. are they the same girl? let's find out ⚖️

Parameters

  • __lhs — A mersenne_twister_engine random number generator object.
  • __rhs — Another mersenne_twister_engine random number generator object.

Returns

true if the infinite sequences of generated values would be equal, false otherwise. (infinite. sequences. no biggie 💀)

operator>>

template<typename _UIntType , size_t __w , size_t __n , size_t __m , size_t
    __r , _UIntType __a , size_t __u , _UIntType __d , size_t __s , _UIntType
    __b , size_t __t , _UIntType __c , size_t __l , _UIntType __f >
    template<typename _UIntType1 , size_t __w1 , size_t __n1 , size_t __m1,
    size_t __r1 , _UIntType1 __a1 , size_t __u1 , _UIntType1 __d1 , size_t __s1 ,
    _UIntType1 __b1 , size_t __t1 , _UIntType1 __c1 , size_t __l1 , _UIntType1
    __f1 , typename _CharT , typename _Traits > std::basic_istream< _CharT,
    _Traits > & operator>> (std::basic_istream< _CharT, _Traits > & __is,
    std::mersenne_twister_engine< _UIntType1, __w1, __n1, __m1, __r1, __a1,
    __u1, __d1, __s1, __b1, __t1, __c1, __l1, __f1 > & __x) [friend]

Extracts the current state of a mersenne_twister_engine random number generator engine __x from the input stream __is. reading her state back in, consent era 📥

Parameters

  • __is — An input stream.
  • __x — A mersenne_twister_engine random number generator engine.

Returns

The input stream with the state of __x extracted or in an error state.

💜 AUTHOR 💜

Generated automatically by Doxygen for libstdc++ from the source code. yes she was auto-generated and she's still serving looks, the algorithm ate 🔥

okay that's the whole page bestie, mwah 💋 this was page <pink>libststd::mersenne_t...__c, __l, __f >(3cxx)</pink> from the libstdc++ manual, the <pink>3cxx</pink> collection — go seed something iconic and remember: she's got a long period but she is not cryptographically strong 🌈✨🎀🫶

📦 where this page comes from