STD::SUBTRACT_WITH_CARRY_ENGINE(3cxx)

📦
version 14-20240412 · 20 versions
, in ubuntu noble

💖 NAME 💖

std::subtract_with_carry_engine< _UIntType, __w, __s, __r > — the Marsaglia-Zaman generator. This is the 3cxx manual page for it, bestie, and it's giving very specific random-number-engine energy. 🎀

🌈 SYNOPSIS 🌈

#include <random>

✨ Public Types ✨

  • typedef _UIntType result_type

💅 Public Member Functions 💅

  • template<typename _Sseq , typename = _If_seed_seq<_Sseq>> subtract_with_carry_engine (_Sseq &__q) — constructs a subtract_with_carry_engine random number engine seeded from the seed sequence __q.
  • subtract_with_carry_engine (result_type __sd) — constructs an explicitly seeded subtract_with_carry_engine random number generator.
  • void discard (unsigned long long __z) — discards a sequence of random numbers.
  • result_type operator() () — gets the next random number in the sequence.
  • template<typename _Sseq > _If_seed_seq< _Sseq > seed (_Sseq &__q) — seeds the initial state $x_0$ of the % subtract_with_carry_engine random number generator.
  • template<typename _Sseq > auto seed (_Sseq &__q) -> _If_seed_seq< _Sseq > — the synopsis lists this overload too, with no extra blurb attached, so no invented tea here. 💅
  • void seed (result_type __sd=0u) — seeds the initial state $x_0$ of the random number generator.

🦋 Static Public Member Functions 🦋

  • static constexpr result_type max () — gets the inclusive maximum value of the range of random integers returned by this generator.
  • static constexpr result_type min () — gets the inclusive minimum value of the range of random integers returned by this generator.

🍓 Static Public Attributes 🍓

  • static constexpr uint_least32_t default_seed
  • static constexpr size_t long_lag
  • static constexpr size_t short_lag
  • static constexpr size_t word_size

🧚 Friends 🧚

  • template<typename _UIntType1 , size_t __w1, size_t __s1, size_t __r1, typename _CharT , typename _Traits > std::basic_ostream< _CharT, _Traits > & operator<< (std::basic_ostream< _CharT, _Traits > &__os, const std::subtract_with_carry_engine< _UIntType1, __w1, __s1, __r1 > &__x) — inserts the current state of a % subtract_with_carry_engine random number generator engine __x into the output stream __os.
  • bool operator== (const subtract_with_carry_engine &__lhs, const subtract_with_carry_engine &__rhs) — compares two % subtract_with_carry_engine random number generator objects of the same type for equality.
  • template<typename _UIntType1 , size_t __w1, size_t __s1, size_t __r1, typename _CharT , typename _Traits > std::basic_istream< _CharT, _Traits > & operator>> (std::basic_istream< _CharT, _Traits > &__is, std::subtract_with_carry_engine< _UIntType1, __w1, __s1, __r1 > &__x) — extracts the current state of a % subtract_with_carry_engine random number generator engine __x from the input stream __is.

👑 Detailed Description 👑

template<typename _UIntType, size_t __w, size_t __s, size_t __r>
class std::subtract_with_carry_engine< _UIntType, __w, __s, __r >"The
Marsaglia-Zaman generator.

Okay so this is the Marsaglia-Zaman generator, and it's a model of a Generalized Fibonacci discrete random number generator, sometimes referred to as the SWC generator.

It's a discrete random number generator that produces pseudorandom numbers using — and yes, the source has a stray o hanging around right before the formula, keeping it real:

x_{i}tarrow(x_{i - s} - x_{i - r} - carry_{i-1}) d ]

The size of the state is $r$ and the maximum period of the generator is $(m^r - m^s - 1)$.

Since: C++11

🧚 Member Typedef Documentation 🧚

template<typename _UIntType , size_t __w , size_t __s , size_t __r> typedef _UIntType std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::result_type

The type of the generated random value. Slay. ✨

🎀 Constructor & Destructor Documentation 🎀

Explicit seeded constructor

template<typename _UIntType , size_t __w , size_t __s , size_t __r>
std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::subtract_with_carry_engine (result_type __sd) [inline],  [explicit]

Constructs an explicitly seeded subtract_with_carry_engine random number generator.

References std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::seed().

Seed-sequence constructor

template<typename _UIntType , size_t __w , size_t __s , size_t __r>
template<typename _Sseq , typename  = _If_seed_seq<_Sseq>>
std::subtract_with_carry_engine< _UIntType, __w, __s, __r
>::subtract_with_carry_engine (_Sseq & __q) [inline],  [explicit]

Constructs a subtract_with_carry_engine random number engine seeded from the seed sequence __q.

Parameters

  • __q the seed sequence.

References std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::seed().

💜 Member Function Documentation 💜

discard

template<typename _UIntType , size_t __w , size_t __s , size_t __r> void
std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::discard
(unsigned long long __z) [inline]

Discard a sequence of random numbers.

max

template<typename _UIntType , size_t __w , size_t __s , size_t __r> static
constexpr result_type std::subtract_with_carry_engine< _UIntType, __w,
__s, __r >::max () [inline],  [static],  [constexpr]

Gets the inclusive maximum value of the range of random integers returned by this generator.

min

template<typename _UIntType , size_t __w , size_t __s , size_t __r> static
constexpr result_type std::subtract_with_carry_engine< _UIntType, __w,
__s, __r >::min () [inline],  [static],  [constexpr]

Gets the inclusive minimum value of the range of random integers returned by this generator.

operator()

template<typename _UIntType , size_t __w , size_t __s , size_t __r>
subtract_with_carry_engine< _UIntType, __w, __s, __r >::result_type
std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::operator()
()

Gets the next random number in the sequence.

seed(_Sseq & __q)

template<typename _UIntType , size_t __w , size_t __s , size_t __r>
template<typename _Sseq > _If_seed_seq< _Sseq >
std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::seed (_Sseq
& __q)

Seeds the initial state $x_0$ of the % subtract_with_carry_engine random number generator.

seed(result_type __sd = 0u)

template<typename _UIntType , size_t __w , size_t __s , size_t __r> void
std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::seed
(result_type __sd = 0u)

Seeds the initial state $x_0$ of the random number generator.

N1688[4.19] modifies this as follows. If __value == 0, sets value to
19780503. In any case, with a linear congruential generator lcg(i)
having parameters $ m_{lcg} = 2147483563, a_{lcg} = 40014, c_olcg} = 0,
and lcgo0) = value $, sets $ x_{-r} ots x_{-1} $ to $ lcg(1) d ots
lcg(r) d $ respectively. If $ x_{-1} = 0 $ set carry to 1, otherwise
sets carry to 0.

Referenced by std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::subtract_with_carry_engine(), and std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::subtract_with_carry_engine().

operator<<

template<typename _UIntType , size_t __w , size_t __s , size_t __r>
template<typename _UIntType1 , size_t __w1, size_t __s1, size_t __r1,
typename _CharT , typename _Traits > std::basic_ostream< _CharT, _Traits
> & operator<< (std::basic_ostream< _CharT, _Traits > & __os, const
std::subtract_with_carry_engine< _UIntType1, __w1, __s1, __r1 > & __x)
[friend]

Inserts the current state of a % subtract_with_carry_engine random number generator engine __x into the output stream __os.

Parameters

  • __os An output stream.
  • __x A % subtract_with_carry_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 __s , size_t __r> bool
operator== (const subtract_with_carry_engine< _UIntType, __w, __s, __r >
& __lhs, const subtract_with_carry_engine< _UIntType, __w, __s, __r > &
__rhs) [friend]

Compares two % subtract_with_carry_engine random number generator objects of the same type for equality.

Parameters

  • __lhs A % subtract_with_carry_engine random number generator object.
  • __rhs Another % subtract_with_carry_engine random number generator object.

Returns

true if the infinite sequences of generated values would be equal, false otherwise.

operator>>

template<typename _UIntType , size_t __w , size_t __s , size_t __r>
template<typename _UIntType1 , size_t __w1, size_t __s1, size_t __r1,
typename _CharT , typename _Traits > std::basic_istream< _CharT, _Traits
> & operator>> (std::basic_istream< _CharT, _Traits > & __is,
std::subtract_with_carry_engine< _UIntType1, __w1, __s1, __r1 > & __x)
[friend]

Extracts the current state of a % subtract_with_carry_engine random number generator engine __x from the input stream __is.

Parameters

  • __is An input stream.
  • __x A % subtract_with_carry_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.

And that's the whole page, bestie 🫶. Source/version tea: this one's generated automatically by Doxygen for libstdc++ from the source code, and the footer is the usual truncated 3cxx manual-footer vibe for the std::subtract_...__w, __s, __r > page. No actual date is printed on it, so no cap — that's literally all the footer gives us. 💅✨

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