std::subtract_with_carry_engine man page

std::subtract_with_carry_engine< _UIntType, __w, __s, __r > — The Marsaglia-Zaman generator.

Synopsis

Public Types

typedef _UIntType result_type

Public Member Functions

subtract_with_carry_engine (result_type __sd=default_seed)
Constructs an explicitly seeded % subtract_with_carry_engine random number generator.
template<typename _Sseq , typename = typename std::enable_if<!std::is_same<_Sseq, subtract_with_carry_engine>::value> ::type> subtract_with_carry_engine (_Sseq &__q)
Constructs a subtract_with_carry_engine random number engine seeded from the seed sequence __q.
void discard (unsigned long long __z)
Discard a sequence of random numbers.
result_type operator() ()
Gets the next random number in the sequence.
void seed (result_type __sd=default_seed)
Seeds the initial state $x_0$ of the random number generator.
template<typename _Sseq > std::enable_if< std::is_class< _Sseq >::value >::type seed (_Sseq &__q)
Seeds the initial state $x_0$ of the % subtract_with_carry_engine 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 result_type 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.

This is a model of a Generalized Fibonacci discrete random number generator, sometimes referred to as the SWC generator.

A discrete random number generator that produces pseudorandom numbers using: [ x_{i}leftarrow(x_{i - s} - x_{i - r} - carry_{i-1}) bmod m ]

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

Definition at line 659 of file random.h.

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.

Definition at line 662 of file random.h.

Constructor & Destructor Documentation

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 = default_seed) [inline], [explicit]

Constructs an explicitly seeded % subtract_with_carry_engine random number generator.

Definition at line 683 of file random.h.

template<typename _UIntType, size_t __w, size_t __s, size_t __r> template<typename _Sseq , typename = typename std::enable_if<!std::is_same<_Sseq, subtract_with_carry_engine>::value> ::type> 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.

Definition at line 696 of file random.h.

Member Function Documentation

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.

Definition at line 742 of file random.h.

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]

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

Definition at line 735 of file random.h.

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]

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

Definition at line 727 of file random.h.

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.

Definition at line 598 of file bits/random.tcc.

References std::dec(), std::fixed(), std::ios_base::flags(), std::left(), std::discard_block_engine< _RandomNumberEngine, __p, __r >::operator()(), std::__detail::operator>>(), and std::skipws().

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

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 = default_seed)

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_{lcg} = 0, and lcg(0) = value $, sets $ x_{-r} \dots x_{-1} $ to $ lcg(1) bmod m ots lcg(r) bmod m $ respectively. If $ x_{-1} = 0 $ set carry to 1, otherwise sets carry to 0.

Definition at line 543 of file bits/random.tcc.

Referenced by std::mersenne_twister_engine< uint_fast32_t, 32, 624, 397, 31, 0x9908b0dfUL, 11, 0xffffffffUL, 7, 0x9d2c5680UL, 15, 0xefc60000UL, 18, 1812433253UL >::discard().

template<typename _UIntType , size_t __w, size_t __s, size_t __r> template<typename _Sseq > std::enable_if< std::is_class< _Sseq >::value >::type 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.

Definition at line 572 of file bits/random.tcc.

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

Author

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Fri Sep 16 2016 libstdc++