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std::subtract_with_carry_engine< _UIntType, __w, __s, __r > Class Template Reference
Numerics » Random Number Generation » Random Number Generators

Public Types

typedef _UIntType result_type
 

Public Member Functions

 subtract_with_carry_engine (result_type __sd=default_seed)
 
template<typename _Sseq , typename = typename std::enable_if<!std::is_same<_Sseq, subtract_with_carry_engine>::value> ::type>
 subtract_with_carry_engine (_Sseq &__q)
 
void discard (unsigned long long __z)
 
result_type operator() ()
 
void seed (result_type __sd=default_seed)
 
template<typename _Sseq >
std::enable_if< std::is_class< _Sseq >::value >::type seed (_Sseq &__q)
 

Static Public Member Functions

static constexpr result_type max ()
 
static constexpr result_type min ()
 

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)
 
bool operator== (const subtract_with_carry_engine &__lhs, const subtract_with_carry_engine &__rhs)
 
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)
 

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)
inlineexplicit

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)
inlineexplicit

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

Parameters
__qthe 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 ( )
inlinestatic

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 ( )
inlinestatic

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 \dots 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< _UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f >::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()().

Friends And Related Function Documentation

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
__osAn output stream.
__xA % subtract_with_carry_engine random number generator engine.
Returns
The output stream with the state of __x inserted or in an error state.
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
__lhsA % subtract_with_carry_engine random number generator object.
__rhsAnother % subtract_with_carry_engine random number generator object.
Returns
true if the infinite sequences of generated values would be equal, false otherwise.

Definition at line 767 of file random.h.

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
__isAn input stream.
__xA % subtract_with_carry_engine random number generator engine.
Returns
The input stream with the state of __x extracted or in an error state.
The documentation for this class was generated from the following files: