std::linear_congruential_engine

 

C++

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Named requirements

Feature test macros (C++20)

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Ranges library (C++20)

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Numerics library

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Filesystem library (C++17)

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Technical specifications

Symbols index

External libraries

 

Numerics library

Common mathematical functions

Mathematical special functions (C++17)

Mathematical constants (C++20)

Floating-point environment (C++11)

Complex numbers

Numeric arrays

Pseudo-random number generation

Factor operations

gcd (C++17)

lcm (C++17)

Interpolations

midpoint (C++20)

lerp (C++20)

Generic numeric operations

iota (C++11)

ranges::iota (C++23)

accumulate

inner_product

adjacent_difference

partial_sum

reduce (C++17)

transform_reduce (C++17)

inclusive_scan (C++17)

exclusive_scan (C++17)

transform_inclusive_scan (C++17)

transform_exclusive_scan (C++17)

Bit operations

bit_cast (C++20)

byteswap (C++23)

has_single_bit (C++20)

bit_ceil (C++20)

bit_floor (C++20)

bit_width (C++20)

rotl (C++20)

rotr (C++20)

countl_zero (C++20)

countl_one (C++20)

countr_zero (C++20)

countr_one (C++20)

popcount (C++20)

endian (C++20)

 

Pseudo-random number generation

Uniform random bit generators

uniform_random_bit_generator (C++20)

Engines and engine adaptors

linear_congruential_engine (C++11)

mersenne_twister_engine (C++11)

subtract_with_carry_engine (C++11)

discard_block_engine (C++11)

independent_bits_engine (C++11)

shuffle_order_engine (C++11)

Non-deterministic generator

random_device (C++11)

Distributions

Uniform distributions

uniform_int_distribution (C++11)

uniform_real_distribution (C++11)

generate_canonical (C++11)

Bernoulli distributions

bernoulli_distribution (C++11)

binomial_distribution (C++11)

negative_binomial_distribution (C++11)

geometric_distribution (C++11)

Poisson distributions

poisson_distribution (C++11)

exponential_distribution (C++11)

gamma_distribution (C++11)

weibull_distribution (C++11)

extreme_value_distribution (C++11)

Normal distributions

normal_distribution (C++11)

lognormal_distribution (C++11)

chi_squared_distribution (C++11)

cauchy_distribution (C++11)

fisher_f_distribution (C++11)

student_t_distribution (C++11)

Sampling distributions

discrete_distribution (C++11)

piecewise_constant_distribution (C++11)

piecewise_linear_distribution (C++11)

Seed Sequences

seed_seq (C++11)

C library

rand

srand

RAND_MAX

 

std::linear_congruential_engine

Member functions

linear_congruential_engine::linear_congruential_engine (C++11)

linear_congruential_engine::seed (C++11)

Generation

linear_congruential_engine::operator() (C++11)

linear_congruential_engine::discard (C++11)

Characteristics

linear_congruential_engine::min (C++11)

linear_congruential_engine::max (C++11)

Non-member functions

operator==operator!= (C++11)(C++11)(until C++20)

operator<<operator>> (C++11)(C++11)

 

Defined in header <random>
template<     class UIntType,     UIntType a,     UIntType c,     UIntType m > class linear_congruential_engine;		(since C++11)

linear_congruential_engine is a random number engine based on Linear congruential generator (LCG). A LCG has a state that consists of a single integer.

The transition algorithm of the LCG function is \(\small{x_{i+1}\leftarrow(a x_i + c)\mod m}\)x
i+1 ← (ax
i+c) mod m.

The following typedefs define the random number engine with two commonly used parameter sets:

Defined in header <random>
Type	Definition
minstd_rand0(C++11)	std::linear_congruential_engine<std::uint_fast32_t, 16807, 0, 2147483647> Discovered in 1969 by Lewis, Goodman and Miller, adopted as "Minimal standard" in 1988 by Park and Miller
minstd_rand(C++11)	std::linear_congruential_engine<std::uint_fast32_t, 48271, 0, 2147483647> Newer "Minimum standard", recommended by Park, Miller, and Stockmeyer in 1993

Template parameters

UIntType	-	The result type generated by the generator. The effect is undefined if this is not one of unsigned short, unsigned int, unsigned long, or unsigned long long.
a	-	the multiplier term
c	-	the increment term
m	-	the modulus term

Member types

Member type	Definition
result_type(C++11)	The integral type generated by the engine. Results are undefined if this is not an unsigned integral type.

Member functions

Construction and Seeding
(constructor) (C++11)	constructs the engine (public member function)
seed (C++11)	sets the current state of the engine (public member function)
Generation
operator() (C++11)	advances the engine's state and returns the generated value (public member function)
discard (C++11)	advances the engine's state by a specified amount (public member function)
Characteristics
min [static] (C++11)	gets the smallest possible value in the output range (public static member function)
max [static] (C++11)	gets the largest possible value in the output range (public static member function)

Non-member functions

operator==operator!= (C++11)(C++11)(removed in C++20)	compares the internal states of two pseudo-random number engines (function)
operator<<operator>> (C++11)	performs stream input and output on pseudo-random number engine (function template)

Member constants

constexpr UIntType multiplier [static] (C++11)	the multiplier term (a). (public static member constant)
constexpr UIntType increment [static] (C++11)	the increment term (c). (public static member constant)
constexpr UIntType modulus [static] (C++11)	the modulus term (m). (public static member constant)
constexpr UIntType default_seed [static] (C++11)	the default seed (1). (public static member constant)