[header][other] random (C++11)

*[header][other] random (C++11)

<random>

Random

This header introduces random number generation facilities.

This library allows to produce random numbers using combinations of generators and distributions:

• Generators: Objects that generate uniformly distributed numbers.
• Distributions: Objects that transform sequences of numbers generated by a generator into sequences of numbers that follow a specific random variable distribution, such as uniform, Normal or Binomial.

Distribution objects generate random numbers by means of their operator() member, which takes a generator object as argument:

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std::default_random_engine generator; std::uniform_int_distribution<int> distribution(1,6); int dice_roll = distribution(generator); // generates number in the range 1..6

For repeated uses, both can be bound together:

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auto dice = std::bind ( distribution, generator ); int wisdom = dice()+dice()+dice();

Except for random_device, all standard generators defined in the library are random number engines, which are a kind of generators that use a particular algorithm to generate series of pseudo-random numbers. These algorithms need a seed as a source of randomness, and this seed can either be a single value or an object with a very specific generate()member function (see seed_seq for more info). A typical source of randomness for trivial tasks is time, such as the information provided by time or system_clock::now (for a typical example, see uniform_int_distribution::operator()).

As an alternative, trivial random numbers can also be generated using cstdlib's functions rand and srand.

Generators

Pseudo-random number engines (templates)

Generators that use an algorithm to generate pseudo-random numbers based on an initial seed:

linear_congruential_engine

Linear congruential random number engine (class template )

mersenne_twister_engine

Mersenne twister random number engine (class template )

subtract_with_carry_engine

Subtract-with-carry random number engine (class template )

Engine adaptors

They adapt an engine, modifying the way numbers are generated with it:

discard_block_engine

Discard-block random number engine adaptor (class template )

independent_bits_engine

Independent-bits random number engine adaptor (class template )

shuffle_order_engine

Shuffle-order random number engine adaptor (class template )

Pseudo-random number engines (instantiations)

Particular instantiations of generator engines and adaptors:

default_random_engine

Default random engine (class )

minstd_rand

Minimal Standard minstd_rand generator (class )

minstd_rand0

Minimal Standard minstd_rand0 generator (class )

mt19937

Mersenne Twister 19937 generator (class )

mt19937_64

Mersene Twister 19937 generator (64 bit) (class )

ranlux24_base

Ranlux 24 base generator (class )

ranlux48_base

Ranlux 48 base generator (class )

ranlux24

Ranlux 24 generator (class )

ranlux48

Ranlux 48 generator (class )

knuth_b

Knuth-B generator (class )

Random number generators

Non-deterministic random number generator:

random_device

True random number generator (class )

Distributions

Uniform:

uniform_int_distribution

Uniform discrete distribution (class template )

uniform_real_distribution

Uniform real distribution (class template )

Related to Bernoulli (yes/no) trials:

bernoulli_distribution

Bernoulli distribution (class )

binomial_distribution

Binomial distribution (class template )

geometric_distribution

Geometric distribution (class template )

negative_binomial_distribution

Negative binomial distribution (class template )

Rate-based distributions:

poisson_distribution

Poisson distribution (class template )

exponential_distribution

Exponential distribution (class template )

gamma_distribution

Gamma distribution (class template )

weibull_distribution

Weibull distribution (class template )

extreme_value_distribution

Extreme Value distribution (class template )

Related to Normal distribution:

normal_distribution

Normal distribution (class template )

lognormal_distribution

Lognormal distribution (class template )

chi_squared_distribution

Chi-squared distribution (class template )

cauchy_distribution

Cauchy distribution (class template )

fisher_f_distribution

Fisher F-distribution (class template )

student_t_distribution

Student T-Distribution (class template )

Piecewise distributions:

discrete_distribution

Discrete distribution (class template )

piecewise_constant_distribution

Piecewise constant distribution (class template )

piecewise_linear_distribution

Piecewise linear distribution (class template )

Other

seed_seq

Seed sequence (class )

generate_canonical

Generate canonical numbers (function template )

내용 출처 : http://www.cplusplus.com/reference/random/