std::discard_block_engine

From cppreference.com

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros(C++20)
Language support library
Concepts library(C++20)
Diagnostics library
Memory management library
Metaprogramming library(C++11)
General utilities library
Containers library
Iterators library
Ranges library(C++20)
Algorithms library
Strings library
Text processing library
Numerics library
Date and time library
Input/output library
Filesystem library(C++17)
Concurrency support library(C++11)
Execution control library(C++26)
Technical specifications
Symbols index
External libraries

[edit]

Numerics library

Common mathematical functions

Mathematical special functions(C++17)

Mathematical constants(C++20)

Basic linear algebra algorithms(C++26)

Data-parallel types (SIMD)(C++26)

Floating-point environment(C++11)

Complex numbers

Numeric array (valarray)

Pseudo-random number generation

Bit manipulation(C++20)

Saturation arithmetic(C++26)

(C++17)

(C++17)

(C++20)

(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)

C-style checked integer arithmetic

ckd_add (C++26)
ckd_sub (C++26)

ckd_mul (C++26)

[edit]

Pseudo-random number generation

Uniform random bit generators

uniform_random_bit_generator

(C++20)

Random number engines

linear_congruential_engine

(C++11)

mersenne_twister_engine

(C++11)

subtract_with_carry_engine

(C++11)

philox_engine

(C++26)

Random number engine adaptors

discard_block_engine

(C++11)

independent_bits_engine

(C++11)

shuffle_order_engine

(C++11)

Predefined random number generators

Non-deterministic random numbers

(C++11)

(C++11)

(C++11)

Random number algorithms

ranges::generate_random

(C++26)

Random number 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)

[edit]

std::discard_block_engine

Member functions
discard_block_engine::discard_block_engine
discard_block_engine::seed
discard_block_engine::base
Generation
discard_block_engine::operator()
discard_block_engine::discard
Characteristics
discard_block_engine::min
discard_block_engine::max
Non-member functions
operator==operator!= (C++11)(C++11)(until C++20)
operator<<operator>> (C++11)(C++11)

[edit]

Defined in header`<random>`
template< class Engine, std::size_t P,std::size_t R >class discard_block_engine;		(since C++11)

discard_block_engine is a pseudo-random number engine adaptor that discards a certain amount of data produced by the base engine. From each block of sizeP generated by the base engine, the adaptor keeps onlyR numbers, discarding the rest.

[edit]Template parameters

Engine	-	the type of the wrapped engine.
P	-	the size of a block. Expected that\(\small{P>0}\)P > 0.
R	-	the number of used numbers per block. Expected that\(\small{0<R\le P}\)0 < R ≤ P.
Type requirements
- `Engine` must meet the requirements ofRandomNumberEngine.

[edit]Member types

Member type	Definition
`result_type`(C++11)	`Engine::result_type`

[edit]Member functions

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

[edit]Non-member functions

operator==operator!= (C++11)(C++11)(removed in C++20)	compares the internal states of the adaptors and underlying engines (function)[edit]
operator<<operator>> (C++11)	performs stream input and output on pseudo-random number engine adaptor (function)[edit]

[edit]Member constants

constexpr size_t block_size [static](C++11)	the size of the block,P (public static member constant)
constexpr size_t used_block [static](C++11)	the number of used numbers per block,R (public static member constant)