Trait rand::distributions::Distribution

pub trait Distribution<T> {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> T;

    fn sample_iter<R>(self, rng: R) -> DistIter<Self, R, T>
    where
        R: Rng,
        Self: Sized,
    { ... }
}

Types (distributions) that can be used to create a random instance of T.

It is possible to sample from a distribution through both the Distribution and Rng traits, via distr.sample(&mut rng) and rng.sample(distr). They also both offer the sample_iter method, which produces an iterator that samples from the distribution.

All implementations are expected to be immutable; this has the significant advantage of not needing to consider thread safety, and for most distributions efficient state-less sampling algorithms are available.

Implementations are typically expected to be portable with reproducible results when used with a PRNG with fixed seed; see the portability chapter of The Rust Rand Book. In some cases this does not apply, e.g. the usize type requires different sampling on 32-bit and 64-bit machines.

Required methods

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> T

Generate a random value of T, using rng as the source of randomness.

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Provided methods

fn sample_iter<R>(self, rng: R) -> DistIter<Self, R, T> where
    R: Rng,
    Self: Sized, 

Create an iterator that generates random values of T, using rng as the source of randomness.

Note that this function takes self by value. This works since Distribution<T> is impl’d for &D where D: Distribution<T>, however borrowing is not automatic hence distr.sample_iter(...) may need to be replaced with (&distr).sample_iter(...) to borrow or (&*distr).sample_iter(...) to reborrow an existing reference.

Example

use rand::thread_rng;
use rand::distributions::{Distribution, Alphanumeric, Uniform, Standard};

let mut rng = thread_rng();

// Vec of 16 x f32:
let v: Vec<f32> = Standard.sample_iter(&mut rng).take(16).collect();

// String:
let s: String = Alphanumeric
    .sample_iter(&mut rng)
    .take(7)
    .map(char::from)
    .collect();

// Dice-rolling:
let die_range = Uniform::new_inclusive(1, 6);
let mut roll_die = die_range.sample_iter(&mut rng);
while roll_die.next().unwrap() != 6 {
    println!("Not a 6; rolling again!");
}

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Implementations on Foreign Types

impl<'a, T, D: Distribution<T>> Distribution<T> for &'a D

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> T

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Implementors

impl Distribution<bool> for Bernoulli

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> bool

impl Distribution<bool> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> bool

impl Distribution<char> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> char

impl Distribution<f32> for Open01

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f32

impl Distribution<f32> for OpenClosed01

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f32

impl Distribution<f32> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f32

impl Distribution<f64> for Open01

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64

impl Distribution<f64> for OpenClosed01

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64

impl Distribution<f64> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f64

impl Distribution<i8> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i8

impl Distribution<i16> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i16

impl Distribution<i32> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i32

impl Distribution<i64> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i64

impl Distribution<i128> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i128

impl Distribution<isize> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> isize

impl Distribution<u8> for Alphanumeric

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u8

impl Distribution<u8> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u8

impl Distribution<u16> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u16

impl Distribution<u32> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u32

impl Distribution<u64> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u64

impl Distribution<u128> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u128

impl Distribution<()> for Standard

fn sample<R: Rng + ?Sized>(&self, _: &mut R)

impl Distribution<usize> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> usize

impl Distribution<NonZeroU8> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> NonZeroU8

impl Distribution<NonZeroU16> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> NonZeroU16

impl Distribution<NonZeroU32> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> NonZeroU32

impl Distribution<NonZeroU64> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> NonZeroU64

impl Distribution<NonZeroU128> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> NonZeroU128

impl Distribution<NonZeroUsize> for Standard

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> NonZeroUsize

impl<A> Distribution<(A,)> for Standard where
    Standard: Distribution<A>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A,)

impl<A, B> Distribution<(A, B)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B)

impl<A, B, C> Distribution<(A, B, C)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B, C)

impl<A, B, C, D> Distribution<(A, B, C, D)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B, C, D)

impl<A, B, C, D, E> Distribution<(A, B, C, D, E)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B, C, D, E)

impl<A, B, C, D, E, F> Distribution<(A, B, C, D, E, F)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>,
    Standard: Distribution<F>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B, C, D, E, F)

impl<A, B, C, D, E, F, G> Distribution<(A, B, C, D, E, F, G)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>,
    Standard: Distribution<F>,
    Standard: Distribution<G>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G)

impl<A, B, C, D, E, F, G, H> Distribution<(A, B, C, D, E, F, G, H)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>,
    Standard: Distribution<F>,
    Standard: Distribution<G>,
    Standard: Distribution<H>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H)

impl<A, B, C, D, E, F, G, H, I> Distribution<(A, B, C, D, E, F, G, H, I)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>,
    Standard: Distribution<F>,
    Standard: Distribution<G>,
    Standard: Distribution<H>,
    Standard: Distribution<I>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I)

impl<A, B, C, D, E, F, G, H, I, J> Distribution<(A, B, C, D, E, F, G, H, I, J)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>,
    Standard: Distribution<F>,
    Standard: Distribution<G>,
    Standard: Distribution<H>,
    Standard: Distribution<I>,
    Standard: Distribution<J>, 

fn sample<R: Rng + ?Sized>(
    &self,
    _rng: &mut R
) -> (A, B, C, D, E, F, G, H, I, J)

impl<A, B, C, D, E, F, G, H, I, J, K> Distribution<(A, B, C, D, E, F, G, H, I, J, K)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>,
    Standard: Distribution<F>,
    Standard: Distribution<G>,
    Standard: Distribution<H>,
    Standard: Distribution<I>,
    Standard: Distribution<J>,
    Standard: Distribution<K>, 

fn sample<R: Rng + ?Sized>(
    &self,
    _rng: &mut R
) -> (A, B, C, D, E, F, G, H, I, J, K)

impl<A, B, C, D, E, F, G, H, I, J, K, L> Distribution<(A, B, C, D, E, F, G, H, I, J, K, L)> for Standard where
    Standard: Distribution<A>,
    Standard: Distribution<B>,
    Standard: Distribution<C>,
    Standard: Distribution<D>,
    Standard: Distribution<E>,
    Standard: Distribution<F>,
    Standard: Distribution<G>,
    Standard: Distribution<H>,
    Standard: Distribution<I>,
    Standard: Distribution<J>,
    Standard: Distribution<K>,
    Standard: Distribution<L>, 

fn sample<R: Rng + ?Sized>(
    &self,
    _rng: &mut R
) -> (A, B, C, D, E, F, G, H, I, J, K, L)

impl<T> Distribution<Option<T>> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Option<T>

impl<T> Distribution<[T; 0]> for Standard

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 0]

impl<T> Distribution<[T; 1]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 1]

impl<T> Distribution<[T; 2]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 2]

impl<T> Distribution<[T; 3]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 3]

impl<T> Distribution<[T; 4]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 4]

impl<T> Distribution<[T; 5]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 5]

impl<T> Distribution<[T; 6]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 6]

impl<T> Distribution<[T; 7]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 7]

impl<T> Distribution<[T; 8]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 8]

impl<T> Distribution<[T; 9]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 9]

impl<T> Distribution<[T; 10]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 10]

impl<T> Distribution<[T; 11]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 11]

impl<T> Distribution<[T; 12]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 12]

impl<T> Distribution<[T; 13]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 13]

impl<T> Distribution<[T; 14]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 14]

impl<T> Distribution<[T; 15]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 15]

impl<T> Distribution<[T; 16]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 16]

impl<T> Distribution<[T; 17]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 17]

impl<T> Distribution<[T; 18]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 18]

impl<T> Distribution<[T; 19]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 19]

impl<T> Distribution<[T; 20]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 20]

impl<T> Distribution<[T; 21]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 21]

impl<T> Distribution<[T; 22]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 22]

impl<T> Distribution<[T; 23]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 23]

impl<T> Distribution<[T; 24]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 24]

impl<T> Distribution<[T; 25]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 25]

impl<T> Distribution<[T; 26]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 26]

impl<T> Distribution<[T; 27]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 27]

impl<T> Distribution<[T; 28]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 28]

impl<T> Distribution<[T; 29]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 29]

impl<T> Distribution<[T; 30]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 30]

impl<T> Distribution<[T; 31]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 31]

impl<T> Distribution<[T; 32]> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, _rng: &mut R) -> [T; 32]

impl<T> Distribution<Wrapping<T>> for Standard where
    Standard: Distribution<T>, 

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Wrapping<T>

impl<X> Distribution<usize> for WeightedIndex<X> where
    X: SampleUniform + PartialOrd, 

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> usize

impl<X: SampleUniform> Distribution<X> for Uniform<X>

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> X

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