Trait rand::distributions::uniform::UniformSampler

source · [−]
pub trait UniformSampler: Sized {
    type X;

    fn new<B1, B2>(low: B1, high: B2) -> Self
    where
        B1: SampleBorrow<Self::X> + Sized,
        B2: SampleBorrow<Self::X> + Sized;
    fn new_inclusive<B1, B2>(low: B1, high: B2) -> Self
    where
        B1: SampleBorrow<Self::X> + Sized,
        B2: SampleBorrow<Self::X> + Sized;
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X;

    fn sample_single<R: Rng + ?Sized, B1, B2>(
        low: B1,
        high: B2,
        rng: &mut R
    ) -> Self::X
    where
        B1: SampleBorrow<Self::X> + Sized,
        B2: SampleBorrow<Self::X> + Sized,
    { ... }
    fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
        low: B1,
        high: B2,
        rng: &mut R
    ) -> Self::X
    where
        B1: SampleBorrow<Self::X> + Sized,
        B2: SampleBorrow<Self::X> + Sized,
    { ... }
}
Expand description

Helper trait handling actual uniform sampling.

See the module documentation on how to implement Uniform range sampling for a custom type.

Implementation of sample_single is optional, and is only useful when the implementation can be faster than Self::new(low, high).sample(rng).

Required Associated Types

The type sampled by this implementation.

Required Methods

Construct self, with inclusive lower bound and exclusive upper bound [low, high).

Usually users should not call this directly but instead use Uniform::new, which asserts that low < high before calling this.

Construct self, with inclusive bounds [low, high].

Usually users should not call this directly but instead use Uniform::new_inclusive, which asserts that low <= high before calling this.

Sample a value.

Provided Methods

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound [low, high).

By default this is implemented using UniformSampler::new(low, high).sample(rng). However, for some types more optimal implementations for single usage may be provided via this method (which is the case for integers and floats). Results may not be identical.

Note that to use this method in a generic context, the type needs to be retrieved via SampleUniform::Sampler as follows:

use rand::{thread_rng, distributions::uniform::{SampleUniform, UniformSampler}};
fn sample_from_range<T: SampleUniform>(lb: T, ub: T) -> T {
    let mut rng = thread_rng();
    <T as SampleUniform>::Sampler::sample_single(lb, ub, &mut rng)
}

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound [low, high].

By default this is implemented using UniformSampler::new_inclusive(low, high).sample(rng). However, for some types more optimal implementations for single usage may be provided via this method. Results may not be identical.

Implementors