Trait rand::distributions::uniform::UniformSampler

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pub trait UniformSampler: Sized {
    type X;

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

    // Provided methods
    fn sample_single<R: Rng + ?Sized, B1, B2>(
        low: B1,
        high: B2,
        rng: &mut R
    ) -> Result<Self::X, Error>
       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
    ) -> Result<Self::X, Error>
       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§

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type X

The type sampled by this implementation.

Required Methods§

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fn new<B1, B2>(low: B1, high: B2) -> Result<Self, Error>where B1: SampleBorrow<Self::X> + Sized, B2: SampleBorrow<Self::X> + Sized,

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

Usually users should not call this directly but prefer to use Uniform::new.

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fn new_inclusive<B1, B2>(low: B1, high: B2) -> Result<Self, Error>where B1: SampleBorrow<Self::X> + Sized, B2: SampleBorrow<Self::X> + Sized,

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

Usually users should not call this directly but prefer to use Uniform::new_inclusive.

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

Sample a value.

Provided Methods§

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fn sample_single<R: Rng + ?Sized, B1, B2>( low: B1, high: B2, rng: &mut R ) -> Result<Self::X, Error>where B1: SampleBorrow<Self::X> + Sized, B2: SampleBorrow<Self::X> + Sized,

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).unwrap()
}
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fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>( low: B1, high: B2, rng: &mut R ) -> Result<Self::X, Error>where B1: SampleBorrow<Self::X> + Sized, B2: SampleBorrow<Self::X> + Sized,

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§