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ContextRandomExt

ixa::random

Trait ContextRandomExt 

Source 
pub trait ContextRandomExt: ContextBase {
    // Provided methods
    fn init_random(&mut self, base_seed: u64) { ... }
    fn sample<R: RngId + 'static, T>(
        &self,
        _rng_type: R,
        sampler: impl FnOnce(&mut R::RngType) -> T,
    ) -> T { ... }
    fn debug_rng_state<R: RngId + 'static>(&self, _rng_id: R) -> u64
       where R::RngType: Clone + Rng { ... }
    fn sample_distr<R: RngId + 'static, T>(
        &self,
        _rng_type: R,
        distribution: impl Distribution<T>,
    ) -> T
       where R::RngType: Rng { ... }
    fn sample_range<R: RngId + 'static, S, T>(&self, rng_id: R, range: S) -> T
       where R::RngType: Rng,
             S: SampleRange<T>,
             T: SampleUniform { ... }
    fn sample_bool<R: RngId + 'static>(
        &self,
        rng_id: R,
        p: impl Into<f64>,
    ) -> bool
       where R::RngType: Rng { ... }
    fn sample_weighted<R: RngId + 'static, T>(
        &self,
        _rng_id: R,
        weights: &[T],
    ) -> usize
       where R::RngType: Rng,
             T: Clone + Default + SampleUniform + for<'a> AddAssign<&'a T> + PartialOrd + Weight { ... }
}

Provided Methods§

Source

fn init_random(&mut self, base_seed: u64)

Initializes the RngPlugin data container to store rngs as well as a base seed. Note that rngs are created lazily when get_rng is called.

§Panics

Panics if RNG state is currently borrowed by an active sampler callback.

Source

fn sample<R: RngId + 'static, T>( &self, _rng_type: R, sampler: impl FnOnce(&mut R::RngType) -> T, ) -> T

Gets a random sample from the random number generator associated with the given RngId by applying the specified sampler function. The RNG is created lazily from the current base seed on first use. The base seed is 0 unless it has been set with ContextRandomExt::init_random.

§Panics

Panics if RNG state is already borrowed, such as when a sampler callback recursively samples from the same context.

Source

fn debug_rng_state<R: RngId + 'static>(&self, _rng_id: R) -> u64
where R::RngType: Clone + Rng,

Returns a deterministic debug fingerprint for the current position of the random number generator associated with the given RngId.

This clones the current generator and hashes a small number of draws from the clone, so it does not advance the generator used by sampling. The returned value is intended only for comparing checkpoints across runs of the same code and dependency versions. It is not a serialization format, and it does not guarantee reproducibility across RNG algorithm or version changes.

Source

fn sample_distr<R: RngId + 'static, T>( &self, _rng_type: R, distribution: impl Distribution<T>, ) -> T
where R::RngType: Rng,

Gets a random sample from the specified distribution using a random number generator associated with the given RngId. The RNG is created lazily from the current base seed on first use. The base seed is 0 unless it has been set with ContextRandomExt::init_random.

§Panics

Panics if RNG state is already borrowed by an active sampler callback.

Source

fn sample_range<R: RngId + 'static, S, T>(&self, rng_id: R, range: S) -> T
where R::RngType: Rng, S: SampleRange<T>, T: SampleUniform,

Gets a random sample within the range provided by range using the generator associated with the given RngId.

§Panics

Panics if RNG state is already borrowed or if range is invalid for the sampled type.

Source

fn sample_bool<R: RngId + 'static>(&self, rng_id: R, p: impl Into<f64>) -> bool
where R::RngType: Rng,

Gets a random boolean value which is true with probability p using the generator associated with the given RngId. The supplied probability is converted to f64 before sampling.

use ixa::{define_rng, Context, ContextRandomExt};

define_rng!(ExampleRng);

struct Probability(f64);

impl From<Probability> for f64 {
    fn from(probability: Probability) -> Self {
        probability.0
    }
}

let mut context = Context::new();
context.init_random(42);
assert!(context.sample_bool(ExampleRng, Probability(1.0)));
§Panics

Panics if RNG state is already borrowed or if the provided probability p is not in the interval 0.0..=1.0.

Source

fn sample_weighted<R: RngId + 'static, T>( &self, _rng_id: R, weights: &[T], ) -> usize
where R::RngType: Rng, T: Clone + Default + SampleUniform + for<'a> AddAssign<&'a T> + PartialOrd + Weight,

Draws a random entry out of the list provided in weights with the given weights using the generator associated with the given RngId. The weights must be nonnegative numbers with at least one positive weight.

§Panics

Panics if RNG state is already borrowed or if weights is not a list of nonnegative numbers with at least one positive weight.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§