pub struct Standard;Expand description
A generic random value distribution, implemented for many primitive types. Usually generates values with a numerically uniform distribution, and with a range appropriate to the type.
§Provided implementations
Assuming the provided Rng is well-behaved, these implementations
generate values with the following ranges and distributions:
- Integers (
i32,u32,isize,usize, etc.): Uniformly distributed over all values of the type. char: Uniformly distributed over all Unicode scalar values, i.e. all code points in the range0...0x10_FFFF, except for the range0xD800...0xDFFF(the surrogate code points). This includes unassigned/reserved code points.bool: Generatesfalseortrue, each with probability 0.5.- Floating point types (
f32andf64): Uniformly distributed in the half-open range[0, 1). See notes below. - Wrapping integers (
Wrapping<T>), besides the type identical to their normal integer variants.
The Standard distribution also supports generation of the following
compound types where all component types are supported:
- Tuples (up to 12 elements): each element is generated sequentially.
- Arrays (up to 32 elements): each element is generated sequentially;
see also
Rng::fillwhich supports arbitrary array length for integer and float types and tends to be faster foru32and smaller types. When usingrustc≥ 1.51, enable themin_const_genfeature to support arrays larger than 32 elements. Note thatRng::fillandStandard’s array support are not equivalent: the former is optimised for integer types (using fewer RNG calls for element types smaller than the RNG word size), while the latter supports any element type supported byStandard. Option<T>first generates abool, and if true generates and returnsSome(value)wherevalue: T, otherwise returningNone.
§Custom implementations
The Standard distribution may be implemented for user types as follows:
use rand::Rng;
use rand::distributions::{Distribution, Standard};
struct MyF32 {
x: f32,
}
impl Distribution<MyF32> for Standard {
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> MyF32 {
MyF32 { x: rng.gen() }
}
}§Example usage
use rand::prelude::*;
use rand::distributions::Standard;
let val: f32 = StdRng::from_entropy().sample(Standard);
println!("f32 from [0, 1): {}", val);§Floating point implementation
The floating point implementations for Standard generate a random value in
the half-open interval [0, 1), i.e. including 0 but not 1.
All values that can be generated are of the form n * ε/2. For f32
the 24 most significant random bits of a u32 are used and for f64 the
53 most significant bits of a u64 are used. The conversion uses the
multiplicative method: (rng.gen::<$uty>() >> N) as $ty * (ε/2).
See also: Open01 which samples from (0, 1), OpenClosed01 which
samples from (0, 1] and Rng::gen_range(0..1) which also samples from
[0, 1). Note that Open01 uses transmute-based methods which yield 1 bit
less precision but may perform faster on some architectures (on modern Intel
CPUs all methods have approximately equal performance).
Trait Implementations§
Source§impl DistString for Standard
Note: the String is potentially left with excess capacity; optionally the
user may call string.shrink_to_fit() afterwards.
impl DistString for Standard
Note: the String is potentially left with excess capacity; optionally the
user may call string.shrink_to_fit() afterwards.
Source§impl<T> Distribution<[T; 32]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 32]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 31]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 31]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 30]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 30]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 29]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 29]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 28]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 28]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 27]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 27]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 26]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 26]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 25]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 25]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 24]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 24]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 23]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 23]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 22]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 22]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 21]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 21]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 20]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 20]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 19]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 19]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 18]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 18]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 17]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 17]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 16]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 16]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 15]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 15]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 14]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 14]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 13]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 13]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 12]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 12]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 11]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 11]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 10]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 10]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 9]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 9]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 8]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 8]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 7]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 7]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 6]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 6]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 5]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 5]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 4]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 4]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 3]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 3]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 2]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 2]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 1]> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<[T; 1]> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<[T; 0]> for Standard
impl<T> Distribution<[T; 0]> for Standard
Source§impl Distribution<()> for Standard
impl Distribution<()> for Standard
Source§impl<A> Distribution<(A,)> for Standardwhere
Standard: Distribution<A>,
impl<A> Distribution<(A,)> for Standardwhere
Standard: Distribution<A>,
Source§impl<A, B> Distribution<(A, B)> for Standard
impl<A, B> Distribution<(A, B)> for Standard
Source§impl<A, B, C> Distribution<(A, B, C)> for Standard
impl<A, B, C> Distribution<(A, B, C)> for Standard
Source§impl<A, B, C, D> Distribution<(A, B, C, D)> for Standard
impl<A, B, C, D> Distribution<(A, B, C, D)> for Standard
Source§impl<A, B, C, D, E> Distribution<(A, B, C, D, E)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E>,
impl<A, B, C, D, E> Distribution<(A, B, C, D, E)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E>,
Source§impl<A, B, C, D, E, F> Distribution<(A, B, C, D, E, F)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F>,
impl<A, B, C, D, E, F> Distribution<(A, B, C, D, E, F)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F>,
Source§impl<A, B, C, D, E, F, G> Distribution<(A, B, C, D, E, F, G)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G>,
impl<A, B, C, D, E, F, G> Distribution<(A, B, C, D, E, F, G)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G>,
Source§impl<A, B, C, D, E, F, G, H> Distribution<(A, B, C, D, E, F, G, H)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H>,
impl<A, B, C, D, E, F, G, H> Distribution<(A, B, C, D, E, F, G, H)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H>,
Source§fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H)
fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H)
T, using rng as the source of randomness.Source§impl<A, B, C, D, E, F, G, H, I> Distribution<(A, B, C, D, E, F, G, H, I)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I>,
impl<A, B, C, D, E, F, G, H, I> Distribution<(A, B, C, D, E, F, G, H, I)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I>,
Source§fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I)
fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I)
T, using rng as the source of randomness.Source§impl<A, B, C, D, E, F, G, H, I, J> Distribution<(A, B, C, D, E, F, G, H, I, J)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I> + Distribution<J>,
impl<A, B, C, D, E, F, G, H, I, J> Distribution<(A, B, C, D, E, F, G, H, I, J)> for Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I> + Distribution<J>,
Source§fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I, J)
fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I, J)
T, using rng as the source of randomness.Source§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 Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I> + Distribution<J> + Distribution<K>,
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 Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I> + Distribution<J> + Distribution<K>,
Source§fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I, J, K)
fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I, J, K)
T, using rng as the source of randomness.Source§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 Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I> + Distribution<J> + Distribution<K> + Distribution<L>,
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 Standardwhere
Standard: Distribution<A> + Distribution<B> + Distribution<C> + Distribution<D> + Distribution<E> + Distribution<F> + Distribution<G> + Distribution<H> + Distribution<I> + Distribution<J> + Distribution<K> + Distribution<L>,
Source§fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I, J, K, L)
fn sample<R>(&self, _rng: &mut R) -> (A, B, C, D, E, F, G, H, I, J, K, L)
T, using rng as the source of randomness.Source§impl Distribution<NonZero<u128>> for Standard
impl Distribution<NonZero<u128>> for Standard
Source§impl Distribution<NonZero<u16>> for Standard
impl Distribution<NonZero<u16>> for Standard
Source§impl Distribution<NonZero<u32>> for Standard
impl Distribution<NonZero<u32>> for Standard
Source§impl Distribution<NonZero<u64>> for Standard
impl Distribution<NonZero<u64>> for Standard
Source§impl Distribution<NonZero<u8>> for Standard
impl Distribution<NonZero<u8>> for Standard
Source§impl Distribution<NonZero<usize>> for Standard
impl Distribution<NonZero<usize>> for Standard
Source§impl<T> Distribution<Option<T>> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<Option<T>> for Standardwhere
Standard: Distribution<T>,
Source§impl<T> Distribution<Wrapping<T>> for Standardwhere
Standard: Distribution<T>,
impl<T> Distribution<Wrapping<T>> for Standardwhere
Standard: Distribution<T>,
Source§impl Distribution<bool> for Standard
impl Distribution<bool> for Standard
Source§impl Distribution<char> for Standard
impl Distribution<char> for Standard
Source§impl Distribution<f32> for Standard
impl Distribution<f32> for Standard
Source§impl Distribution<f64> for Standard
impl Distribution<f64> for Standard
Source§impl Distribution<i128> for Standard
impl Distribution<i128> for Standard
Source§impl Distribution<i16> for Standard
impl Distribution<i16> for Standard
Source§impl Distribution<i32> for Standard
impl Distribution<i32> for Standard
Source§impl Distribution<i64> for Standard
impl Distribution<i64> for Standard
Source§impl Distribution<i8> for Standard
impl Distribution<i8> for Standard
Source§impl Distribution<isize> for Standard
impl Distribution<isize> for Standard
Source§impl Distribution<u128> for Standard
impl Distribution<u128> for Standard
Source§impl Distribution<u16> for Standard
impl Distribution<u16> for Standard
Source§impl Distribution<u32> for Standard
impl Distribution<u32> for Standard
Source§impl Distribution<u64> for Standard
impl Distribution<u64> for Standard
Source§impl Distribution<u8> for Standard
impl Distribution<u8> for Standard
Source§impl Distribution<usize> for Standard
impl Distribution<usize> for Standard
impl Copy for Standard
Auto Trait Implementations§
impl Freeze for Standard
impl RefUnwindSafe for Standard
impl Send for Standard
impl Sync for Standard
impl Unpin for Standard
impl UnwindSafe for Standard
Blanket Implementations§
Source§impl<T> AsyncTaskResult for T
impl<T> AsyncTaskResult for T
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
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T: Any,
impl<T> Downcast for Twhere
T: Any,
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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>
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further downcast into Rc<ConcreteType> where ConcreteType implements Trait.Source§fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
&Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot
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Source§fn into_either(self, into_left: bool) -> Either<Self, Self> ⓘ
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self as &dyn AnySource§impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
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