[−][src]Struct peroxide::macros::r_macro::SmallRng
An RNG recommended when small state, cheap initialization and good
performance are required. The PRNG algorithm in SmallRng
is chosen to be
efficient on the current platform, without consideration for cryptography
or security. The size of its state is much smaller than for StdRng
.
Reproducibility of output from this generator is however not required, thus future library versions may use a different internal generator with different output. Further, this generator may not be portable and can produce different output depending on the architecture. If you require reproducible output, use a named RNG. Refer to The Book.
The current algorithm is [Pcg64Mcg
][rand_pcg::Pcg64Mcg] on 64-bit platforms with Rust version
1.26 and later, or [Pcg32
][rand_pcg::Pcg32] otherwise. Both are found in
the rand_pcg crate.
Examples
Initializing SmallRng
with a random seed can be done using FromEntropy
:
use rand::FromEntropy; use rand::rngs::SmallRng; // Create small, cheap to initialize and fast RNG with a random seed. // The randomness is supplied by the operating system. let mut small_rng = SmallRng::from_entropy();
When initializing a lot of SmallRng
's, using thread_rng
can be more
efficient:
use std::iter; use rand::{SeedableRng, thread_rng}; use rand::rngs::SmallRng; // Create a big, expensive to initialize and slower, but unpredictable RNG. // This is cached and done only once per thread. let mut thread_rng = thread_rng(); // Create small, cheap to initialize and fast RNGs with random seeds. // One can generally assume this won't fail. let rngs: Vec<SmallRng> = iter::repeat(()) .map(|()| SmallRng::from_rng(&mut thread_rng).unwrap()) .take(10) .collect();
Trait Implementations
impl Debug for SmallRng
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impl Clone for SmallRng
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fn clone(&self) -> SmallRng
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default fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl SeedableRng for SmallRng
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type Seed = <Mcg128Xsl64 as SeedableRng>::Seed
Seed type, which is restricted to types mutably-dereferencable as u8
arrays (we recommend [u8; N]
for some N
). Read more
fn from_seed(seed: <SmallRng as SeedableRng>::Seed) -> SmallRng
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fn from_rng<R>(rng: R) -> Result<SmallRng, Error> where
R: RngCore,
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R: RngCore,
default fn seed_from_u64(state: u64) -> Self
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Create a new PRNG using a u64
seed. Read more
impl RngCore for SmallRng
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Auto Trait Implementations
Blanket Implementations
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
impl<T> From for T
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impl<T, U> Into for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T> Borrow for T where
T: ?Sized,
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T: ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> BorrowMut for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T, U> TryInto for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<R> Rng for R where
R: RngCore + ?Sized,
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R: RngCore + ?Sized,
default fn gen<T>(&mut self) -> T where
Standard: Distribution<T>,
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Standard: Distribution<T>,
Return a random value supporting the [Standard
] distribution. Read more
default fn gen_range<T, B1, B2>(&mut self, low: B1, high: B2) -> T where
B1: SampleBorrow<T>,
B2: SampleBorrow<T>,
T: SampleUniform,
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B1: SampleBorrow<T>,
B2: SampleBorrow<T>,
T: SampleUniform,
Generate a random value in the range [low
, high
), i.e. inclusive of low
and exclusive of high
. Read more
default fn sample<T, D>(&mut self, distr: D) -> T where
D: Distribution<T>,
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D: Distribution<T>,
Sample a new value, using the given distribution. Read more
default fn sample_iter<T, D>(
&'a mut self,
distr: &'a D
) -> DistIter<'a, D, Self, T> where
D: Distribution<T>,
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&'a mut self,
distr: &'a D
) -> DistIter<'a, D, Self, T> where
D: Distribution<T>,
Create an iterator that generates values using the given distribution. Read more
default fn fill<T>(&mut self, dest: &mut T) where
T: AsByteSliceMut + ?Sized,
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T: AsByteSliceMut + ?Sized,
Fill dest
entirely with random bytes (uniform value distribution), where dest
is any type supporting [AsByteSliceMut
], namely slices and arrays over primitive integer types (i8
, i16
, u32
, etc.). Read more
default fn try_fill<T>(&mut self, dest: &mut T) -> Result<(), Error> where
T: AsByteSliceMut + ?Sized,
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T: AsByteSliceMut + ?Sized,
Fill dest
entirely with random bytes (uniform value distribution), where dest
is any type supporting [AsByteSliceMut
], namely slices and arrays over primitive integer types (i8
, i16
, u32
, etc.). Read more
default fn gen_bool(&mut self, p: f64) -> bool
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Return a bool with a probability p
of being true. Read more
default fn gen_ratio(&mut self, numerator: u32, denominator: u32) -> bool
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Return a bool with a probability of numerator/denominator
of being true. I.e. gen_ratio(2, 3)
has chance of 2 in 3, or about 67%, of returning true. If numerator == denominator
, then the returned value is guaranteed to be true
. If numerator == 0
, then the returned value is guaranteed to be false
. Read more
default fn choose<T>(&mut self, values: &'a [T]) -> Option<&'a T>
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use SliceRandom::choose instead
Return a random element from values
. Read more
default fn choose_mut<T>(&mut self, values: &'a mut [T]) -> Option<&'a mut T>
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use SliceRandom::choose_mut instead
Return a mutable pointer to a random element from values
. Read more
default fn shuffle<T>(&mut self, values: &mut [T])
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use SliceRandom::shuffle instead
Shuffle a mutable slice in place. Read more
impl<R> FromEntropy for R where
R: SeedableRng,
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R: SeedableRng,