Struct xorshift::xoroshiro128::Xoroshiro128
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pub struct Xoroshiro128(_);
A random number generator that uses the xoroshiro128+ algorithm [1].
Description
Quoted from [1].
This is the successor to xorshift128+. It is the fastest full-period generator passing BigCrush without systematic failures, but due to the relatively short period it is acceptable only for applications with a mild amount of parallelism; otherwise, use a xorshift1024* generator.
Beside passing BigCrush, this generator passes the PractRand test suite up to (and included) 16TB, with the exception of binary rank tests, which fail due to the lowest bit being an LFSR; all other bits pass all tests. We suggest to use a sign test to extract a random Boolean value.
Note that the generator uses a simulated rotate operation, which most C compilers will turn into a single instruction. In Java, you can use Long.rotateLeft(). In languages that do not make low-level rotation instructions accessible xorshift128+ could be faster.
The state must be seeded so that it is not everywhere zero. If you have a 64-bit seed, we suggest to seed a splitmix64 generator and use its output to fill s.
[1]: Sebastiano Vigna, and David Blackman xoroshiro128+
Parallelism
The RngJump implementation is equivalent to 264 calls to next_u64(). Used to generate 264 non-overlapping subsequences for parallel computations.
Trait Implementations
impl Copy for Xoroshiro128
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impl Clone for Xoroshiro128
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fn clone(&self) -> Xoroshiro128
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0
Performs copy-assignment from source
. Read more
impl Rng for Xoroshiro128
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fn next_u32(&mut self) -> u32
Return the next random u32. Read more
fn next_u64(&mut self) -> u64
Return the next random u64. Read more
fn next_f32(&mut self) -> f32
Return the next random f32 selected from the half-open interval [0, 1)
. Read more
fn next_f64(&mut self) -> f64
Return the next random f64 selected from the half-open interval [0, 1)
. Read more
fn fill_bytes(&mut self, dest: &mut [u8])
Fill dest
with random data. Read more
fn gen<T>(&mut self) -> T where T: Rand
Return a random value of a Rand
type. Read more
fn gen_iter<T>(&'a mut self) -> Generator<'a, T, Self> where T: Rand
Return an iterator that will yield an infinite number of randomly generated items. Read more
fn gen_range<T>(&mut self, low: T, high: T) -> T where T: SampleRange + PartialOrd<T>
Generate a random value in the range [low
, high
). Read more
fn gen_weighted_bool(&mut self, n: u32) -> bool
Return a bool with a 1 in n chance of true Read more
fn gen_ascii_chars(&'a mut self) -> AsciiGenerator<'a, Self>
Return an iterator of random characters from the set A-Z,a-z,0-9. Read more
fn choose<T>(&mut self, values: &'a [T]) -> Option<&'a T>
Return a random element from values
. Read more
fn shuffle<T>(&mut self, values: &mut [T])
Shuffle a mutable slice in place. Read more
impl<'a> SeedableRng<&'a [u64]> for Xoroshiro128
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fn reseed(&mut self, seed: &'a [u64])
Reseed an RNG with the given seed. Read more
fn from_seed(seed: &'a [u64]) -> Xoroshiro128
Create a new RNG with the given seed. Read more
impl Rand for Xoroshiro128
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fn rand<R: Rng>(other: &mut R) -> Xoroshiro128
Generates a random instance of this type using the specified source of randomness. Read more