Struct SplitMix64 

pub struct SplitMix64 { /* private fields */ }

🎲 SplitMix64 pseudo-random number generator.

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^{📍 num/prob/rand}

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A small 64-bit-state generator useful for seed expansion, simple streams, and diffusing weak seed material.

This is not a cryptographic generator.

Implementations

impl SplitMix64

pub const GOLDEN_GAMMA: u64 = 0x9E37_79B9_7F4A_7C15

Weyl increment derived from the 64-bit fractional golden ratio.

pub const MIX_A: u64 = 0xBF58_476D_1CE4_E5B9

First SplitMix64 avalanche multiplier.

pub const MIX_B: u64 = 0x94D0_49BB_1331_11EB

Second SplitMix64 avalanche multiplier.

pub const fn new(seed: u64) -> Self

Creates a new generator from a 64-bit state.

pub const fn mix64(x: u64) -> u64

Applies the SplitMix64 output mixer.

pub const fn next_u64(&mut self) -> u64

Advances the state and returns the next value.

pub const fn fill_bytes(&mut self, buffer: &mut [u8])

Fills the buffer with generated bytes.

Trait Implementations

impl Clone for SplitMix64

fn clone(&self) -> SplitMix64

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl ConstInit for SplitMix64

Provides a fixed default initialized value.

const INIT: Self

Returns the compile-time “initial value” for a type.

impl Copy for SplitMix64

impl Debug for SplitMix64

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SplitMix64

Creates SplitMix64::INIT as the default value.

fn default() -> Self

Returns the “default value” for a type.

impl Eq for SplitMix64

impl PartialEq for SplitMix64

fn eq(&self, other: &SplitMix64) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RandSeedable for SplitMix64

type RandSeed = [u8; 8]

Byte-backed seed material accepted by this type.

fn rand_from_seed(seed: Self::RandSeed) -> Self

Constructs this type from explicit seed material.

fn rand_try_from_source<R>(source: &mut R) -> Result<Self, R::Error>

where R: RandTry + ?Sized,

Attempts to construct this type by drawing seed material from source.

fn rand_from_source<R>(source: &mut R) -> Self

where R: Rand + ?Sized,

Constructs this type by drawing seed material from an infallible source.

impl RandTry for SplitMix64

const RAND_OUTPUT_BITS: u32 = 64

Number of bits produced per output step.

const RAND_STATE_BITS: u32 = 64

Size of the source state owned by this value, in bits.

const RAND_QUALITIES: RandQualities = RandQualities::PRNG

Semantic qualities of this random source.

type Error = Infallible

Error returned when complete random data could not be produced.

fn rand_try_next_u64(&mut self) -> InfallibleResult<u64>

Attempts to produce the next 64 bits of randomness.

fn rand_try_fill_bytes(&mut self, buffer: &mut [u8]) -> InfallibleResult<()>

Attempts to fill the buffer with generated bytes.

fn rand_qualities(&self) -> RandQualities

Returns the semantic qualities of this random source.

fn rand_try_next_u128(&mut self) -> Result<u128, Self::Error>

Attempts to produce the next random u128.

fn rand_try_next_u32(&mut self) -> Result<u32, Self::Error>

Attempts to produce the next random u32.

fn rand_try_next_u16(&mut self) -> Result<u16, Self::Error>

Attempts to produce the next random u16.

fn rand_try_next_u8(&mut self) -> Result<u8, Self::Error>

Attempts to produce the next random u8.

fn rand_try_next_bool(&mut self) -> Result<bool, Self::Error>

Attempts to produce a random boolean.

fn rand_try_below(&mut self, upper: u64) -> Result<u64, Self::Error>

Attempts to return a uniformly random integer in 0..upper.

fn rand_try_range(&mut self, low: u64, high: u64) -> Result<u64, Self::Error>

Attempts to return a uniformly random integer in low..high.

fn rand_try_roll(&mut self, sides: u64) -> Result<u64, Self::Error>

Attempts to roll a fair die with a number of sides.

fn rand_try_shuffle<T>(&mut self, slice: &mut [T]) -> Result<(), Self::Error>

Attempts to shuffle the elements of the slice in place.

fn rand_try_choose_reservoir<I, F>( &mut self, iter: I, valid: F, ) -> Result<Option<I::Item>, Self::Error>

where I: IntoIterator, F: FnMut(&I::Item) -> bool,

Attempts to choose one valid item using reservoir sampling.

fn rand_try_choose_scored<I, F>( &mut self, iter: I, valid: F, ) -> Result<Option<I::Item>, Self::Error>

where I: IntoIterator, F: FnMut(&I::Item) -> bool,

Attempts to choose one valid item using random scores.

impl SeedableRng for SplitMix64

Available on crate feature dep_rand_core only.

type Seed = <SplitMix64 as RandSeedable>::RandSeed

Seed type, which is restricted to types mutably-dereferenceable as u8 arrays (we recommend [u8; N] for some N).

fn from_seed(seed: Self::Seed) -> Self

Create a new PRNG using the given seed.

fn seed_from_u64(state: u64) -> Self

Create a new PRNG using a u64 seed.

fn from_rng<R>(rng: &mut R) -> Self

where R: Rng + ?Sized,

Create a new PRNG seeded from an infallible Rng.

fn try_from_rng<R>(rng: &mut R) -> Result<Self, <R as TryRng>::Error>

where R: TryRng + ?Sized,

Create a new PRNG seeded from a potentially fallible Rng.

fn fork(&mut self) -> Self

where Self: Rng,

Fork this PRNG

fn try_fork(&mut self) -> Result<Self, Self::Error>

where Self: TryRng,

Fork this PRNG

impl StructuralPartialEq for SplitMix64

impl TryRng for SplitMix64

Available on crate feature dep_rand_core only.

type Error = <SplitMix64 as RandTry>::Error

The type returned in the event of a RNG error.

fn try_next_u32(&mut self) -> Result<u32, Self::Error>

Return the next random u32.

fn try_next_u64(&mut self) -> Result<u64, Self::Error>

Return the next random u64.

fn try_fill_bytes(&mut self, dst: &mut [u8]) -> Result<(), Self::Error>

Fill dst entirely with random data.