Struct SplitMix64 

pub struct SplitMix64 { /* private fields */ }

A deterministic 64-bit stream. Cheap enough to make one per request.

Implementations

impl SplitMix64

pub fn new(seed: u64) -> SplitMix64

pub fn derive(seed: u64, label: &str) -> SplitMix64

Derive an independent stream from this one and a label, so two features seeded from the same run never correlate. (hash is FNV-1a, also here, also for stream stability.)

pub fn next_u64(&mut self) -> u64

pub fn below(&mut self, n: u64) -> u64

Uniform in [0, n). Rejection-sampled, not modulo: a modulo fold skews the low values, and a fault that fires 0.4 % too often is a fault whose measured rate is a lie.

pub fn chance(&mut self, num: u64, den: u64) -> bool

true with probability num / den.

pub fn range(&mut self, lo: u64, hi: u64) -> u64

Uniform in [lo, hi] inclusive.

pub fn shuffle<T>(&mut self, v: &mut [T])

Fisher–Yates, so a shuffled address pool is a permutation and never hands the same address to two servers.

Trait Implementations

impl Clone for SplitMix64

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SplitMix64

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

Formats the value using the given formatter.