Struct Rng 

pub struct Rng { /* private fields */ }

A SplitMix64 generator. Fast, good statistical quality, single-word state.

Implementations

impl Rng

pub fn new(seed: u64) -> Self

Creates an RNG from a seed.

pub fn split(seed: u64, id: u64) -> Self

Derives an independent generator for parallel stream id.

The child seed is mix_seed(seed, id), so different (seed, id) pairs give non-overlapping sub-streams deterministically — the basis for reproducible island/ensemble parallelism.

pub fn uniform(&mut self) -> f64

Uniform f64 in [0, 1) with 53 bits of mantissa.

pub fn uniform_in(&mut self, lo: f64, hi: f64) -> f64

Uniform f64 in [lo, hi] (the top end is reachable: lo + (hi−lo)·u with u half an ulp below 1 can round up to hi, which is fine for the inclusive bounds used throughout the crate).

pub fn normal(&mut self) -> f64

Standard normal sample via the Box–Muller transform.

pub fn index(&mut self, bound: usize) -> usize

usize uniform in [0, bound).

Uses a plain modulo reduction: the bias is ~bound/2⁶⁴ (immeasurable for the population/dimension sizes used here) and, unlike rejection sampling, it consumes exactly one draw — which keeps RNG consumption, and therefore byte-level reproducibility, independent of bound.

Panics

If bound == 0.

Trait Implementations

impl Clone for Rng

fn clone(&self) -> Rng

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Rng

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

Formats the value using the given formatter.