Struct DetRng 

pub struct DetRng { /* private fields */ }

A deterministic pseudo-random number generator.

Uses a 64-bit LCG (Linear Congruential Generator) with PCG constants. Same seed always produces the same sequence — this is the foundation of Vortex’s reproducibility guarantee.

Implementations

impl DetRng

pub fn new(seed: u64) -> Self

Create a new RNG with the given seed.

pub fn derive(master_seed: u64, domain: &str) -> Self

Create a child RNG for a subsystem by mixing the master seed with a domain tag.

This ensures different subsystems (network, storage, clock) get independent but deterministic random streams from the same master seed.

let master = 42u64;
let net_rng = DetRng::derive(master, "network");
let disk_rng = DetRng::derive(master, "storage");
// net_rng and disk_rng produce different sequences

pub fn next_u64(&mut self) -> u64

Advance the RNG state and return the next raw u64.

pub fn next_f64(&mut self) -> f64

Return a random f64 in [0.0, 1.0).

pub fn next_u64_below(&mut self, max: u64) -> u64

Return a random u64 in [0, max) (exclusive upper bound).

pub fn next_u64_range(&mut self, min: u64, max: u64) -> u64

Return a random u64 in [min, max] (inclusive both bounds).

pub fn chance(&mut self, probability: f64) -> bool

Return true with the given probability [0.0, 1.0].

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

Shuffle a slice in-place (Fisher-Yates).

pub fn state(&self) -> u64

Get the current internal state (for debugging/logging).