Universal RNG

A collection of efficient pseudo-random number generators (PRNGs) implemented in pure Rust. This crate provides a wide variety of algorithms, ranging from standard Mersenne Twister to modern high-performance generators like Xoshiro and Philox.

Installation

Add this to your Cargo.toml:

[dependencies]
urng = "0.4.9"

Supported Generators

Generators are divided into two categories: standard generators and AVX-accelerated SIMD generators. Standard generators implement either the Rng32 or Rng64 trait (or return fixed-size arrays for counter-based variants). AVX generators expose a bulk-generation API and are listed separately.

32-bit Generators (urng::rng32)

64-bit Generators (urng::rng64)

SIMD Generators (AVX)

These generators expose a bulk-generation API and require AVX support at runtime.

AVX2 (avx2)

AVX-512 (avx512f)

Sampler

Requires the sampler feature.

Weighted random index selection. Two implementations are provided for each bit-width, both implementing the Sampler32 / Sampler64 trait (urng::sampler).

SeedGen

Requires the seedgen feature.

Hardware-noise-assisted seed generation. Wraps an existing Rng32/Rng64 and mixes in hardware noise (RDSEED/RDRAND on x86/x86_64, timestamp fallback elsewhere) via a Murmur3-style hash.

next_seed_pair() returns (raw, processed) — the raw hardware value and the mixed seed.

Usage Examples

Most generators expose the same basic workflow: create an instance with new, then use nextu, nextf, randi, randf, or choice depending on the output type you need. SIMD and counter-based generators return fixed-size arrays instead of single values.

Basic Usage

use urng::prelude::*;

fn main() {
    // 1. Initialize with a seed
    let mut rng = Xoshiro256Pp::new(12345);

    // 2. Generate random numbers
    let val_u64 = rng.nextu();
    println!("u64: {}", val_u64);

    let val_f64 = rng.nextf(); // [0.0, 1.0)
    println!("f64: {}", val_f64);

    // 3. Generate within a range
    let val_range = rng.randi(1, 100);
    println!("Integer (1-100): {}", val_range);

    // 4. Seeding with SplitMix64 (common pattern)
    // If you need to seed a large state generator from a single u64
    let mut sm = SplitMix64::new(9999);
    let seed_val = sm.nextu();
    let mut rng2 = Xoshiro256Pp::new(seed_val);
}

C ABI

This crate exports a C-compatible ABI generic interface. Each generator has corresponding:

• _new
• _free
• _next_uXXs (bulk generation)
• _next_fXXs (bulk generation)
• _rand_iXXs (bulk generation)
• _rand_fXXs (bulk generation)

Example for Mt19937:

void* mt19937_new(uint32_t seed, size_t warm);
void mt19937_next_u32s(void* ptr, uint32_t* out, size_t count);
void mt19937_rand_f32s(void* ptr, float* out, size_t count, float min, float max);
void mt19937_free(void* ptr);