Hedgehog SplitMix64 WASM

High-performance WebAssembly implementation of the SplitMix64 splittable pseudorandom number generator.

Overview

This is a language-agnostic WebAssembly module that provides:

- SplitMix64 algorithm: High-quality 64-bit pseudorandom number generation
- Splittable streams: Create independent random number generators
- Deterministic: Same seed always produces same sequence
- High performance: ~6x faster than pure JavaScript implementations

Building

Requires wasm-pack:

``bash


From project root

bin/build-wasm

Or manually

cd hedgehog-splitmix-wasm
wasm-pack build --target web --out-dir pkg
`

Usage

$3

`typescript
import { Seed } from './hedgehog-splitmix-wasm/pkg';

// Create seed from number
const seed = new Seed(42);

// Generate random values
const { value, seed: nextSeed } = seed.next_u64();
const { value: bounded, seed: nextSeed2 } = seed.next_bounded(100);
const { value: boolean, seed: nextSeed3 } = seed.next_bool();

// Split into independent streams
const { left, right } = seed.split();
`

$3

The WASM module can be imported and used from any language that supports WebAssembly:

- Python (with wasmtime-py or similar)
- Go (with wasmtime-go)
- Rust (with wasmtime)
- C/C++ (with WASI)
- And many others

API

$3

- new Seed(value: u64) - Create seed from number
- Seed.from_parts(state: u64, gamma: u64) - Create from components
- seed.state - Get state component
- seed.gamma - Get gamma component
- seed.next_u64() - Generate next u64 and new seed
- seed.next_bounded(bound: u64) - Generate bounded value [0, bound)
- seed.next_bool() - Generate boolean
- seed.split() - Split into two independent seeds

Algorithm Details

Based on the SplitMix64 algorithm with these key properties:

- Period: 2^64 for each generator stream
- Quality: Passes statistical randomness tests
- Splitting: Creates mathematically independent streams
- Performance: Optimized for speed and small WASM binary size

$3

- Golden ratio: 0x9e3779b97f4a7c15
- Mix multipliers: 0xbf58476d1ce4e5b9, 0x94d049bb133111eb`

License

BSD-3-Clause (same as parent project)