xoshiro.nx

xoshiro.nx -- xoshiro256++ pseudorandom number generator. David Blackman + Sebastiano Vigna 2018. 256-bit state, 64-bit output per step, period 2^256 - 1. Passes BigCrush statistical tests. Used by: Rust `rand` standard generator, Lua 5.4, GNU FORTRAN, .NET 6+. NOT cryptographically secure -- an attacker who observes enough output can reconstruct state. For crypto use rand.nx (/dev/urandom) or HMAC-DRBG (pending). Used for: simulation, deterministic test data, sampling, fuzzing. When you need REPRODUCIBLE pseudorandom from a seed. Invariants: X1 64-bit output per step; full state advances. X2 Same seed -> same output sequence forever. X3 All-zeros state forbidden (would produce all zeros). seed_with implements the SplitMix64 trick to safely initialise from any 64-bit seed including 0.