seed

→int

seed()

source edit

Seed the default generator from the OS cryptographic entropy source.

Reads 8 bytes from the operating system's secure random pool (/dev/urandom on macOS / Linux, CryptGenRandom on Windows) and uses them as the 63-bit Philox seed key $k$ :

k = \text{OS\_urandom}(8) \;\bmod\; 2^{63}

The 63-bit mask ensures the seed fits comfortably in a signed int64, which is required by the C++ Generator API. After seeding, the RNG counter $c$ is reset to $0$ .

Returns

int

The 63-bit seed value that was applied, so the caller can log or checkpoint it for later reproducibility.

Notes

Unlike manual_seed, successive calls to seed produce different streams with overwhelming probability ( $2^{63}$ possible seeds). Use this at the start of non-reproducible training runs and log the return value so you can reproduce the exact run later with lucid.manual_seed(returned_value) if needed.

The OS entropy pool on Apple Silicon is hardware-backed (the Secure Enclave contributes entropy), so the seeds are cryptographically unpredictable.

Examples

>>> import lucid
>>> s = lucid.seed()
>>> isinstance(s, int) and 0 <= s < 2**63
True
Log and reproduce:
>>> s = lucid.seed()
>>> print(f"Run seed: {s}")
>>> # Later, to reproduce:
>>> lucid.manual_seed(s)

>>> import lucid >>> s = lucid.seed() >>> isinstance(s, int) and 0 <= s < 2**63 True Log and reproduce: >>> s = lucid.seed() >>> print(f"Run seed: {s}") >>> # Later, to reproduce: >>> lucid.manual_seed(s)