tfp.random.sanitize_seed  |  TensorFlow Probability (original) (raw)

tfp.random.sanitize_seed

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Map various PRNG seed flavors to a seed Tensor.

tfp.random.sanitize_seed(
    seed, salt=None, name=None
)

Used in the notebooks

This function implements TFP's standard PRNG seeding semantics. See https://github.com/tensorflow/probability/blob/main/PRNGS.mdfor details.

Operationally, sanitize_seed maps any seed flavor to a "stateless-compatible" seed. Under TensorFlow and NumPy this means:

• If the seed argument is an int or None, we use tf.random.uniformto statefully draw a pair of unbounded int32s and wrap them into a Tensor.
• If the seed argument is a stateless-compatible seed already, we just cast it to an int32[2] Tensor.

Under JAX, this function only accepts outputs from jax.random.PRNGKey, being a no-op except for the salting behavior described below.

This, any function that accepts a seed argument can be written in stateless-seed style internally, and acquires TFP's seed-type-directed stateless/stateful switching behavior by just running the input seed through sanitize_seed on entry.

The sanitize_seed function also allows salting the seed: if a user accidentally passes the same stateful seed to two different calls tosanitize_seed with different salts, they will get independent randomness. We may micro-optimize by removing salting fromsanitize_seed of already-stateless seeds in the future, as using a stateless seed already requires seed uniqueness discipline.