[graphcast] Prepare for jax_pmap_shmap_merge=True.#5168
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[graphcast] Prepare for jax_pmap_shmap_merge=True.#5168copybara-service[bot] wants to merge 1 commit intomainfrom
jax_pmap_shmap_merge=True.#5168copybara-service[bot] wants to merge 1 commit intomainfrom
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This change: - Inlines `jax.device_put_sharded` to take an `axis_name` so we can make sure the resulting axis name in the `NamedSharding` matches what the new pmap expects. `_device_put_sharded` falls back to the original `jax.device_put_sharded` when `jax_pmap_shmap_merge=False`. - Strips sharding metadata from RNG keys after pmapped `split_rng_fn` calls. There is a small performance penalty and not ideal, but is less intrusive of a change than making sure all user `predictor_fn`s `pmap` with the same devices. See https://docs.jax.dev/en/latest/migrate_pmap.html for more information. PiperOrigin-RevId: 846566054
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[graphcast] Prepare for
jax_pmap_shmap_merge=True.This change:
jax.device_put_shardedto take anaxis_nameso we can make sure the resulting axis name in theNamedShardingmatches what the new pmap expects._device_put_shardedfalls back to the originaljax.device_put_shardedwhenjax_pmap_shmap_merge=False.split_rng_fncalls. There is a small performance penalty and not ideal, but is less intrusive of a change than making sure all userpredictor_fnspmapwith the same devices.See https://docs.jax.dev/en/latest/migrate_pmap.html for more information.