Checkpointing of a T5 model results in serialization error with new Jax 0.4.5

[emersodb]

Flax has removed optim in favor of optax in its newest versions above 0.5.3. This means that in order to run the code in this repository, one needs to downgrade below Flax 0.6. However, if you do that with Jax 0.4.5 or even with Jax 0.3.25 + jax.config.update('jax_array', True), the code cannot save a model checkpoint due to msgpack being unable to serialize the jax arrays.

Expected Behavior

Model should be able to be saved as a checkpoint.

Actual Behavior

Steps to Reproduce the Problem

With Jax 0.4.5 and Flax 0.5.3 one can minimally recreate this issue in a python repl as

[wzq016]

Hi, I also have the same problem. I think it is because of the inconsistency between prompt-tuning and t5x. To fix it, I check the release date of dependencies, prompt-tuning repo, and t5x repo, and find a combination that can work.

PT version: 287949b546999d34eafc3770fc1b2320074912b3
T5X version: e5f61889114b2cb5bbfa916eb1ec35e6767427a0
jax==0.3.15, jax[tpu]==0.3.15
libtpu-nightly==0.1.dev20220722
jaxlib==0.3.15
flax==0.5.3
clu==0.0.7
numpy=1.23.4
orbax==0.0.4
protobuf==3.19.6
seqio==0.0.8

There may be better solutions though.

[emersodb]

Thanks for the response. I've tried doing these downgrades. I was able to get everything built in a python env properly, but I'm running into mysterious cuda and NCCL errors that I wasn't getting before, which is a whole different issue. I'll see if I can make it work and report back. Ideally, this type of version matching wouldn't be necessary.