pymc-devs / pymc-devs/pytensor
Implement JAX conversion for While Scan
Open
Nobody has claimed this yet.
backend compatibility
help wanted
jax
scan
- Dominant language
- Python
- Stars
- 644
- Forks
- 208
- Avg merge
- 2d 14h
- Merged PRs (30d)
- 16
Description
Description
https://github.com/pymc-devs/pytensor/pull/232 left this case out
IIRC, JAX can only JIT while loops with fixed output size, which means PyTensor while Scans where only the last state is used.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Review pytensor-devs/pytensor#232 and locate the existing JAX conversion path for While Scans. Start by tracing how scans with only the last state used are represented, then verify the implementation supports fixed-output-size while loops under JAX JIT. Done means this omitted case converts and executes correctly, with coverage for the relevant scan behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- machine-learning
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100