Pin jax to 0.11.0 in CI — jax 0.11.1 hangs the fori_loop cells on CPU - #37
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jax 0.11.1 (2026-08-17) regresses lax.fori_loop on the CPU path: numpy_vs_numba_vs_jax executes in seconds under 0.11.0 and exceeds even the new 1800s cell timeout under 0.11.1. This repo had no workflow-level jax install, so the lecture's unpinned '!pip install quantecon jax' cell resolved the broken release on every build. Full evidence and the family-wide exposure map are recorded in QuantEcon/workspace-lectures#49. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Pull request overview
This PR updates the repository’s GitHub Actions workflows to proactively install a known-good JAX version in CI/cache/publish runs, preventing a regression in lax.fori_loop CPU execution from breaking (or timing out) lecture builds.
Changes:
- Add a dedicated workflow step to
pip install "jax==0.11.0"(CPU) after the conda environment is created/activated. - Apply the same pin consistently across CI, cache rebuild, and publish workflows to keep execution/cache behavior aligned.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| .github/workflows/publish.yml | Pre-installs pinned JAX before building the site for GitHub Pages publishing. |
| .github/workflows/ci.yml | Pre-installs pinned JAX to keep PR preview builds from pulling the regressed release. |
| .github/workflows/cache.yml | Pre-installs pinned JAX so the main-branch cache rebuild executes lectures under the stable version. |
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jax/jaxlib 0.11.1 (released 2026-08-17 20:31 UTC) regresses
lax.fori_loopon the CPU execution path:numpy_vs_numba_vs_jaxexecutes in seconds under 0.11.0 and exceeds even an 1800 s cell timeout under 0.11.1 (locally bisected — the same jitted fori_loop hangs with and without the deprecateddevice=cpuargument). This repo had no workflow-level jax install at all, so the lecture pip cell resolved the broken release on every build — this is what failed the publish-2026aug19 run twice, at both 600 s and 1800 s ceilings. After merge, the on-push cache rebuild should finally carry the executed lecture, and the failed publish run can be re-run.The full evidence chain, family exposure map, and the unpin condition are recorded in QuantEcon/workspace-lectures#49. One PR per repo with this same change; with jax pre-installed, the lecture's unpinned
!pip install quantecon jaxcell is satisfied and does not upgrade.🤖 Generated with Claude Code