Pin jax to 0.11.0 in CI -- jax 0.11.1 hangs the fori_loop cells on CPU

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>

Author: mmcky

.github/workflows/cache.yml

@@ -17,6 +17,15 @@ jobs:
           python-version: "3.13"
           environment-file: environment.yml
           activate-environment: quantecon
+      - name: Install JAX (CPU, pinned)
+        shell: bash -l {0}
+        run: |
+          # Pinned: jax 0.11.1 (2026-08-17) hangs numpy_vs_numba_vs_jax's
+          # lax.fori_loop cells on the CPU path -- context is recorded in
+          # QuantEcon/workspace-lectures#49. With jax already present, the
+          # lecture's unpinned `!pip install quantecon jax` cell is satisfied
+          # and does not upgrade.
+          pip install "jax==0.11.0"
       - name: Build HTML
         shell: bash -l {0}
         run: |

.github/workflows/ci.yml

@@ -22,6 +22,15 @@ jobs:
           python-version: "3.13"
           environment-file: environment.yml
           activate-environment: quantecon
+      - name: Install JAX (CPU, pinned)
+        shell: bash -l {0}
+        run: |
+          # Pinned: jax 0.11.1 (2026-08-17) hangs numpy_vs_numba_vs_jax's
+          # lax.fori_loop cells on the CPU path -- context is recorded in
+          # QuantEcon/workspace-lectures#49. With jax already present, the
+          # lecture's unpinned `!pip install quantecon jax` cell is satisfied
+          # and does not upgrade.
+          pip install "jax==0.11.0"
       - name: Display Conda Environment Versions
         shell: bash -l {0}
         run: conda list

.github/workflows/publish.yml

@@ -35,6 +35,15 @@ jobs:
           python-version: "3.13"
           environment-file: environment.yml
           activate-environment: quantecon
+      - name: Install JAX (CPU, pinned)
+        shell: bash -l {0}
+        run: |
+          # Pinned: jax 0.11.1 (2026-08-17) hangs numpy_vs_numba_vs_jax's
+          # lax.fori_loop cells on the CPU path -- context is recorded in
+          # QuantEcon/workspace-lectures#49. With jax already present, the
+          # lecture's unpinned `!pip install quantecon jax` cell is satisfied
+          # and does not upgrade.
+          pip install "jax==0.11.0"
       - name: Display Conda Environment Versions
         shell: bash -l {0}
         run: conda list