refine CI

Author: cw-tan

.github/workflows/tests.yaml

@@ -33,7 +33,7 @@ jobs:
 
   tests:
     needs: lint
-    runs-on: ${{ github.event.repository.private == true && 'self-hosted' || 'ubuntu-latest' }}
+    runs-on: ${{ github.event.repository.private && 'self-hosted' || 'ubuntu-latest' }}
     strategy:
       matrix:
         torch-version: ["2.*"]
@@ -51,6 +51,15 @@ jobs:
         run: |
           python3 --version
           which python3
+      - name: Disable pip cache
+        run: |
+          echo "PIP_NO_CACHE_DIR=1" >> $GITHUB_ENV
+          echo "PIP_NO_CACHE=1" >> $GITHUB_ENV
+      - name: Configure torch cache directories
+        run: |
+          echo "TORCH_EXTENSIONS_DIR=/tmp/torch_extensions_${GITHUB_RUN_ID}_${GITHUB_RUN_ATTEMPT}" >> $GITHUB_ENV
+          echo "TORCHINDUCTOR_CACHE_DIR=/tmp/torchinductor_${GITHUB_RUN_ID}_${GITHUB_RUN_ATTEMPT}" >> $GITHUB_ENV
+          echo "TRITON_CACHE_DIR=/tmp/triton_${GITHUB_RUN_ID}_${GITHUB_RUN_ATTEMPT}" >> $GITHUB_ENV
       - name: Clone NequIP packages
         uses: mir-group/nequip-gh-actions/clone@main
         with: