Remove failed STRUMPACK CI experiments

Delete experimental workflows that never worked:
- build-petsc-strumpack.yml
- gpu-build-test.yml
- test-strumpack job from CI.yml

Author: Sébastien Loisel

.github/workflows/CI.yml

@@ -59,86 +59,3 @@ jobs:
           files: lcov.info
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: false
-
-  test-strumpack:
-    name: Test with STRUMPACK
-    runs-on: ubuntu-latest
-    timeout-minutes: 30
-
-    env:
-      PETSC_RELEASE_TAG: petsc-strumpack
-
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Install CUDA runtime
-        run: |
-          sudo apt-get update
-          # Only install CUDA runtime (MPI is bundled in the tarball)
-          sudo apt-get install -y nvidia-cuda-toolkit
-
-      - uses: julia-actions/setup-julia@v2
-        with:
-          version: '1.10'
-          arch: x64
-
-      # Note: Intentionally NOT using julia-actions/cache@v2 here
-      # The cache would restore MPI.jl compiled against JLL MPI, conflicting
-      # with the bundled MPICH in the pre-built PETSc tarball
-
-      - name: Download pre-built PETSc STRUMPACK
-        run: |
-          echo "Downloading $PETSC_RELEASE_TAG..."
-          gh release download $PETSC_RELEASE_TAG --pattern "*.tar.gz" --dir /tmp
-          echo "Extracting..."
-          mkdir -p /tmp/petsc_strumpack
-          tar -xzf /tmp/${PETSC_RELEASE_TAG}.tar.gz -C /tmp/petsc_strumpack
-          echo "Done. Library at /tmp/petsc_strumpack/lib/libpetsc.so"
-          echo "Contents of lib/:"
-          ls -la /tmp/petsc_strumpack/lib/
-          echo "Contents of bin/:"
-          ls -la /tmp/petsc_strumpack/bin/
-        env:
-          GH_TOKEN: ${{ github.token }}
-
-      - name: Configure MPI to use bundled MPICH
-        run: |
-          # Write LocalPreferences.toml directly to configure MPI.jl
-          # This will be picked up by julia-buildpkg
-          cat > LocalPreferences.toml << 'EOF'
-          [MPIPreferences]
-          _format = "1.0"
-          abi = "MPICH"
-          binary = "system"
-          libmpi = "/tmp/petsc_strumpack/lib/libmpi.so"
-          mpiexec = "/tmp/petsc_strumpack/bin/mpiexec"
-          EOF
-          # Remove leading whitespace from TOML (heredoc includes YAML indentation)
-          sed -i 's/^[[:space:]]*//' LocalPreferences.toml
-          echo "LocalPreferences.toml:"
-          cat LocalPreferences.toml
-
-      - name: Build package
-        env:
-          LD_LIBRARY_PATH: /tmp/petsc_strumpack/lib
-        uses: julia-actions/julia-buildpkg@v1
-
-      - name: Verify MPI configuration
-        env:
-          LD_LIBRARY_PATH: /tmp/petsc_strumpack/lib
-        run: |
-          julia --project=. -e '
-            using MPI
-            println("MPI library: ", MPI.libmpi)
-            println("mpiexec: ", MPI.mpiexec())
-          '
-
-      - name: Run tests with STRUMPACK
-        env:
-          JULIA_PETSC_LIBRARY: /tmp/petsc_strumpack/lib/libpetsc.so
-          LD_LIBRARY_PATH: /tmp/petsc_strumpack/lib
-          MPIEXEC_PATH: /tmp/petsc_strumpack/bin/mpiexec
-        run: |
-          # Run tests directly instead of Pkg.test() to preserve LocalPreferences.toml
-          # (Pkg.test() creates a fresh temp environment that loses MPI preferences)
-          julia --project=. test/runtests.jl