feat(mtagro): enable muti-rank usage

.github/workflows/metatomic-ci.yml

@@ -0,0 +1,79 @@
+name: Metatomic Integration Tests
+
+on:
+  workflow_dispatch:
+    inputs:
+      pixi_envs_branch:
+        description: "pixi_envs branch for test definitions"
+        required: false
+        default: "main"
+  push:
+    branches: [metatomic]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - mpi: thread-mpi
+            build_task: gromk-tmpi
+            gmx_bin: gmx
+          - mpi: real-mpi
+            build_task: gromk-mpi
+            gmx_bin: gmx_mpi
+
+    name: metatomic (${{ matrix.mpi }})
+
+    steps:
+      - name: Checkout GROMACS
+        uses: actions/checkout@v4
+        with:
+          path: gromacs
+
+      - name: Checkout pixi_envs
+        uses: actions/checkout@v4
+        with:
+          repository: HaoZeke/pixi_envs
+          ref: ${{ github.event.inputs.pixi_envs_branch || 'main' }}
+          path: pixi_envs
+
+      - name: Place GROMACS inside pixi_envs layout
+        run: ln -s ${{ github.workspace }}/gromacs pixi_envs/orgs/metatensor/gromacs/gromacs
+
+      - name: Install pixi
+        uses: prefix-dev/setup-pixi@v0.8.1
+        with:
+          manifest-path: pixi_envs/orgs/metatensor/gromacs/pixi.toml
+          environments: metatomic-cpu
+
+      - name: Build GROMACS (${{ matrix.mpi }})
+        working-directory: pixi_envs/orgs/metatensor/gromacs
+        run: pixi run -e metatomic-cpu ${{ matrix.build_task }} Release
+
+      - name: Show cmake error log on failure
+        if: failure()
+        working-directory: pixi_envs/orgs/metatensor/gromacs
+        run: |
+          for f in gromacs/build-*/CMakeFiles/CMakeError.log; do
+            echo "=== $f ==="
+            cat "$f" 2>/dev/null || true
+          done
+          for f in gromacs/build-*/CMakeFiles/CMakeOutput.log; do
+            echo "=== $f (last 100 lines) ==="
+            tail -100 "$f" 2>/dev/null || true
+          done
+
+      - name: Generate test model
+        working-directory: pixi_envs/orgs/metatensor/gromacs
+        run: cd mta_test && pixi run -e metatomic-cpu python create_model.py
+
+      - name: Run tests (skip dd8/dd12)
+        working-directory: pixi_envs/orgs/metatensor/gromacs
+        env:
+          GMX_BIN: ${{ matrix.gmx_bin }}
+        run: |
+          pixi run -e metatomic-cpu pytest mta_test/ -v \
+            -m "not dd8 and not dd12"

cmake/gmxManageMetatomic.cmake

@@ -90,6 +90,25 @@ if(NOT GMX_METATOMIC STREQUAL "OFF")
         endif()
 
         set(GMX_TORCH ON)
+
+        # Ensure the torch library directory is in RPATH so that libtorch.so,
+        # libc10.so, etc. can be found at runtime. CMAKE_INSTALL_RPATH_USE_LINK_PATH
+        # doesn't always extract paths from imported targets, so we add it explicitly.
+        # Guard prevents duplicate additions if gmxManageNNPot already added it.
+        if(TORCH_INSTALL_PREFIX AND NOT _torch_rpath_added)
+            list(APPEND CMAKE_INSTALL_RPATH "${TORCH_INSTALL_PREFIX}/lib")
+            set(_torch_rpath_added TRUE)
+
+            # Use RPATH instead of RUNPATH. Modern linkers default to RUNPATH
+            # (--enable-new-dtags), but RUNPATH doesn't propagate to transitive
+            # dependencies: gmx -> libgromacs.so -> libtorch.so -> libc10.so.
+            include(CheckLinkerFlag)
+            check_linker_flag(CXX "-Wl,--disable-new-dtags" _linker_supports_disable_new_dtags)
+            if(_linker_supports_disable_new_dtags)
+                add_link_options("-Wl,--disable-new-dtags")
+            endif()
+        endif()
+
     elseif(GMX_METATOMIC STREQUAL "TORCH")
         message(FATAL_ERROR "Torch not found. Please install libtorch and add its installation prefix"
                             " to CMAKE_PREFIX_PATH or set Torch_DIR to a directory containing "

cmake/gmxManageNNPot.cmake

@@ -90,6 +90,22 @@ if(NOT GMX_NNPOT STREQUAL "OFF")
         endif()
 
         set(GMX_TORCH ON)
+
+        # Ensure the torch library directory is in RPATH so that libtorch.so,
+        # libc10.so, etc. can be found at runtime.
+        if(TORCH_INSTALL_PREFIX AND NOT _torch_rpath_added)
+            list(APPEND CMAKE_INSTALL_RPATH "${TORCH_INSTALL_PREFIX}/lib")
+            set(_torch_rpath_added TRUE)
+
+            # Use RPATH instead of RUNPATH. RUNPATH doesn't propagate to
+            # transitive dependencies (gmx -> libgromacs -> libtorch -> libc10).
+            include(CheckLinkerFlag)
+            check_linker_flag(CXX "-Wl,--disable-new-dtags" _linker_supports_disable_new_dtags)
+            if(_linker_supports_disable_new_dtags)
+                add_link_options("-Wl,--disable-new-dtags")
+            endif()
+        endif()
+
     elseif(GMX_NNPOT STREQUAL "TORCH")
         message(FATAL_ERROR "Torch not found. Please install libtorch and add its installation prefix"
                             " to CMAKE_PREFIX_PATH or set Torch_DIR to a directory containing "