Add MPI support for std::optional

.github/workflows/build.yml

@@ -2,9 +2,9 @@ name: build
 
 on:
   push:
-    branches: [ unstable ]
+    branches: [ unstable, '[0-9]+.[0-9]+.x' ]
   pull_request:
-    branches: [ unstable ]
+    branches: [ unstable, '[0-9]+.[0-9]+.x' ]
   workflow_call:
   workflow_dispatch:
 
@@ -25,107 +25,100 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        include:
-          - {os: ubuntu-22.04, cc: gcc-12, cxx: g++-12, doc: OFF}
-          - {os: ubuntu-22.04, cc: clang-15, cxx: clang++-15, doc: ON}
-          - {os: macos-12, cc: gcc-12, cxx: g++-12, doc: OFF}
-          - {os: macos-12, cc: clang, cxx: clang++, doc: OFF}
+        os:  [ubuntu-24.04, macos-15]
+        cxx: [g++, clang++]
 
     runs-on: ${{ matrix.os }}
 
     steps:
     - uses: actions/checkout@v4
 
-    - uses: actions/cache/restore@v3
+    - uses: actions/cache/restore@v4
       with:
         path: ${{ env.CCACHE_DIR }}
-        key: ccache-${{ matrix.os }}-${{ matrix.cc }}-${{ github.run_id }}
-        restore-keys:
-          ccache-${{ matrix.os }}-${{ matrix.cc }}-
+        key: ccache-${{ matrix.os }}-${{ matrix.cxx }}-${{ github.run_id }}-${{ github.run_attempt }}
+        restore-keys: |
+          ccache-${{ matrix.os }}-${{ matrix.cxx }}-
+
+    - name: Set cxx variables
+      run: |
+        if [[ ${{ matrix.os }} == 'macos-15' && ${{ matrix.cxx }} == 'g++' ]]; then
+          echo "CXX=g++-15" >> $GITHUB_ENV
+        else
+          echo "CXX=${{ matrix.cxx }}" >> $GITHUB_ENV
+        fi
 
     - name: Install ubuntu dependencies
-      if: matrix.os == 'ubuntu-22.04'
+      if: ${{ contains(matrix.os, 'ubuntu') }}
       run: >
         sudo apt-get update &&
         sudo apt-get install lsb-release wget software-properties-common &&
-        wget -O /tmp/llvm.sh https://apt.llvm.org/llvm.sh && sudo chmod +x /tmp/llvm.sh && sudo /tmp/llvm.sh 15 &&
         sudo apt-get install
         ccache
-        clang-15
-        g++-12
+        cmake
+        ninja-build
+        clang
+        clang-tools
+        g++
         gfortran
         hdf5-tools
-        libblas-dev
-        libclang-15-dev
-        libc++-15-dev
-        libc++abi-15-dev
-        libomp-15-dev
+        libboost-dev
+        libclang-dev
+        libc++-dev
+        libc++abi-dev
+        libomp-dev
         libfftw3-dev
         libgfortran5
         libgmp-dev
         libhdf5-dev
-        liblapack-dev
+        libopenblas-dev
         libopenmpi-dev
         openmpi-bin
         openmpi-common
         openmpi-doc
-        python3-clang-15
+        python3-clang
         python3-dev
         python3-mako
         python3-mpi4py
         python3-numpy
         python3-pip
         python3-scipy
-        python3-sphinx
-        python3-nbsphinx
+        python3-ipython
 
-    - name: Install homebrew dependencies
-      if: matrix.os == 'macos-12'
+    - name: Set up virtualenv
       run: |
-        brew install ccache gcc@12 llvm hdf5 open-mpi openblas
-        mkdir $HOME/.venv
-        python3 -m venv $HOME/.venv/my_python
+        mkdir -p $HOME/.venv
+        python3 -m venv --system-site-packages $HOME/.venv/my_python
         source $HOME/.venv/my_python/bin/activate
-        pip install mako numpy scipy mpi4py
-        pip install -r requirements.txt
         echo "VIRTUAL_ENV=$VIRTUAL_ENV" >> $GITHUB_ENV
         echo "PATH=$PATH" >> $GITHUB_ENV
 
-    - name: Build doxygen
-      if: matrix.doc == 'ON'
-      env:
-        CC: ${{ matrix.cc }}
-        CXX: ${{ matrix.cxx }}
-        LIBRARY_PATH: /usr/local/opt/llvm/lib
+    - name: Install homebrew dependencies
+      if: ${{ contains(matrix.os, 'macos') }}
       run: |
-        cd $HOME
-        git clone https://github.com/doxygen/doxygen.git
-        cd doxygen
-        git checkout 0a7e79813
-        mkdir build
-        cd build
-        cmake .. -Duse_libclang=ON -Dstatic_libclang=ON -Duse_libc++=OFF -DLLVM_ROOT=/usr/lib/llvm-15/lib/cmake/llvm -DClang_ROOT=/usr/lib/llvm-15/lib/cmake/clang
-        make -j 2 VERBOSE=1
-        cp bin/doxygen /usr/local/bin/doxygen
+        brew update
+        brew install ccache gcc llvm hdf5 open-mpi openblas doxygen
+        pip install mako numpy scipy mpi4py
+        pip install -r requirements.txt
+        echo "PATH=$(brew --prefix llvm)/bin:$(brew --prefix gcc)/bin:$PATH" >> $GITHUB_ENV
+        echo "PYTHONPATH=$(brew --prefix llvm)/lib/python3.13/site-packages" >> $GITHUB_ENV
+        echo "SDKROOT=$(xcrun --show-sdk-path)" >> $GITHUB_ENV
+        echo "LDFLAGS=-L$(brew --prefix llvm)/lib/c++ -L/opt/homebrew/opt/llvm/lib/unwind -lunwind" >> $GITHUB_ENV
 
-    - name: add clang cxxflags
-      if: ${{ contains(matrix.cxx, 'clang') }}
+    - name: Add clang CXXFLAGS
+      if: ${{ matrix.cxx == 'clang++' }}
       run: |
-        echo "PATH=/usr/local/opt/llvm/bin:$PATH" >> $GITHUB_ENV
         echo "CXXFLAGS=-stdlib=libc++" >> $GITHUB_ENV
 
     - name: Build mpi
       env:
-        CC: ${{ matrix.cc }}
-        CXX: ${{ matrix.cxx }}
-        LIBRARY_PATH: /usr/local/opt/llvm/lib
+        BUILD_DOXYGEN_DOCS: ${{ matrix.os == 'macos-15' && matrix.cxx == 'clang++' && 'ON' || 'OFF' }}
       run: |
-        mkdir build && cd build && cmake .. -DCMAKE_INSTALL_PREFIX=$HOME/install -DBuild_Documentation=${{ matrix.doc }}
-        make -j2 || make -j1 VERBOSE=1
+        cmake -S . -B build -G Ninja -DCMAKE_INSTALL_PREFIX=$HOME/install -DBuild_Documentation=$BUILD_DOXYGEN_DOCS
+        cmake --build build --verbose
 
     - name: Test mpi
       env:
-        DYLD_FALLBACK_LIBRARY_PATH: /usr/local/opt/llvm/lib
         OPENBLAS_NUM_THREADS: "1"
       run: |
         cd build
@@ -135,14 +128,14 @@ jobs:
       if: always()
       run: ccache -sv
 
-    - uses: actions/cache/save@v3
+    - uses: actions/cache/save@v4
       if: always()
       with:
         path: ${{ env.CCACHE_DIR }}
-        key: ccache-${{ matrix.os }}-${{ matrix.cc }}-${{ github.run_id }}
+        key: ccache-${{ matrix.os }}-${{ matrix.cxx }}-${{ github.run_id }}-${{ github.run_attempt }}
 
     - name: Deploy documentation
-      if: matrix.doc == 'ON' && github.ref == 'refs/heads/unstable'
+      if: matrix.os == 'macos-15' && matrix.cxx == 'clang++' && github.ref == 'refs/heads/unstable'
       uses: JamesIves/github-pages-deploy-action@v4
       with:
         folder: build/doc/html

.github/workflows/build_multi_node.yml

@@ -0,0 +1,88 @@
+name: build_multi_node
+
+on:
+  push:
+    branches: [ unstable, '[0-9]+.[0-9]+.x' ]
+  pull_request:
+    branches: [ unstable, '[0-9]+.[0-9]+.x' ]
+  workflow_call:
+  workflow_dispatch:
+
+env:
+  CMAKE_C_COMPILER_LAUNCHER: ccache
+  CMAKE_CXX_COMPILER_LAUNCHER: ccache
+  CCACHE_COMPILERCHECK: content
+  CCACHE_BASEDIR: ${{ github.workspace }}
+  CCACHE_DIR: ${{ github.workspace }}/.ccache
+  CCACHE_MAXSIZE: 500M
+  CCACHE_SLOPPINESS: pch_defines,time_macros,include_file_mtime,include_file_ctime
+  CCACHE_COMPRESS: "1"
+  CCACHE_COMPRESSLEVEL: "1"
+
+jobs:
+  build_multi_node:
+
+    strategy:
+      fail-fast: false
+
+    runs-on: ubuntu-24.04
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - uses: actions/cache/restore@v4
+      with:
+        path: ${{ env.CCACHE_DIR }}
+        key: ccache-${{ matrix.os }}-${{ matrix.cc }}-${{ github.run_id }}-${{ github.run_attempt }}
+        restore-keys: |
+          ccache-${{ matrix.os }}-${{ matrix.cc }}-
+
+    - name: Install ubuntu dependencies
+      run: >
+        sudo apt-get update && sudo apt-get install ccache
+
+    - name: Build and start Docker Compose
+      run: |
+        docker compose build
+        docker compose up -d
+      working-directory: .github/workflows/docker
+
+    - name: Compile MPI inside the container
+      run: |
+        docker exec -t -u runner -w ${{ github.workspace }} docker-vm-1 /bin/bash -euxc '
+        cmake -S . -B build -DCMAKE_INSTALL_PREFIX=$HOME/install -DBuild_Documentation=Off
+        cmake --build build/ -j2
+        '
+
+    - name: Run tests inside the container
+      run: |
+        docker exec -t -u runner -w ${{ github.workspace }} docker-vm-1 /bin/bash -euxc '
+        export CTEST_OUTPUT_ON_FAILURE=1
+        cmake --build build/ --target test
+        '
+
+    - name: Run multi-node window tests
+      run: |
+        docker exec -t -u runner -w ${{ github.workspace }} docker-vm-1 /bin/bash -euxc '
+        cat <<EOF | tee hostfile
+        docker-vm-1 slots=3
+        docker-vm-2 slots=1
+        docker-vm-3 slots=2
+        EOF
+
+        # Test the communication
+        mpirun -hostfile ./hostfile /bin/bash -c "env | grep \"^OMPI_COMM_.*_RANK\""
+
+        # Run the actual test
+        mpirun -hostfile ./hostfile build/test/c++/mpi_window
+        '
+
+    - name: ccache statistics
+      if: always()
+      run: ccache -sv
+
+    - uses: actions/cache/save@v4
+      if: always()
+      with:
+        path: ${{ env.CCACHE_DIR }}
+        key: ccache-${{ matrix.os }}-${{ matrix.cc }}-${{ github.run_id }}-${{ github.run_attempt }}

.github/workflows/docker/Dockerfile

@@ -0,0 +1,26 @@
+FROM ubuntu:24.04
+ENV DEBIAN_FRONTEND=noninteractive
+RUN apt-get update \
+ && apt-get install --no-install-recommends -y \
+    ca-certificates \
+    build-essential \
+    ccache \
+    cmake \
+    g++ \
+    git \
+    libopenmpi-dev \
+    openmpi-bin \
+    openssh-server \
+ && rm -rf /var/cache/apt /var/lib/apt/lists
+RUN useradd -m runner \
+ && passwd -d runner \
+ && mkdir -pm0755 /run/sshd \
+ && echo "PermitRootLogin yes" >> /etc/ssh/sshd_config.d/99-insecure.conf \
+ && echo "PasswordAuthentication yes" >> /etc/ssh/sshd_config.d/99-insecure.conf \
+ && echo "PermitEmptyPasswords yes" >> /etc/ssh/sshd_config.d/99-insecure.conf \
+ && echo "StrictHostKeyChecking no" >> /etc/ssh/ssh_config.d/99-insecure.conf \
+ && echo "LogLevel ERROR" >> /etc/ssh/ssh_config.d/99-insecure.conf
+ENV OMPI_MCA_btl_vader_single_copy_mechanism=none
+ENV OMPI_MCA_osc=sm,pt2pt
+ENV OMPI_MCA_rmaps_base_oversubscribe=yes
+CMD ["/usr/sbin/sshd", "-D"]

.github/workflows/docker/docker-compose.yml

@@ -0,0 +1,20 @@
+services:
+  vm:
+    build: .
+    deploy:
+      mode: replicated
+      replicas: 3
+    environment:
+      CMAKE_C_COMPILER_LAUNCHER: ${CMAKE_C_COMPILER_LAUNCHER:-ccache}
+      CMAKE_CXX_COMPILER_LAUNCHER: ${CMAKE_CXX_COMPILER_LAUNCHER:-ccache}
+      CCACHE_COMPILERCHECK: ${CCACHE_COMPILERCHECK:-content}
+      CCACHE_BASEDIR: ${CCACHE_BASEDIR}
+      CCACHE_DIR: ${CCACHE_DIR:-${CCACHE_BASEDIR}/.ccache}
+      CCACHE_MAXSIZE: ${CCACHE_MAXSIZE:-500M}
+      CCACHE_SLOPPINESS: ${CCACHE_SLOPPINESS:-pch_defines,time_macros,include_file_mtime,include_file_ctime}
+      CCACHE_COMPRESS: ${CCACHE_COMPRESS:-1}
+      CCACHE_COMPRESSLEVEL: ${CCACHE_COMPRESSLEVEL:-1}
+    stdin_open: true
+    tty: true
+    volumes:
+      - ${CCACHE_BASEDIR}:${CCACHE_BASEDIR}:z

.gitignore

@@ -2,3 +2,5 @@ compile_commands.json
 doc/_autosummary
 doc/cpp2rst_generated
 doc/html
+.claude
+build/

CMakeLists.txt

@@ -15,10 +15,7 @@
 # Authors: Philipp Dumitrescu, Olivier Parcollet, Dylan Simon, Nils Wentzell
 
 cmake_minimum_required(VERSION 3.20 FATAL_ERROR)
-cmake_policy(VERSION 3.20)
-if(POLICY CMP0144)
-  cmake_policy(SET CMP0144 NEW)
-endif()
+cmake_policy(VERSION ${CMAKE_VERSION})
 
 # ############
 # Define Project

README.md

@@ -7,3 +7,13 @@ mpi is a high-level C++ interface to the [Message Passing Interface](https://en.
 A reference documentation based on [Doxygen](https://www.doxygen.nl) is provided at [triqs.github.io/mpi](https://triqs.github.io/mpi).
 
 For usage examples we refer the users to our [tests](https://github.com/TRIQS/mpi/tree/unstable/test/c++).
+
+## Support
+
+<picture>
+  <source media="(prefers-color-scheme: dark)" width="20%" srcset="doc/_static/CCQ-dark.png">
+  <img alt="Flatiron Center for Computational Quantum Physics logo." width="20%" src="doc/_static/CCQ.png">
+</picture>
+
+TRIQS/mpi is supported by the Flatiron Institute, a division of the Simons Foundation.
+

c++/mpi/CMakeLists.txt

@@ -26,6 +26,7 @@ target_link_libraries(${PROJECT_NAME}_c INTERFACE itertools::itertools_c)
 message(STATUS "-------- MPI detection -------------")
 
 set(MPI_CXX_SKIP_MPICXX TRUE CACHE BOOL "If true, the MPI-2 C++ bindings are disabled using definitions.")
+set(MPI_DETERMINE_LIBRARY_VERSION TRUE)
 find_package(MPI REQUIRED COMPONENTS CXX)
 
 # Create an interface target
@@ -51,11 +52,11 @@ if(NOT MPIEXEC_EXECUTABLE)
   set(MPIEXEC_EXECUTABLE ${MPIEXEC} CACHE FILENAME "MPI Executable")
 endif()
 
-# Compatibility to Open-MPI 3.0.0: check whether MPI executable has option --oversubscribe and add it
-execute_process(COMMAND ${MPIEXEC_EXECUTABLE} --oversubscribe ${MPIEXEC_NUMPROC_FLAG} 4 ${MPIEXEC_PREFLAGS} ls ${MPIEXEC_POSTFLAGS} RESULT_VARIABLE HAS_NO_OVERSUBSCRIBE OUTPUT_QUIET ERROR_QUIET)
-if(NOT HAS_NO_OVERSUBSCRIBE)
+# Open-MPI 3.0+ requires --oversubscribe flag
+if(MPI_CXX_LIBRARY_VERSION_STRING MATCHES "Open MPI v([0-9]+)" AND CMAKE_MATCH_1 GREATER_EQUAL 3)
+  message(STATUS "MPI Version: ${MPI_CXX_LIBRARY_VERSION_STRING}")
   list(APPEND MPIEXEC_PREFLAGS --oversubscribe)
-  set(MPIEXEC_PREFLAGS ${MPIEXEC_PREFLAGS} CACHE STRING "These flags will be directly before the executable that is being run by mpiexec." FORCE)
+  set(MPIEXEC_PREFLAGS ${MPIEXEC_PREFLAGS} CACHE STRING "Flags to pass to mpiexec directly before the executable to run." FORCE)
 endif()
 
 # ========= Static Analyzer Checks ==========