MPI

添加 MPI 的方式类似于 OpenMP，所以最好使用 CMake 3.9+ 。

find_package(MPI REQUIRED)
message(STATUS "Run: ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${MPIEXEC_MAX_NUMPROCS} ${MPIEXEC_PREFLAGS} EXECUTABLE ${MPIEXEC_POSTFLAGS} ARGS")
target_link_libraries(MyTarget PUBLIC MPI::MPI_CXX)

若需要支持旧版 CMake，可以使用 3.1+ 版本来模仿上面的方式：

find_package(MPI REQUIRED)

# For supporting CMake < 3.9:

if(NOT TARGET MPI::MPI_CXX)
    add_library(MPI::MPI_CXX IMPORTED INTERFACE)

    set_property(TARGET MPI::MPI_CXX
                 PROPERTY INTERFACE_COMPILE_OPTIONS ${MPI_CXX_COMPILE_FLAGS})
    set_property(TARGET MPI::MPI_CXX
                 PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${MPI_CXX_INCLUDE_PATH}")
    set_property(TARGET MPI::MPI_CXX
                 PROPERTY INTERFACE_LINK_LIBRARIES ${MPI_CXX_LINK_FLAGS} ${MPI_CXX_LIBRARIES})
endif()

message(STATUS "Run: ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${MPIEXEC_MAX_NUMPROCS} ${MPIEXEC_PREFLAGS} EXECUTABLE ${MPIEXEC_POSTFLAGS} ARGS")
target_link_libraries(MyTarget PUBLIC MPI::MPI_CXX)