There can only be one (MPI process)!

MPILander is a single-rank mock library. It aims to implement a full MPI 3.1 standard compatible MPI library with the most trivial program path: allowing only one MPI process (rank)!

MPILander is perfect for massively parallel applications and libraries that also run well in single-rank mode. Often one faces the problem that either the main application or its dependencies are heavily relying on MPI functionality. This complicates starting with one rank (e.g., still needs to call mpiexec) in many environments such as CI or intentionally serial (debug) workflows.

MPILander is here to help you with that. Keep your regular MPI hard-wiring in place - and it will implement and provide everything you would expect from a MPI library, but only for exactly one and only one rank.

• CMake 3.9.2+
• C++11 capable compiler, e.g. g++ 4.8+, clang 3.9+, VS 2015+

spack install mpilander
spack load mpilander

MPILander can be installed using CMake:

git clone https://github.com/MPILander/MPILander.git

mkdir -p MPILander-api-build
cd MPILander-api-build

# optional:        -DCMAKE_INSTALL_PREFIX=$HOME/somepath
cmake ../MPILander

cmake --build .

# optional
ctest

# sudo might be required for system paths
cmake --build . --target install

By default, this will build as a static library (libmpi.a) and installs also its headers. In order to build a static library, append -DBUILD_SHARED_LIBS=ON to the cmake command. You can only build a static or a shared library at a time.

By default, the Release version is built. In order to build with debug symbols, pass -DCMAKE_BUILD_TYPE=Debug to your cmake command.

By default, tests and examples are built. In order to skip building those, pass -DBUILD_TESTING=OFF or -DBUILD_EXAMPLES to your cmake command.

If your project is using CMake for its build, one can conveniently use our provided Config.cmake package which is installed alongside the library.

First set the following environment hint if MPILander was not installed in a system path:

# optional: only needed if installed outside of system paths
export CMAKE_PREFIX_PATH=$HOME/somepath:$CMAKE_PREFIX_PATH

Use the following lines in your projects CMakeLists.txt:

find_package(MPILander 0.1.0 CONFIG)

if(MPILander_FOUND)
    target_link_libraries(YourTarget PUBLIC MPILander::MPILander)
endif()

Alternatively, add the MPILander repository directly to your project and add it via

add_subdirectory("path/to/source/of/MPILander")

target_link_libraries(YourTarget PRIVATE MPILander::MPILander)