mpilib20

This library provides both free subroutine and object-orientated bindings to MPI fortran, whilst maintaining standard MPI naming conventions as far as possible and avoiding the use of non-standard preprocessing. The plan is to support both CMake and Meson build systems, and incorporate a unit testing framework.

Project Goals

• Produce a decent set of fortran wrappers for MPI that can be used in subsequent projects
• Test bed for writing better CMake and learning meson
• Explore both unit test and app test frameworks for MPI applications
• Provide a means of reusing Alex's standalone MPI tests
• Provide a home for more exotic communicator splitting and topology wrappers
• Get Max into MPI

Building with CMake

The project Cmake has been written to include compiler warnings and flags for both GCC and Intel, for all supported build types. Build types currently supported are: Release, Debug and RelWithDebInfo, with support for MinSizeRel to be added.

To build in debug mode, one issues:

cmake ../ -DCMAKE\_BUILD\_TYPE=Debug

If no build type is specified, MPILib20 will build with RelWithDebInfo.

Additionally, one can also build with user-specified flags:

FFLAGS=-fopenmp cmake ../

although at present, these will append not overwrite the defaults.

Installing

To install MPILib20, the user can specify:

cmake ../ -DCMAKE_INSTALL_PREFIX="/Users/PATH_TO_LIB/mpilib20_library"

If no build directory is specified, will build in:

ROOT/BUILD_DIR/mpilib20_library

After configuring CMake, MPILib20 can be built and installed with:

make install

Check Compilation

A simple test code is present in ROOT/test/init to check building and linking. To run, modify init/CMakeLists.txt ROOT to where the library has been installed, then in the terminal:

mkdir build && cd build
make
mpirun -np 2 ./test.exe

Bugs/To Dos

General TODOS

• Update CMake to reflect changes
• Add ubnit testing framework to CMake
• Add make docs with FORD to cmake
• Document all existing routines with FORD
• Write wrappers for routines listed below
• Provide API for mpi_f08 and mpi bindings
• Allow OO and free-function API => the OO functions just wrap the free functions
• Start on serial wrappers
• The mpi types we're writing should probably be protected, such thay the data can be read but only modified by methods of the type:
  • Add get and set
• Start adding asserts into routines

Future

• Implement communicator splitting
• Implement cartesian comms splitting

TODOS(Alex)

• Set up MPI unt test framework and write an example unit test
• Take allgatherv and allscatterv routines that I wrote in the past. Reimplement here, but do some more cleanly

TODOS(Max)

• higher-level routines to perform send and receives
• Other things he'd like to take

Directory structure

errors_warnings asserts.F90 errors_warnings.f90 constants May not need routines: each type and wrapped routine mpi_bindings: Wrappers for when mpif08 is not available

unit_tests Only test via the OO. That way we test the OO API and the underlying wrappers

Routines to Wrap

mpi_abort mpi_barrier mpi_wait mpi_allreduce: Needs to be overloaded for integer, sp, dp, logical, character scalars and vectors mpi_bcast
mpi_send mpi_recv mpi_irecv mpi_scatter and v mpi_gather and v mpi_allgather and v mpi_allscatter and v

comm splitting stuff Probably more

CMake

• CMake still installs to .../include/modules rather than .../include
• FFLAGS option should replace the defaults, not append them
• All Cmake options require documenting for the user
• Intel requires testing
• WARNINGS_AS_ERRORS = True fails for GCC
• Add doxygen support

Meson

• meson needs fixing and extending