Custom MPI Wrapper for Fortran

Welcome to the Custom MPI Wrapper project! This repository contains a Fortran-based implementation of MPI wrappers that bind directly to native MPI library routines using ISO_C_BINDING. The goal is to eliminate intermediate C wrappers and call MPI functions directly from Fortran.

This project currently supports MPI routines such as MPI_Init, MPI_Bcast, MPI_Reduce, MPI_Comm_split_type, MPI_Recv, MPI_Ssend, MPI_Waitall, and more. In addition, the repository provides several tests to verify the correctness of these custom wrappers.

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Prerequisites

• Fortran Compiler:
  You can use LFortran, gfortran, or any standard Fortran compiler.

• MPI Library:
  This project supports OpenMPI and MPICH. Install the desired MPI library along with its development headers.

• Conda Environment (Optional):
  It is recommended to create separate conda environments for MPICH and OpenMPI:

  • For MPICH:

    conda create -n mpich_env mpich=4.3.0
    conda activate mpich_env

  • For OpenMPI:

    conda create -n openmpi_env openmpi=5.0.6
    conda activate openmpi_env

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Running Tests

The repository contains a collection of standalone tests located in the tests/ directory. These tests validate the functionality of the custom MPI wrappers.

Running All Standalone Tests

To execute all standalone tests, navigate to the tests/ directory and run:

cd tests/
FC='lfortran' ./run_tests.sh

Running a Specific Standalone Test

If you want to run a single test (for example, testFilename.f90), execute:

cd tests/
FC='lfortran' ./run_tests.sh testFilename.f90

Running the pot3d Test

To build and run the pot3d test, navigate to the tests/pot3d/ directory.

• For Lfortran run:

cd tests/pot3d/
FC='lfortran' ./build_and_run_lfortran.sh

• For GFortran run:

cd tests/pot3d/
FC='gfortran' ./build_and_run_gfortran.sh

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Customizing Compiler Flags

You can pass custom flags to your Fortran compiler using the FC environment variable. For example, to compile with optimization flags using gfortran, run:

FC='gfortran -O3' ./run_tests.sh

This enables you to tailor the compilation process to your needs.