MPI: Concurrent File I/O for by Multiple Processes

In this tutorial, we’ll explore an MPI (Message Passing Interface) program using mpi4py to demonstrate how multiple processors can collectively write to and read from a shared file.

Code

from mpi4py import MPI

    comm = MPI.COMM_WORLD
    rank = comm.Get_rank()
    size = comm.Get_size()
    # Define the file name
    filename = "output.txt"
    # Open the file in append mode and write a message from each processor
    with open(filename, "a") as file:
        file.write(f"Hello from processor {rank} of {size}\n")
    # Synchronize all processors before reading the file
    comm.Barrier()
    # Now let only one processor (e.g., rank 0) read and display the file content
    if rank == 0:
        # Open the file in read mode
        with open(filename, "r") as file:
            # Read and display the file content
            print("File contents:")
            print(file.read())

Code Explanation