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This article is part of the HOWTO series.
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This is a work in progress.

Essentially I want to put some very simple "hello world" type of programs here, so people with absolutely no clue of parallel computing can start from here and write/compile/run his/her first parallel program!

Example of a MPI - helloWorld

#include <stdio.h>
#include <mpi.h>

int main(int argc, char *argv[]) {
    int rank, size;
    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    printf("Hello, world! I am %d of %d \n", rank, size);
    return 0;

A rank identifies a "execution unit".
Size identifies the amount of "execution units" the mpi application has.

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Last modified: Fri, 08 Aug 2008 10:55:00 +0000 Hits: 9,768