[MPI] Solution 1 : Hello World

This material is part of the course Practical Introduction to Parallel Programming and meant for educational purposes only.

Task

Implement a small MPI program that prints the total number of processes and the rank of the current process.

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Question 1: Hello World

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

int main()
{
  int  proc_count;
  int  my_rank;

  /* Initialize the MPI library. */

  MPI_Init ( NULL, NULL );

  /* Get the number of processes and get the rank of the
   * current process. */

  MPI_Comm_size ( MPI_COMM_WORLD, &proc_count );
  MPI_Comm_rank ( MPI_COMM_WORLD, &my_rank );

  /* Print a message. */

  printf ( "Hello world from process %d out of %d.\n",
           my_rank, proc_count );

  /* Close the MPI library. */

  MPI_Finalize ();

  return 0;
}

Question 2: Number of MPI processes

Specify the number of MPI processes (1-64) that should be used for running your program (mpirun -np <nproc>)

Question 3: Command Line Argument

Specify the command line arguments that should be passed to your program when it is run. Arguments must be given in quotes and separated by commas. Leave this filed empty if you do not want to specify command line arguments.

Example: "1","int","arg=2" is interpreted as three arguments 1, int, and arg=2.

Author(s)	Erik-Jan Lingen, Matthias Möller
Deadline	Keine Frist
Submission limit	No limitation

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