Writing MPI programs I

First program with MPI ( hello.c). Write the following code and study the response.

    1 #include "mpi.h"
    2 #include <stdio.h>
    3  
    4 int main( argc, argv )
    5 int argc;
    6 char **argv;
    7 {
    8     MPI_Init( &argc, &argv );
    9     printf( "Hello world\n" );
   10     MPI_Finalize();
   11     return 0;
   12 }

• #include "mpi.h"
  

  provides basic MPI definitions and types.

• MPI_Init
  

  starts MPI.

• MPI_Finalize
  

  exits MPI.
• Note that all non-MPI routines are local; thus the

  printf
  

  run on each process.

mpicc -o hello hello.c
mpirun -np 2 hello