Writing MPI programs

First program with MPI (hello.c)

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

int main( argc, argv )
int argc;
char **argv;
{
MPI_Init( &argc, &argv );
printf( "Hello world\n" );
MPI_Finalize();
return 0;
}

• #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.