MPI installation on ubuntu server 12.04

Type a command below

 $ sudo aptitude install openmpi-bin libopenmpi-dev

and after installation, check whether it has correctly done.

#include <mpi/mpi.h>

int main( int argc, char *argv[] )
{
    int myid, numprocs;
    volatile int i;
    MPI_Init( &argc, &argv );
    MPI_Comm_size( MPI_COMM_WORLD, &numprocs );
    MPI_Comm_rank( MPI_COMM_WORLD, &myid );

    printf( "Hello World! %d\n", myid );
    for ( i = 0; i < 100000000; i++ );
    MPI_Finalize();
    
    return 0;
}

save the above as mpihello.c, compile and run it like below

 $ mpicc mpihello.c -W -Wall
 $ mpirun -np 4 ./a.out
Hello World! 2
Hello World! 3
Hello World! 1
Hello World! 0