I want to run the program with my computer which has two cores and I want to use both cores, here is the simple testing program:

/*The Parallel Hello World Program*/
#include <stdio.h>
#include <mpi.h>

int main(int argc, char **argv)
int node;

MPI_Comm_rank(MPI_COMM_WORLD, &node);

printf("Hello World from Node %d\n",node);

return 0;

I use mpicc to compile in ubuntu and I run it trying to use commands "mpirun -np 2 ./try.exe" and "mpirun ./try.exe" but some error message comes out:

mpiexec_ubuntu: cannot connect to local mpd (/tmp/mpd2.console_shsh); possible causes:
1. no mpd is running on this host
2. an mpd is running but was started without a "console" (-n option)
In case 1, you can start an mpd on this host with:
mpd &
and you will be able to run jobs just on this host.
For more details on starting mpds on a set of hosts, see
the MPICH2 Installation Guide.

What do it means? can I use mpirun in ubuntu?