! helloWorldF.f90

        program main
        include "mpif.h"

        integer myid
        integer ierr

        call MPI_INIT(ierr)
        call MPI_COMM_RANK(MPI_COMM_WORLD, myid, ierr)
        print *, 'Hello from ', myid

        call MPI_FINALIZE(ierr)

        end program

! Cray SV1 version:

! f90 helloWorldF.f90

! mpirun -np 4 a.out
! Hello from 0.
! Hello from 2.
! Hello from 1.
! Hello from 3.

! mpirun -np 16 a.out
! Hello from 0.
! Hello from 1.
! Hello from 2.
! Hello from 3.
! Hello from 4.
! Hello from 5.
! Hello from 6.
! Hello from 8.
! Hello from 9.
! Hello from 10.
! Hello from 7.
! Hello from 11.
! Hello from 13.
! Hello from 14.
! Hello from 15.