!********************************************************************
! program    : mpi_samp2.f90
! programmer : makoto nakajima
! description: hello, world! with conditional if statement.
! date       : april 25, 2006
!********************************************************************
program main
	implicit none     !prohibit implicit declaration of variables
	include 'mpif.h'  !include mpi library

	!******* variables related mpi *******
	integer:: ierror !return error message from mpi subroutines
	integer:: id     !identification number of each processor
	integer:: nproc  !total number of processors

	!******* other variable declaration *******
	integer:: idsays !determines who says hello

	!******* initialization *******
	!initialization of mpi environment
	call mpi_init(ierror)

	!obtain id for each node
	call mpi_comm_rank(mpi_comm_world, id, ierror)

	!returns the number of nodes
	call mpi_comm_size(mpi_comm_world, nproc, ierror)

	!******* main part of program *******
	idsays=4              !node 4 says hello ad others don't
	if (id==idsays) then  !different message between idyes and others.
		print *, 'hello, world! i am node ',id
	else
		print *, 'i am node ',id,'. i wish i could say hello...'
	end if

	!******* finalize mpi environment *******
	call mpi_finalize(ierror)

end program main