call MPI_Init(ierr)
world = MPI_COMM_WORLD
call MPI_Comm_size(world,numprocs,ierr)
MPI_Comm_rank(world,myid,ierr)
randServer = numprocs-1


  if (myid .eq. 0) then
	print *,"Enter epsilon"
	read(*,*)epsilon
  end if

call MPI_Comm_group( world, world_group, ierr )	                   !get group of everyone  
ranks(0) = randServer		                                   ! exclude the last   
call MPI_Group_excl( world_group, 1, ranks, worker_group, ierr )   ! get new group
call MPI_Comm_create( world, worker_group, workers, ierr)          ! get new comm 


if (myid .eq. randServer) then	! I am the rand server 
	call MPI_Recv(request, 1, MPI_INT, MPI_ANY_SOURCE, 
                      NEED_NUMBERS, world, mesgStatus, ierr)
	do while (request > 0)
		do i=0,CHUNKSIZE
		randNums(i) = rand()
		end do
		call MPI_Send(randNums, CHUNKSIZE, MPI_INT, 
                              mesgStatus(MPI_SOURCE), 
			      RANDOM_NUMBERS, world, ierr)
                call MPI_Recv(request, 1, MPI_INT, 
                              MPI_ANY_SOURCE, NEED_NUMBERS,
	                      world, mesgStatus, ierr)
        end do
	
else			! I am a worker process 
request = 1
done = 0
in = 0
out = 0
	
call MPI_Send( request, 1, MPI_INT, randServer, NEED_NUMBERS, world, ierr )
	! request a string of random numbers 
	
call MPI_Comm_rank( workers, workerNum, ierr )
	do while (.not.done)
	request = 1
	call MPI_Recv( randNums, CHUNKSIZE, MPI_INT, randServer, RANDOM_NUMBER, world, 
                       mesgStatus )
	   
	do i=1, CHUNKSIZE,2
	

	        x =  (randNums(i)/max) * 2 - 1
		y =  (randNums(i+1)/max) * 2 - 1

		if (x*x + y*y .lt 1.0) then
		   in=in+1
		else
		   out=out+1
                end if
        end do
	 
	call MPI_Reduce(in, totalin, 1, MPI_INT, MPI_SUM, 0, workers)
	
	MPI_Reduce(out, totalout, 1, MPI_INT, MPI_SUM, 0, workers)  ! count total of outs 

	if (myid .eq. 0) then
	    calculatedPi = (4.0*totalin)/(totalin + totalout)
            error = abs( calculatedPi-3.141592653589793238462643)
            if ((error .lt. epsilon) .or. (totalin+totalout).gt.1000000000)then 
                    done=.true.
                    request = 0
            else
                    done=.false.
                    request = 1
            end if
	    print *,calculatedPi
	    call MPI_Send( request, 1, MPI_INT, randServer, 
                           NEED_NUMBERS,
			   world, ierr )
	    call MPI_Bcast( done, 1, MPI_INT, 0, workers )
	else
	
	    call MPI_Bcast( done, 1, MPI_INT, 0, workers )
	    if (.not.done) then
		call MPI_Send( request, 1, MPI_INT, randServer, NEED_NUMBERS,
			 world )
	    end if
	end if
	
if (myid .eq. 0)print *, "npoints:", totalin+totalout," in:" totalin, , "out:",totalout
	
call MPI_Finalize()