{HEAD ~ The process} 52 wherein each of the parallel processing elements generates {TAIL ~ an intermediate result} for its respective partition 
{ HEAD ~ The process } 52 wherein each of the parallel processing elements generates { TAIL ~ an intermediate result } for its respective partition
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH