Note that in the scheme shown in FIG 17, it is assumed that all variable nodes are updated parallely at {HEAD ~ the same time} which is {TAIL ~ a parallel scheduling} 
is
Note that in the scheme shown in FIG 17 , it is assumed that all variable nodes are updated parallely at { HEAD ~ the same time } which is { TAIL ~ a parallel scheduling }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL