“…For this application, smoothed V-cycles with distance-one aggregation perform better than cycles with distance-two aggregation. Table 6.10 compares one-level relaxation (with two relexations on the fine level per iteration), twolevel A-AM aggregation (with two relaxations on the coarse level; this is essentially equivalent to the aggregation/disaggregation methods of [7,8,9,10,11,12,13,14]), and unsmoothed, multilevel A-AM (which is the same as MAA in [6], and similar to the multilevel aggregation methods of [4,5]). It can be observed that traditional twolevel and multilevel aggregation methods hardly manage to accelerate convergence for this problem.…”