int ub = vars[i].getUB();
for (j = vars[i].getLB(); j <= ub; j = vars[i].nextValue(j)) {
layerIter = layer.get(i).iterator();
while (layerIter.hasNext()) {
k = layerIter.next();
succ.clear();
pi.delta(k, j, succ);
if (!succ.isEmpty()) {
TIntIterator it = succ.iterator();
for (; it.hasNext(); )
layer.get(i + 1).add(it.next());