private void buildSCC() {
digraph.removeNode(n2);
digraph.removeNode(n2 + 1);
digraph.addNode(n2);
digraph.addNode(n2 + 1);
// TODO CHECK THIS PART
for (int i = 0; i < n; i++) {
if (free.get(i)) {
digraph.addArc(n2, i);
} else {
digraph.addArc(i, n2);
}
}
for (int i = n; i < n2; i++) {
if (free.get(i)) {
digraph.addArc(i, n2 + 1);
} else {
digraph.addArc(n2 + 1, i);
}
}
SCCfinder.findAllSCC();
nodeSCC = SCCfinder.getNodesSCC();
digraph.removeNode(n2);
digraph.removeNode(n2 + 1);
}
@Override
public void propagate(int evtmask) throws ContradictionException {
if (PropagatorEventType.isFullPropagation(evtmask)) {
if (n2 < n + vars[n].getLB()) {
fails(); // TODO: could be more precise, for explanation purpose
}
buildDigraph();
}
digraph.removeNode(n2);
digraph.removeNode(n2 + 1);
free.clear();
for (int i = 0; i < n; i++) {
if (digraph.getPredOf(i).size() == 0) {
free.set(i);
}
}
for (int i = n; i < n2; i++) {
if (digraph.getSuccOf(i).size() == 0) {
free.set(i);
}
}
int card = repairMatching();
vars[n].updateUpperBound(card, this);
if (vars[n].getLB() == card) {
filter();
}
for (int i = 0; i < idms.length; i++) {
idms[i].unfreeze();
}
}
private void tryToMatch(int i) throws ContradictionException {
int mate = augmentPath_BFS(i);
if (mate != -1) {
free.clear(mate);
free.clear(i);
int tmp = mate;
while (tmp != i) {
digraph.removeArc(father[tmp], tmp);
digraph.addArc(tmp, father[tmp]);
tmp = father[tmp];
}
}
}
private void buildDigraph() {
for (int i = 0; i < n2; i++) {
digraph.getSuccOf(i).clear();
digraph.getPredOf(i).clear();
}
free.set(0, n2);
int j, k, ub;
IntVar v;
for (int i = 0; i < n2 + 2; i++) {
digraph.removeNode(i);
}
for (int i = 0; i < n; i++) {
v = vars[i];
ub = v.getUB();
for (k = v.getLB(); k <= ub; k = v.nextValue(k)) {
j = map.get(k);
digraph.addArc(i, j);
}
}
}
private int repairMatching() throws ContradictionException {
for (int i = free.nextSetBit(0); i >= 0 && i < n; i = free.nextSetBit(i + 1)) {
tryToMatch(i);
}
int card = 0;
for (int i = 0; i < n; i++) {
if (digraph.getPredOf(i).size() > 0) {
card++;
}
}
return card;
}
private int augmentPath_BFS(int root) {
in.clear();
int indexFirst = 0, indexLast = 0;
fifo[indexLast++] = root;
int x;
ISetIterator succs;
while (indexFirst != indexLast) {
x = fifo[indexFirst++];
succs = digraph.getSuccOf(x).iterator();
while (succs.hasNext()) {
int y = succs.nextInt();
if (!in.get(y)) {
father[y] = x;
fifo[indexLast++] = y;
in.set(y);
if (free.get(y)) {
return y;
}
}
}
}
return -1;
}
private void filter() throws ContradictionException {
buildSCC();
int j, ub;
IntVar v;
for (int i = 0; i < n; i++) {
v = vars[i];
ub = v.getUB();
for (int k = v.getLB(); k <= ub; k = v.nextValue(k)) {
j = map.get(k);
if (nodeSCC[i] != nodeSCC[j]) {
if (digraph.getPredOf(i).contains(j)) {
v.instantiateTo(k, this);
} else {
v.removeValue(k, this);
digraph.removeArc(i, j);
}
}
}
if (!v.hasEnumeratedDomain()) {
ub = v.getUB();
for (int k = v.getLB(); k <= ub; k = v.nextValue(k)) {
j = map.get(k);
if (digraph.arcExists(i, j) || digraph.arcExists(j, i)) {
break;
} else {
v.removeValue(k, this);
}
}
int lb = v.getLB();
for (int k = ub; k >= lb; k = v.previousValue(k)) {
j = map.get(k);
if (digraph.arcExists(i, j) || digraph.arcExists(j, i)) {
break;
} else {
v.removeValue(k, this);
}
}
}
}
}
