public double tryChangeSource(double temp, double currentEnergy) {
PEdge<V, E> fakeEdge = sourceFakeEdges.get(random.nextInt(sourceFakeEdges.size()));
PNode<V, E> child = fakeEdge.to;
int oldIndex = fakeEdge.from.getChildren().indexOf(fakeEdge);
child.removeParent(fakeEdge);
fakeEdge.from.removeChild(fakeEdge);
PEdge<V, E> fakeEdge2;
int fakeEdge2Swap = -1;
if (fakeEdge.from.isRoot || random.nextDouble() < 0.4) { // try attaching it somewhere else
PNode<V, E> parent;
if (Math.random() < 0.5
|| nodesWithSeveralChildrenScaled.size() == 0) { // try some completely random node
parent = nodes.get(random.nextInt(nodes.size()));
} else {
parent =
nodesWithSeveralChildrenScaled.get(
random.nextInt(nodesWithSeveralChildrenScaled.size()));
}
fakeEdge2 = new PEdge<V, E>(parent, child);
parent.addChild(fakeEdge2);
if (parent.getChildren().size() > 1) {
fakeEdge2Swap = random.nextInt(parent.getChildren().size() - 1);
parent.swapChildren(parent.getChildren().size() - 1, fakeEdge2Swap);
}
child.addParent(fakeEdge2);
} else { // try attaching it back to root.
fakeEdge2 = new PEdge<V, E>(root, child);
root.addChild(fakeEdge2);
if (root.getChildren().size() > 1) {
fakeEdge2Swap = random.nextInt(root.getChildren().size() - 1);
root.swapChildren(root.getChildren().size() - 1, fakeEdge2Swap);
}
child.addParent(fakeEdge2);
}
if (!graphHasCycle(fakeEdge2.to)) {
double newEnergy = getEnergy();
if (acceptChange(currentEnergy, newEnergy, temp)) {
sourceFakeEdges.remove(fakeEdge);
sourceFakeEdges.add(fakeEdge2);
return newEnergy;
}
}
fakeEdge2.from.removeChild(fakeEdge2);
child.removeParent(fakeEdge2);
if (fakeEdge2Swap != -1) {
PEdge<V, E> e = fakeEdge2.from.getChildren().get(fakeEdge2.from.getChildren().size() - 1);
fakeEdge2.from.getChildren().remove(fakeEdge2.from.getChildren().size() - 1);
fakeEdge2.from.getChildren().add(fakeEdge2Swap, e);
}
// fakeEdge.from.addChild(fakeEdge);
fakeEdge.from.getChildren().add(oldIndex, fakeEdge);
child.addParent(fakeEdge);
return currentEnergy;
}
public double tryAddFakeEdge(double temp, double currentEnergy) {
// it's sufficient to only add fake edges from leaves to nodes with multiple parents
if (nodesWithoutChildren.size() > 0 && nodesWithSeveralParents.size() > 0) {
PNode<V, E> from = nodesWithoutChildren.get(random.nextInt(nodesWithoutChildren.size()));
PNode<V, E> to = nodesWithSeveralParents.get(random.nextInt(nodesWithSeveralParents.size()));
PEdge<V, E> fakeEdge = new PEdge<V, E>(from, to);
from.addChild(fakeEdge);
to.addParent(fakeEdge);
if (!graphHasCycle(to)) {
double newEnergy = getEnergy();
if (acceptChange(currentEnergy, newEnergy, temp)) {
fakeEdges.add(fakeEdge);
return newEnergy;
}
}
// otherwise undo changes
from.removeChild(fakeEdge);
to.removeParent(fakeEdge);
return currentEnergy;
}
return currentEnergy;
}