/**
* Performs step C of the algorithm, as indicated on page xxx of CPS, with the modification that
* X--W--Y is oriented as X-->W<--Y if W is *determined by* the sepset of (X, Y), rather than W
* just being *in* the sepset of (X, Y).
*/
public static void pcdOrientC(
SepsetMap set, IndependenceTest test, Knowledge knowledge, Graph graph) {
TetradLogger.getInstance().log("info", "Staring Collider Orientation:");
List<Node> nodes = graph.getNodes();
for (Node y : nodes) {
List<Node> adjacentNodes = graph.getAdjacentNodes(y);
if (adjacentNodes.size() < 2) {
continue;
}
ChoiceGenerator cg = new ChoiceGenerator(adjacentNodes.size(), 2);
int[] combination;
while ((combination = cg.next()) != null) {
Node x = adjacentNodes.get(combination[0]);
Node z = adjacentNodes.get(combination[1]);
// Skip triples that are shielded.
if (graph.isAdjacentTo(x, z)) {
continue;
}
List<Node> sepset = set.get(x, z);
if (sepset == null) {
continue;
}
List<Node> augmentedSet = new LinkedList<Node>(sepset);
augmentedSet.add(y);
if (test.determines(sepset, y)) {
continue;
}
//
if (!test.splitDetermines(sepset, x, z) && test.splitDetermines(augmentedSet, x, z)) {
continue;
}
if (!isArrowpointAllowed(x, y, knowledge) || !isArrowpointAllowed(z, y, knowledge)) {
continue;
}
graph.setEndpoint(x, y, Endpoint.ARROW);
graph.setEndpoint(z, y, Endpoint.ARROW);
TetradLogger.getInstance()
.log("colliderOriented", SearchLogUtils.colliderOrientedMsg(x, y, z));
}
}
TetradLogger.getInstance().log("info", "Finishing Collider Orientation.");
}
