Update FCI.py for fixing isNoncollider

Editing isNoncollider() for FCI Algo;
Fixing Bug:
If sep_set does not contain certain node combination, this will led to a KeyError. With this fix, None will automatically set by the get func. Also get_node_map() will only called once to check sep_set

Signed-off-by: Sven Pieper <[email protected]>

Author: svenpieper

causallearn/search/ConstraintBased/FCI.py

@@ -320,7 +320,8 @@ def rulesR1R2cycle(graph: Graph, bk: BackgroundKnowledge | None, changeFlag: boo
 
 def isNoncollider(graph: Graph, sep_sets: Dict[Tuple[int, int], Set[int]], node_i: Node, node_j: Node,
                   node_k: Node) -> bool:
-    sep_set = sep_sets[(graph.get_node_map()[node_i], graph.get_node_map()[node_k])]
+    node_map = graph.get_node_map()
+    sep_set = sep_sets.get((node_map[node_i], node_map[node_k]))
     return sep_set is not None and sep_set.__contains__(graph.get_node_map()[node_j])