PC algorithm logic

[kenneth-lee-ch]

In the causal-learn/causallearn/utils/PCUtils/SkeletonDiscovery.py, why does it need to add sepsets to cp.sepset at lines 123-124? If the p-value return at line 101 is not greater than alpha for all S in line 100, doesn't that mean you force an empty set to be a separating set?

[kunwuz]

Yes, and it is consistent with the pseudo-code of PC, where an empty set could be a separating set.

[kenneth-lee-ch]

I mean you will infer d-separation with respect to an empty set regardless of the test result.

[kunwuz]

Thanks for the explanation. @zhi-yi-huang tried to fix this issue in #161 (thanks so much!). Please let us know if there are any questions.