flyingdoog / PGExplainer

Parameterized Explainer for Graph Neural Network
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PGexplainer is weak against graphs with mean degree greater than 1000 #13

Open ErikJhones opened 1 year ago

ErikJhones commented 1 year ago

Hello. How are you? I'm investigating PGexplainer and I noticed that it is incredibly weak at explaining graphs with nodes with more than 1000 neighbors. An example is the bitcoin-alpha and -otc dataset. PGexplainer (with 3hop) does not achieve 1% explanation accuracy. For 1hop (average degree 17), PGexplainer achieves ~83% accuracy. Why does this occur?

Another point is the explanation time which is said to outperform GNNexplainer, however, for cases with nodes with degree greater than 1000, PGexplainer is much slower than GNNexplainer. Why does this occur?