I compiled and ran the subgraph.cpp which comes with the library (in example directory). I got results which are different from subgraph.expected. Here are my outputs: G0: 0 --> 1 1 --> 2 3 2 --> 5 3 --> 4 --> 1 5 5 --> 3 0(0,1) 1(1,2) 2(1,3) 6(2,5) 3(4,1) 4(4,5) 5(5,3) G1: 0 --> 2 1 --> 2 2 --> 6(0,2) 4(1,2) G2: 0 --> 1 1 --> 0(0,1) I also have a question: in the output, the indices for the both subgraphs start from 0 which makes sense to me. However, why don't the edge index start from 0, as well? It looks like the edge index matches their corresponding indices in the main graph. I don't think it makes sense. Moreover, it creates problems when I try to attach properties to edges because the maximum edge index for a subgraph is larger than the number of edges in that subgraph. Thanks. Hailin