Thanks again for the clarification! I think what actually happens is that the neighbours of a vertex are counted as the degree of that vertex (which is not the same thing for multigraphs).
Do you think a patch that converts directed graphs to undirected simple graphs before computing the local clustering coefficient would be appropriate here? On 7 December 2015 at 13:16, Gábor Csárdi <[email protected]> wrote: > I am not sure if it is defined. I guess this is just a case when the > behavior is not defined for multi-graphs. > > Gabor > > On Mon, Dec 7, 2015 at 12:14 PM, Szabolcs Horvát <[email protected]> wrote: >> Thank you for the explanation. >> >> Could you elaborate a bit on how igraph defines the local clustering >> coefficient when multiple (parallel) edges are present? >> >> On 7 December 2015 at 12:56, Gábor Csárdi <[email protected]> wrote: >>> It's because of the multiple edges in the first graph. I.e.: >>> >>>> transitivity(as.undirected(g, mode = "each"),"local") >>> [1] 0.3333333 0.3333333 1.0000000 >>> >>> Gabor >>> >>> On Mon, Dec 7, 2015 at 10:05 AM, Szabolcs Horvát <[email protected]> wrote: >>>> Hello, >>>> >>>> What precisely does igraph_transitivity_undirected() compute for >>>> directed graphs? >>>> >>>> The C documentation states that >>>> >>>> "Directed graphs are considered as undirected ones." >>>> >>>> but this is not exactly the case. >>>> >>>> With an example using the R interface (for simplicity), >>>> >>>>> g<-make_graph(c(1,2, 2,1, 2,3, 3,1)) >>>>> transitivity(g,"local") >>>> [1] 0.3333333 0.3333333 1.0000000 >>>> >>>>> transitivity(as.undirected(g),"local") >>>> [1] 1 1 1 >>>> >>>> Can someone clarify what precisely is computed in the directed case? >>>> >>>> Szabolcs >>>> >>>> _______________________________________________ >>>> igraph-help mailing list >>>> [email protected] >>>> https://lists.nongnu.org/mailman/listinfo/igraph-help >>> >>> _______________________________________________ >>> igraph-help mailing list >>> [email protected] >>> https://lists.nongnu.org/mailman/listinfo/igraph-help >> >> _______________________________________________ >> igraph-help mailing list >> [email protected] >> https://lists.nongnu.org/mailman/listinfo/igraph-help > > _______________________________________________ > igraph-help mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/igraph-help _______________________________________________ igraph-help mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/igraph-help
