On Mon, Dec 7, 2015 at 1:28 PM, Szabolcs Horvát <[email protected]> wrote: [...] > Do you think a patch that converts directed graphs to undirected > simple graphs before computing the local clustering coefficient would > be appropriate here?
Converting the whole graph is not a good solution, because that is O(n+m), and local transitivity is O(1). Converting the graph locally, at the queried vertex, is maybe a better idea, but also harder to implement. So we might as well modify the local transitivity code. Gabor > 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 _______________________________________________ igraph-help mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/igraph-help
