On Fri, Mar 21, 2014 at 10:37 AM, [email protected] <[email protected]>wrote:
> Hi > > Is the question below out of that the vertice id has been changed in > induced.subgraph()? > If I understand this question correctly, then yes. It creates another graph, internal vertex ids change. G. > If I want to generate a subgraph which contains all the vertices and just > delete the edges to make the vertices, which were meant to be delete, to be > isolate? > > best > Xueming > > ------------------------------ > [email protected] > > *发件人：* [email protected] > *发送时间：* 2014-03-21 22:00 > *收件人：* igraph-help <[email protected]> > *主题：* Question about the functions induced.subgraph() and clusters() > > Hi! > > It is known to us that the maximal weakly connected component of a > connected nework is itself. Just like the code below shows that the > elements of Siz_wcc never change. > > ga <- erdos.renyi.game(1000, 1500, type = "gnm", directed=TRUE); > Siz_wcc <- rep(0,10) > for(i in 1:10) > { > wcca <- clusters(ga, mode="weak") > largest_wcc_va <- which(wcca$membership == > which.max(wcca$csize)) > Siz_wcc[i] <- length(largest_wcc_va) > ga <- induced.subgraph(ga, largest_wcc_va, > impl="copy_and_delete") > } > > Siz_wcc > [1] 936 936 936 936 936 936 936 936 936 936 > > Given two networks ga and gb, if network ga is exactly the same with > network gb, then the elements in Siz_wcca and Siz_wccb are also expected to > be invariant. But Siz_wcca and Siz_wccb decrease to 1 in the end. How could > this happen? > > gb <- erdos.renyi.game(1000, 1500, type = "gnm", directed=TRUE); > ga <- gb > Siz_wcca <- rep(0,10) > Siz_wccb <- rep(0,10) > for(i in 1:10) > { > wcca <- clusters(ga, mode="weak") > largest_wcc_va <- which(wcca$membership == > which.max(wcca$csize)) > Siz_wcca[i] <- length(largest_wcc_va) > gb <- induced.subgraph(gb, largest_wcc_va, > impl="copy_and_delete") > > wccb <- clusters(gb, mode="weak") > largest_wcc_vb <- which(wccb$membership == > which.max(wccb$csize)) > Siz_wccb[i] <- length(largest_wcc_vb) > ga <- induced.subgraph(ga, largest_wcc_vb, > impl="copy_and_delete") > } > > Siz_wcca > [1] 933 854 756 615 331 3 1 1 1 1 > > Siz_wccb > [1] 933 845 722 521 46 1 1 1 1 1 > > best > Xueming > > ------------------------------ > [email protected] > > _______________________________________________ > igraph-help mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/igraph-help > >
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