Hi
Is the question below out of that the vertice id has been changed in
induced.subgraph()?
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
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
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