Re: [igraph] Selecting vertices for centrality analysis in R

[Gábor Csárdi]

On Tue, Dec 18, 2012 at 7:47 AM, Jorge Gil <address@hidden> wrote:

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But maybe providing a set of vertices for origin - destination pairs, to calculate only the routes between those, would be very useful. This could cut time dramatically.

You can relatively easily do this "by hand", i.e. using get.all.shortest.paths(). But I see the point, so feel free to submit a bug report for this at https://bugs.launchpad.net/igraph. Thanks.

 

In the networkX pacakge for python there's a version of betweenness centrality where we can set a random percentage of vertices to use. I did some tests and in my networks using 10% of the routes the result has a .999 R2 to the full calculation. The final values are different, but the ranking of nodes is exactly the same.

.999 is a bit surprising. Btw. what exactly is 10% of the routes? You select 10% of the vertices and then calculate shortest paths from these to all vertices?

 

Adding the selection of target vertices to the closeness or degree functions would also be useful, allowing to qualify centrality results with regards to specific sub-groups.

Please add a bug report for these as well, at https://bugs.launchpad.net/igraph, if you really want to have them in igraph. Thanks!

G.

 

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