[igraph] Selecting vertices for centrality analysis in R

[Jorge Gil]

Hi all,

I'm trying to run centrality analysis on a graph in R but only want to 
get the results for a selection of vertices. The graph has edge weight 
attributes and when I run the betweenness analysis for all vertices it 
works, but for a selection of them it crashes. I attach a sample of this 
data to this email.

It might be a problem with the way I'm selecting vertices for analysis. 
The selection of vertices is dynamic and changes in a loop, and it is 
stored in a vector (lo) containing the id name (character) of the vertices.
The code I'm running is:

    bet<-betweenness(lg,v=V(lg)[name %in% 
lo$road_id],directed=F,normalized=T,weights=E(lg)$metric)


If I run the above without weights it never crashes, nor does it crash 
if I calculate closeness.

    betN<-betweenness(lg,v=V(lg)[name %in% 
lo$road_id],directed=F,normalized=T)


Of course it could also be a problem with the weights, but the values 
are all positive >0, and if I run the analysis for all vertices it 
doesn't crash either.

betN<-betweenness(lg,directed=F,normalized=T,weights=E(lg)$metric)


So I assume I'm doing something wrong with the vertex selection.

As a final point: I would like the weight to be selected dynamically so 
that I can repeat the analysis in a loop for different weights. How can 
I refer to the Edge attributes dynamically, using an index for example.


Thank you in advance,
Jorge

--
Jorge Gil
PhD Candidate

TU Delft / Faculty of Architecture
Department of Urbanism
Chair of Spatial Planning and Strategy

Julianalaan 134
2628 BL Delft
P.O. Box 5043
2600 GA Delft
The Netherlands

www.tudelft.nl

roadnet.RData
Description: Binary data