APBRmetrics

[spurusho]

Hello,

I am calculating 'Betweenness' of a large network using R. Currently, I
have the node-node information (City1-City2) in an excel file, present
in two columns where column A has City1 and column B has City2 that
city1 is connected to. These are the steps that I go through to
calculate betweenness of my network.

a) Convert the City1-City2 (text) into Number1-Number2 in the excel file
where every unique city has a unique number.
b) Paste all the city-city information separated by comma into c(...) in
the R GUI to obtain the corresponding vectors. As you can imagine this
copy-paste operation takes a long time. Example: c(1,3,1,5,2,4,2,5).
Just fyi, I have a text file that contains all nodes separated by comma
based on the appropriate link information.
c) Then, I create a graph file with the above vector.
d) I use the graph file to calculate betweenness of my network.

I am sure there must be a better, more efficient way to calculate
betweenness. Ideally, I would like to just have the City1 - City2 (link)
information in two columns in an excel file and calculate the
betweenness from that file directly.

Please provide an optimal solution for this problem. I appreciate your
time and help.

Thanks,
Senthil
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Ferrari Modulo specifications

[Ryan J. Parker]

Although some of us here are familiar with R, I'd strongly suggest you try the R mailing lists: http://www.r-project.org/mail.html.

I'm sure they will help give you the "optimal solution" you seek.

[Ed Küpfer]

I'm willing to help out (to the extent that I can), but I don't understand your betweenness and network termilnology. Can you spell out your data and your goal with more detail?
_________________
ed

[dsparks]

Though I have not used it, there is apparently a function for calculating betweenness in the package igraph: http://cneurocvs.rmki.kfki.hu/igraph/doc/R/betweenness.html

It looks pretty straightforward. The SNA package, which I have used, also has a betweenness() function. http://cran.r-project.org/web/packages/sna/index.html
_________________
David

http://arbitrarian.wordpress.com

[spurusho]

I am talking to the experts in the CRAN project. The problem with the SNA package that I use in R is that the input has to be an array or an adjacency matrix and I am talking about 50,000 nodes and 450,000 links. R just crashes when I try to create an adjacency matrix for a large network.

I hope to get a solution from the other folks. I will definitely keep you all posted. Thanks for the time and effort.
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vapor tower