
From:  Danielle Li 
Subject:  [igraph] automating computations on multiple graphs 
Date:  Thu, 5 May 2011 14:23:52 0400 
Hi,
I'm
trying to do some basic social network analysis with igraph in R, but
I'm new to R and haven't been able to find documentation on a couple
basic things:
I want to run igraph's community detection
algorithms on a couple thousand small graphs but don't know how to automate igraph looking at multiple graphs described in a single csv file. My data look like something in ncol format, but with an additional column that has an ID for which graph the edge belongs in:
Graph ID  Vertex1  Vertex2  weight
1  Alice  Bob  2
1  Alice  Chris  1
1  Alice  Jane  2
1  Bob  Jane  2
1  Chris  Jane  3
2  Alice  Tom  2
2  Alice  Kate  1
2  Kate  Tom  3
2  Tom  Mike  2
I want to run community detection on each graph separatelyto look only at the edges when the graph identifier is 1, make calculations on that graph, then do it again for 2 and so forth. I suspect that this isn't related to igraph specificallyI just don't know the equivalent command in R for what in pseudo Stata code would read as:
forvalues i of 1/N {
temp_graph=subrows of the main csv file for which graphid==`i'
cs`i' = leading.eigenvector.community.step(temp_graph)
}
I want the output to look something like:
Graph ID  Vertex1  Vertex2  weight  Vertex 1 membership  Vertex 2 membership  # of communities in the graph
1  Alice  Bob  2  A  B  2
1  Alice  Chris  1  A  B  2
1  Alice  Jane  2  A  B  2
1  Bob  Jane  2  B  B  2
1  Chris  Jane  3  B  B  2
2  Alice  Tom  2  A  B  3
2  Alice  Kate  1  A  C  3
2  Kate  Tom  3  C  B  3
2  Tom  Mike  2  B  C  3
Here, the graphs are treated completely separately so that community A in graph 1 need not have anything to do with community A in graph 2.
I would really appreciate any ideas you guys have.
Thank you!
Danielle
[Prev in Thread]  Current Thread  [Next in Thread] 