[igraph] community detection

[zhengjun chen]

Hi,

I run fastgreedy community detection algorithm on my dataset. I get a number of communities, and the modularity is 0.586.

Then I take a look at one of the communities. It has 170 vertices. 

I found it has 253 edges inside the community, but 391 edges towards vertices outside the community.

This is contrary to my intuition of community. A good community should have more edges inside, and less edges towards outside.

So, what is wrong?

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Thanks
zhengjun

Graduate research assistant
Dept of Computer Science and Engineering
Lehigh University