Replication Results¶

At first, I tried for an independent and isolated replication. That is, I didn't peak at their source code. Unfortunately, the paper left some ambiguities.

The authors' write:

As before, the network is initialized by starting with no edges and running the first two steps (addition of connections)􏰄 without the third 􏰍(breaking any connections)􏰄 until all or most vertices have degree z*. Then all three steps are used for the remainder of the simulation.

I implemented this as a barrier. That is, once some proportion of nodes had degree z*, the friendship removal function could run. Yet, what is "most"? I tried varying proportions, hoping to yield the appropriate clustering coefficient. I was unsuccessful.

Unfortunately, the JinGir implementation I found was incorrect. It used the wrong proportions for selection. (I don't think the authors of the paper wrote it.) But, it pointed me in the right direction with respect to the barrier. Still, my clustering coefficient remained too high. They reported a clustering coefficient, C, of 0.53. Using the same parameters, I never achieved a level that low.

Finally, I reached out to the authors for the code. (Thank you, Michelle Girvan and M. E. J. Newman!) After perusing it, the (obvious) missing specification jumped out -- they ran the algorithm for 30,000 iterations! I was only running it for a few hundred iterations. After this modification, my clustering coefficient comported to theirs.

I consider this to be a success.