As all algorithms do, the Louvain algorithm has its limitations. Understanding them is very important, so we'll try to do that in this section. We will also tackle possible alternatives. Finally, we are also going to talk about some algorithms that allow a node to belong to more than one community.
A caveat of the Louvain algorithm
Like any other algorithm, the Louvain algorithm has some known drawbacks. The main one is the resolution limit.
Resolution limit
Consider the following graph, consisting of strongly connected blobs of seven nodes each, weakly connected to each other with a single edge:
Running community detection on this graph, you would expect each of the blobs to form a community. While this works well for the Louvain algorithm on small graphs, it is known to fail on larger graphs. For instance, when run on a graph with a structure similar to the one depicted in the preceding figure but with 100 blobs, the Louvain...