[Python, networkx] community detecting using the modularity

파이썬에는 community라는 package가 있는데, 이 패키지가 아닌 python-louvain이 만든 community라는 패키지를 쓸 것이다.

# 설치 in terminal

pip install python-louvain

# 실행 in notebook

from community import community_louvain
import networkx as nx
import matplotlib.pyplot as plt

#better with karate_graph() as defined in networkx example.
#erdos renyi don't have true community structure
G = nx.erdos_renyi_graph(30, 0.05)

#first compute the best partition
partition = community_louvain.best_partition(G)

#drawing
size = float(len(set(partition.values())))
pos = nx.spring_layout(G)
count = 0.
for com in set(partition.values()) :
    count = count + 1.
    list_nodes = [nodes for nodes in partition.keys()
                                if partition[nodes] == com]
    nx.draw_networkx_nodes(G, pos, list_nodes, node_size = 20,
                                node_color = str(count / size))


nx.draw_networkx_edges(G, pos, alpha=0.5)
plt.show()

참고 : 

https://python-louvain.readthedocs.io/en/latest/

https://github.com/taynaud/python-louvain