Skip to main content

Cython implementation of the classic Louvain algorithm for community detection in graphs

Project description

cylouvain is a Python module that provides a fast implementation of the classic Louvain algorithm for node clustering in graph.

This module uses Cython in order to obtain C-like performance with code mostly writen in Python.


Install the latest version of cylouvain using pip

$ pip install cylouvain


cylouvain requires:

  • Python (>= 2.7 or >= 3.4)
  • NumPy
  • SciPy
  • NetworkX

Simple example

Build a simple graph with NetworkX:

>>> import networkx as nx
>>> graph = nx.Graph()
>>> graph.add_nodes_from(['a', 'b', 'c', 'd', 'e'])
>>> graph.add_edges_from([('a', 'b'), ('a', 'c'), ('b', 'c'),
                          ('c', 'd'), ('c', 'e'), ('d', 'e')])

Compute a partition of the nodes using cylouvain:

>>> import cylouvain
>>> partition = cylouvain.best_partition(graph)
>>> print(partition)
{'a': 0, 'b': 0, 'c': 0, 'd': 1, 'e': 1}

Compute the corresponding modularity:

>>> modularity = cylouvain.modularity(partition, graph)
>>> print("Modularity: %0.3f\n" % modularity)
Modularity: 0.111


The Louvain algorithm is an heuristic to find a node partition that maximizes the modularity function. It is described in:

Fast unfolding of communities in large networks
Vincent D Blondel, Jean-Loup Guillaume, Renaud Lambiotte, Etienne Lefebvre
Journal of Statistical Mechanics: Theory and Experiment 2008 (10), P10008 (12pp)

The modularity function was first introduced in:

Finding and evaluating community structure in networks
Newman, Mark EJ and Girvan, Michelle
Physical review E, 2004, vol. 69, no 2, p. 026113.


Released under the 3-Clause BSD license (see COPYING):

Copyright (C) 2018 Alexandre Hollocou <>

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
cylouvain-0.2.2.tar.gz (131.9 kB) Copy SHA256 hash SHA256 Source None

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN SignalFx SignalFx Supporter DigiCert DigiCert EV certificate StatusPage StatusPage Status page