# cdlib.evaluation.surprise¶

surprise(graph: <Mock id='139911972658512'>, communities: object, **kwargs) → object

Surprise is statistical approach proposes a quality metric assuming that edges between vertices emerge randomly according to a hyper-geometric distribution.

According to the Surprise metric, the higher the score of a partition, the less likely it is resulted from a random realization, the better the quality of the community structure.

Parameters: graph – a networkx/igraph object communities – NodeClustering object FitnessResult object

Example:

>>> from cdlib.algorithms import louvain
>>> from cdlib import evaluation
>>> g = nx.karate_club_graph()
>>> communities = louvain(g)
>>> mod = evaluation.surprise(g,communities)

1. Traag, V. A., Aldecoa, R., & Delvenne, J. C. (2015). Detecting communities using asymptotical surprise. Physical Review E, 92(2), 022816.