Cross-validation estimate of the number of clusters in a network
  Network science investigates methodologies that summarise relational data to obtain better interpretability. Identifying modular structures is a fundamental task, and assessment of the coarse-grain level is its crucial step. Here, we propose principled, scalable, and widely applicable assessment criteria to determine the number of clusters in modular networks based on the leave-one-out cross-validation estimate of the edge prediction error. 
Tatsuro Kawamoto and Yoshiyuki Kabashima
cs.SI physics.soc-ph