A nonuniform popularity-similarity optimization (nPSO) model to efficiently generate realistic complex networks with communities

TL;DR

The paper introduces the nonuniform PSO (nPSO) model, a new method for efficiently generating realistic complex networks with controllable community structures in hyperbolic space, improving over previous models like GPA.

Contribution

The nPSO model explicitly controls community number and size, tunes community mixing via network temperature, and efficiently generates highly clustered networks with realistic community organization.

Findings

nPSO accurately reproduces community structures in hyperbolic networks.

It allows explicit control over community number and size.

The model is efficient and suitable for benchmarking community detection and link prediction.

Abstract

The hidden metric space behind complex network topologies is a fervid topic in current network science and the hyperbolic space is one of the most studied, because it seems associated to the structural organization of many real complex systems. The Popularity-Similarity-Optimization (PSO) model simulates how random geometric graphs grow in the hyperbolic space, reproducing strong clustering and scale-free degree distribution, however it misses to reproduce an important feature of real complex networks, which is the community organization. The Geometrical-Preferential-Attachment (GPA) model was recently developed to confer to the PSO also a community structure, which is obtained by forcing different angular regions of the hyperbolic disk to have variable level of attractiveness. However, the number and size of the communities cannot be explicitly controlled in the GPA, which is a clear limitation for real applications. Here, we introduce the nonuniform PSO (nPSO) model that, differently from GPA, forces heterogeneous angular node attractiveness by sampling the angular coordinates from a tailored nonuniform probability distribution, for instance a mixture of Gaussians. The nPSO differs from GPA in other three aspects: it allows to explicitly fix the number and size of communities; it allows to tune their mixing property through the network temperature; it is efficient to generate networks with high clustering. After several tests we propose the nPSO as a valid and efficient model to generate networks with communities in the hyperbolic space, which can be adopted as a realistic benchmark for different tasks such as community detection and link prediction.