Compressing network populations with modal networks reveals structural diversity

TL;DR

This paper introduces nonparametric, scalable methods based on the minimum description length principle to automatically identify representative networks and structural diversity within populations of relational data, including multilayer and temporal networks.

Contribution

It presents novel, efficient algorithms for extracting key network prototypes and heterogeneity, applicable to various types of network data, with a focus on automation and scalability.

Findings

Successfully recover planted heterogeneity in synthetic data

Identify structural heterogeneities in global trade networks

Detect essential patterns in fossil record networks

Abstract

Analyzing relational data consisting of multiple samples or layers involves critical challenges: How many networks are required to capture the variety of structures in the data? And what are the structures of these representative networks? We describe efficient nonparametric methods derived from the minimum description length principle to construct the network representations automatically. The methods input a population of networks or a multilayer network measured on a fixed set of nodes and output a small set of representative networks together with an assignment of each network sample or layer to one of the representative networks. We identify the representative networks and assign network samples to them with an efficient Monte Carlo scheme that minimizes our description length objective. For temporally ordered networks, we use a polynomial time dynamic programming approach that restricts the clusters of network layers to be temporally contiguous. These methods recover planted heterogeneity in synthetic network populations and identify essential structural heterogeneities in global trade and fossil record networks. Our methods are principled, scalable, parameter-free, and accommodate a wide range of data, providing a unified lens for exploratory analyses and preprocessing large sets of network samples.