title: Modularity clustering is force-directed layout.
abstract: Two natural and widely used representations for the community structure of networks are clusterings, which partition the vertex set into disjoint subsets, and layouts, which assign the vertices to positions in a metric space. This paper unifies prominent characterizations of layout quality and clustering quality, by showing that energy models of pairwise attraction and repulsion subsume Newman and Girvan's modularity measure. Layouts with optimal energy are relaxations of, and are thus consistent with, clusterings with optimal modularity, which is of practical relevance because the two representations are complementary and often used together.
authors.affiliation: Institute of Computer Science, Brandenburg University of Technology, 03013 Cottbus, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Noack