Layout of Bayesian networks

Abstract

Bayesian networks are weighted directed acyclic graphs (DAGs). Layout of DAGs has been studied for many years, with variants of the horizontal layering algorithm of Sugiyama et al. (Sugiyama, Tagawa & Toda 1981) the preferred approach for medium size graphs. Following Gansner et al. (Gansner, Koutsofios, North & Vo 1993) we extend the classic horizontal layering algorithm with an additional vertex coordinate assignment phase which is designed to remove overlap between vertices with non-zero width and height. This is required because vertices in the Bayesian network are typically large and may vary greatly in height and width so a major component of good layout is to place vertices closely together without overlap. Our main contribution is to describe and evaluate a variety of novel techniques for vertex coordinate assignment. Copyright © 2005, Australian Computer Society, Inc.