Analyzing directed acyclic graph recombination

This work studies the edge-based representation of directed acyclic graphs, as well as the properties of recombination operators working on it. It is shown that this representation is not separable, and the structure of the basic information units that must be processed in order to maintain feasibility of the solutions is described. As an experimental analysis indicates, a recombination operator using these units has subquadratic complexity in the graph size. It is also shown that a standard gene-transmission recombination operator is biased to produce solutions of lower edge-density than the parents' average. An unbiased allelic recombination operator provides better results on an ad-hoc test problem.