A survey of modularity in genetic programming

Here, in this paper, we survey work on modularity in Genetic Programming gp. The motivation for modularity was driven by research efforts, as we shall see, to make gp programs smaller and more efficient. In the literature, modularity has commonly used Koza's term, Automatically Defined Functions adf. But, we shall see, that the modularity concept has undergone many name and design changes. From the early ideas of Koza and Price's Defined Building Blocks dbb to Binard and Felty's work with System F and gp Briggs and O'Neill's work with Combinators in gp. Our goal in this paper is to survey the literature on this evolution. This will include Automatically Defined Functions adfs, Automatically Defined Macros adm, Adaptive Representation Through Learning arl, Module Acquisition ma, Hierarchically Defined Local Modules hgp, Higher Order Functions using λ calculus lc and Combinators. We also include critiques by researchers on the viability these various efforts.