A Simple but Theoretically-Motivated Method to Control Bloat in Genetic Programming

This paper presents a simple method to control bloat which is based on the idea of strategically and dynamically creating fitness “holes” in the fitness landscape which repel the population. In particular we create holes by zeroing the fitness of a certain proportion of the offspring that have above average length. Unlike other methods where all individuals are penalised when length constraints are violated, here we randomly penalise only a fixed proportion of all the constraintviolating offspring. The paper describes the theoretical foundation for this method and reports the results of its empirical validation with two relatively hard test problems, which has confirmed the effectiveness of the approach.