Matrix analysis of genetic programming mutation

Abstract. Heuristic policies for combinatorial optimisation problems can be found by using Genetic programming (GP) to evolve a mathe-matical function over variables given by the current state of the problem, and whose value is used to determine action choices (such as preferred assignments or branches). If all variables have finite discrete domains, then the expressions can be converted to an equivalent lookup table or ‘decision matrix’. Spaces of such matrices often have natural distance metrics (after conversion to a standard form). As a case study, and to support the understanding of GP as a meta-heuristic, we extend previous bin-packing work and compare the distances between matrices from be-fore and after a GP-driven mutation. We find that GP mutations often correspond to large moves within the space of decision matrices. This gives evidence that the role of mutations within GP might be somewhat different than their role within Genetic Algorithms.