Influence of pRNGs onto GPA-ES behaviors

Abstract

The main aim of this paper is to investigate if the evolutionary algorithms (EAs) can be influenced by (pseudo) Random Number Generators ((p)RNGs) and if different evolutionary operators applied within EAs requires different features of (p)RNGs. This question is significant especially if genetic programming is applied to symbolic regression task with the aim to produce human expert comparable results because such task requires massive computations. Experiments were performed on GPA-ES algorithm combining genetic programming algorithm (GPA) for structure development and evolutionary strategy (ES) algorithm for parameter optimization. This algorithm is described bellow and it applies extended scale of different evolutionary operators (additional individuals generating, symmetric crossover, mutations, and one point crossover). These experiments solved problem of symbolic regression of dynamic system. The number of iterations needed for required quality of regression was used as the measure of (p)RNG influence. These experiments point that different (p)RNGs fit to different evolutionary operators, that some combinations (p)RNGs are better than others and that some theoretically excellent (p)RNGs produces poor results. Presented experiments point that the efficiency of evolutionary algorithms might be increased by application of more (p)RNGs in one algorithm optimised for each particular evolutionary operator.