Studying the Properties of Structured Grammatical Evolution

In this report we analyse the properties of Structured Grammatical Evolu-tion (SGE), a new genotypic representation for Grammatical Evolution. In SGE, each gene is linked to a non-terminal of the grammar being used. By using this representation one ensures that the modification of a gene does not affect the derivation options of other non-terminals, thereby increasing local-ity. We use a set of static measures to characterise the interactions between the representation and variation operators and assess how they influence the interplay between the genotype-phenotype spaces. The performance of this new representation is compared with the standard GE on a set of bench-mark problems. The results obtained, statistically validated, show that the adoption of SGE is beneficial.