Abstract
Grammatical Evolution (GE) is a method for optimizing the program generated by a one-dimensional chromosome and grammatical rules. GE has an advantage that invalid individuals are not generated by the genetic operations. When a certain gene changes, however, the successive genes might be used for the production rule different from the rule applied before even if they are not changed. Therefore, it is difficult to preserve the character of parents. To solve this problem, we propose GE using multiple chromosomes. In this method, multiple chromosomes as many as the non-terminal symbols in the grammatical rules are prepared. A chromosome according to the expanded non-terminal symbol is selected and used for mapping. Moreover, the technique of the wrapping are improved so that the grammatical rules which increase the number of non-terminal symbols cannot be applied when the wrapping happens. We performed some experiments, and showed the effectiveness of our proposed method.
