Babel Pidgin: SBSE can grow and graft entirely new functionality into a real world system

Abstract

Adding new functionality to an existing, large, and perhaps poorly-understood system is a challenge, even for the most competent human programmer. We introduce a 'grow and graft' approach to Genetic Improvement (GI) that transplants new functionality into an existing system. We report on the trade offs between varying degrees of human guidance to the GI transplantation process. Using our approach, we successfully grew and transplanted a new 'Babel Fish' linguistic translation feature into the Pidgin instant messaging system, creating a genetically improved system we call 'Babel Pidgin'. This is the first time that SBSE has been used to evolve and transplant entirely novel functionality into an existing system. Our results indicate that our grow and graft approach requires surprisingly little human guidance. © 2014 Springer International Publishing Switzerland.