Methods for Competitive Co-evolution: Finding Opponents Worth Beating

Chris Rosin
University of California at San Diego

2:30pm Friday July 14 in Room 2310

Co-evolution refers to the simultaneous evolution of two or more genetically distinct populations with coupled fitness landscapes. In this talk I consider ``competitive co-evolution,'' in which the fitness of an individual in a ``host'' population is based on direct competition with individual(s) from a ``parasite'' population. Measured fitness is used to direct the evolution of these populations with a genetic algorithm. I will present results of the application of competitive co-evolution to three game-learning problems: Tic-Tac-Toe (TTT), Nim and a small version of Go. Two new techniques in competitive co-evolution will be described. ``Competitive fitness sharing'' changes the way fitness is measured, and ``shared sampling'' alters the way parasites are chosen for testing hosts. Experiments using TTT and Nim show a substantial improvement in performance when these methods are used. Preliminary results using co-evolution for the discovery of cellular automata rules for playing Go will be presented. (Work done in collaboration with Rik Belew, CSE-UCSD, now visiting Computer Science, Univ. Wisc.)