A multi-level memetic/exact hybrid algorithm for the still life problem

Abstract

Bucket elimination (BE) is an exact technique based on variable elimination. It has been recently used with encouraging results as a mechanism for recombining solutions in a memetic algorithm (MA) for the still life problem, a hard constraint optimization problem based on Conway's game of life. This paper studies expanded multi-level models in which this exact/metaheuristic hybrid is further hybridized with branch-and-bound techniques. A novel variable clustering based recombination operator is also explored, with the aim of reducing the inherent time complexity of BE. Multi-parent recombination issues are analyzed as well. The obtained results are of higher quality than any previous metaheuristic approach, with large instances being solved to optimality. © Springer-Verlag Berlin Heidelberg 2006.