Choosing selection pressure for wide-gap problems

To exploit an evolutionary algorithm's performance to the full extent, the selection scheme should be chosen carefully. Empirically, it is commonly acknowledged that low selection pressure can prevent an evolutionary algorithm from premature convergence, and is thereby more suitable for wide-gap problems. However, there are few theoretical time complexity studies that actually give the conditions under which a high or a low selection pressure is better. In this paper, we provide a rigorous time complexity analysis showing that low selection pressure is better for the wide-gap problems with two optima. (C) 2009 Elsevier B.V. All rights reserved.