A Niched-Penalty Approach for Constraint Handling in Genetic Algorithms

Kalyanmoy Deb and Samir Agrawal Kanpur Genetic Algorithms Laboratory (KanGAL), Department of Mechanical Engineering, Indian Institute of Technology Kanpur, PIN 208 016, India E-mail: deb,samira @iitk.ac.in Abstract Most applications of genetic algorithms (GAs) in handling constraints use a straightforward penalty function method. Such techniques involve penalty parameters which must be set right in order for GAs to work. Although many researchers use adaptive variation of penalty parameters and penalty functions, the general conclusion is that these variations are specific to a problem and cannot be generalized. In this paper, we propose a niched-penalty approach which does not require any penalty parameter. The penalty function creates a selective pressure towards the feasible region and a niching maintains diversity among feasible solutions for the genetic recombination operator to find new feasible solutions. The approach is only applicable to population-based approaches, thereby giving GAs (or other evolutionary algorithms) a niche in exploiting this penalty-parameter-less penalty approach. Simulation results on a number of constrained optimization problems suggest the efficacy of the proposed method.