A genetic algorithm with combined operators for permutation flowshop scheduling problems

In this paper, a genetic algorithm with combined operators is proposed for the permutation flowshop scheduling problems with the minimization of makespan. First, various operators were tested to choose efficient operators. The crossover operators are combined with suitable mutations operators. Three combinations are selected. They are “010” crossover with shift mutation, cycle crossover with adjacent exchange mutation, and “101” crossover with shift mutation. Then, these chosen combinations of operators are used to form the proposed algorithm. The utilizing ratios of these combinations are determined by heuristic rules. Computer simulation shows promising results and good performance of the algorithm.