Heuristics for permutation flow shops to minimize total flowtime

In this paper, permutation flow shop scheduling problem with total flowtime minimization is considered. Two composite heuristics, CH1 and CH2, are proposed which use LR (developed by Liu & Reeves) as index development phase and iterative RZ+FPE-R procedure as solution improvement phase. CH2 also adopts FL to construct a solution. CH1 and CH2 are compared with FLR1, FLR2 and IH7_FL (the best existing composite heuristics for the problem considered in this paper) both in effectiveness and in efficiency. Computational results show that CH1 is the best among the five heuristics in effectiveness and CH2 outperforms the other three. Though time complexity of the five is identical, CPU-time needed by CH1 is at the medium and CH2 is the most time-consuming