Fast heuristics for minimizing the makespan in non-permutation flow shops.

•We introduce a new permutation representation for non-permutation schedules.•We extend the acceleration technique of Taillard (1990) to the new representation.•We propose new, fast construction, improvement, and iterated greedy heuristics.•The proposed heuristics dominate previous permutation and non-permutation heuristics.•Most non-permutation schedules are shorter than the optimal permutation schedule.