Some supplementation for NEH heuristic in solving flow shop problem

NEH is the concluded most efficient constructive method in solving the permutation flow shop problem with makespan objective. The original NEH required that all the ties in both the initial permutation and the partial sequences must be enumerated, which will be non-polynomial in the worst case. Several kinds of methods are presented to break the ties in a quick time. Together with the basic method, all the fifteen methods are evaluated on the famous Reeves´ benchmarks and Taillard´s instances, and the most suitable ties breaking policy is recommended.