这段代码描述多目标遗传算法NSGAII算法的实现，抓要包含三部分：Non-dominated sort， Crowding distance assignment， the selection process来找到pareto-front-The basic operations being performed and the worst case complexities associated with are as follows:

Multi-objective evolutionary algorithms which uses non-dominated sorting to find pareto front. It is consist of tree parts:

• Non-dominated sort returns a list of the non-dominated fronts F. (O(mN 2 ))

•　Crowding distance assignment is O(mNlogN)

•　The crowed comparison operator (Sort on ≥ n) guides the selection process at the various stages of the algorithm towards a uniformly spread out Pareto-optimal front. (O(2Nlog(2N)))