Tutorial on the NSGA-II crowding distance function

This script illustrates the computation of the crowding distance in the NSGA-II algorithm.

NSGA-II is one of the most popular multi-objective evolutionary optimization algorithms,

introduced by Deb. et al. in 2002 (see "A Fast and Elitist Multiobjective Genetic Algorithm: NSGA-II",

IEEE Trans. on Evolutionary Computation, vol. 6, no. 2, pp. 182-197).

The crowding distance is one of the key elements in NSGA-II.

This function illustrates its computation. It is intended as a tutorial for students willing

to learn NSGA-II.