Solves the Multi-Criteria Minimum Spanning Tree (mc-MST) problem
on complete weighted graphs by combining the Non-dominated Sorting Genetic
Algorithm II (NSGA-II) with optional Pareto local search operators.
Chromosomes are represented as Prufer sequences so that every random
individual decodes to a valid spanning tree (Cayley's theorem), avoiding
repair operators. Four solver variants are provided: pure NSGA-II ("base"),
Path Relinking ("PR"), Pareto Local Search ("PLS"), and Tabu Search ("TS").
The package supports 2 and 3 objective formulations and provides
convenience functions to plot Pareto fronts and best-compromise spanning
trees. This package is the reference implementation of the method
described in Parraga-Alava, Inostroza-Ponta and Dorn (2017)