This paper presents a biased random-key genetic algorithm
for k-medoids clustering problem. A novel heuristic
operator was implemented and combined with a parallelized local
search procedure. Experiments were carried out with fifty literature
data sets with small, medium, and large sizes, considering several numbers
of clusters, showed that the proposed algorithm outperformed
eight other algorithms, for example, the classics PAM and CLARA
algorithms. Furthermore, with the results of a linear integer programming
formulation, we found that our algorithm obtained the global
optimal solutions for most cases and, despite its stochastic nature, presented
stability in terms of quality of the solutions obtained and the
number of generations required to produce such solutions. In addition,
considering the solutions (clusterings) produced by the algorithms, a
relative validation index (average silhouette) was applied, where, again,
was observed that our method performed well, producing cluster with a
good structure.