For MOO, peptides forming the Pareto front are chosen as the new batch. If the required batch size is smaller than the number of peptides composing the Pareto front, selection is based on crowding distances, giving preference to peptides with larger distances between their nearest neighbors for a more diverse batch. Conversely, when the batch size exceeds the Pareto front, additional peptides from the next ranks, beginning with rank 2 (i.e. the Pareto front is considered to be rank 1), supplement the batch. If a rank has more peptides than needed, crowding distances are assessed, considering only the peptides previously selected from earlier ranks; if not, all peptides in that rank are chosen.