  We discuss the current minimisation strategies adopted by research projects
involving the determination of parton distribution functions (PDFs) and
fragmentation functions (FFs) through the training of neural networks. We
present a short overview of a proton PDF determination obtained using the
covariance matrix adaptation evolution strategy (CMA-ES) optimisation
algorithm. We perform comparisons between the CMA-ES and the standard nodal
genetic algorithm (NGA) adopted by the NNPDF collaboration.
