Profile curves from the NS envelope simulations for the Fe (left panel) and H envelope (right panel). Orange lines indicate the holdout curves used as an alternative test set. In the inset we show a zoom-in illustrating the random assignment of data points to the training (black), validation (green), and test (purple) sets from 90% of the profiles as well as the holdout points (orange) comprised of whole curves (the remaining 10%; see Sect. 2.4 for details).