Figure reports per-molecule, temperature-reduced entropy difference (in units of k B ) between the two forms of ice (Ic and XI), estimated using the different methods. In these comparisons, the two temperatures are plotted separately. Figures ) and Figure (i,ii) report estimates obtained from the PGM models H and C respectively, plotted as a function of the training progress. The differences between panels A and B in Fig. indicate that model H was able to converge more rapidly and with lower variance compared to model C. These estimates are systematically comparable to the ECM ground truth (straight black lines).