Spectra, cross-correlation coefficient and Dice coefficient for baseline timewarper on 2D data. (a) Average power spectra from predictions from input redshifts z = 3 → 0 (blue scale), and average target spectrum at z = 0 (black). (b) Corresponding average cross-correlation coefficient between prediction and target over the same redshift range. (c) Average Dice coefficient between prediction and target (same blue color scale as in a and b).