Precision of the spectrum prediction by HOTPAYNE, which entails a neural-net-enabled interpolation among Kurucz model spectra. The left panels show the comparison between the Kurucz spectrum and its prediction by HOTPAYNE for a test star with T_eff = 18 236 K, log g = 4.23, and [Fe/H] = 0.0. Top-right panel: distribution of flux residuals for all of our 1012 test spectra, each with 3801 pixels in the wavelength range of λλ3750–9000 Å. A Gaussian fit to the distribution yields a standard deviation of 0.165%. Bottom-right panel: analogous to the top-right panel, but only for pixels whose normalized spectral fluxes are smaller than 0.95, i.e., for strong absorption lines, mostly the cores of H and He lines. The standard deviation from a Gaussian fit is 0.586% for the strong absorption features.