The pixel-domain errors of iterative solutions as T _input − T _output, for the traditional mode (left) and the immediate mode (right) with three rounds of iterations. The input maps are CMB intensity-only simulations based on the Planck 2018 best-fit CMB spectrum (Planck Collaboration et al. 2020), with N _side = 128 and a band limit of ﹩{{\ell }}_{\max }\leqslant 383﹩.