Connecting linear and simulation spectra for the hydrodynamical radiative (CSF) simulation at z = 0. The line colours are as follows: blue is the linear spectrum; dotted red is the simulation spectrum; black is the connecting spectrum. The junction area (marked with the dottet rectangle) is magnified in the inset box, to also show the (mild) effect of the three-point smoothing on the simulation spectrum. Starting from large k, we pass from the simulation spectrum to the linear spectrum, where the former one approaches the latter for the first time.