Left panel: arithmetic mean of the H₂O absorption coefficient between 1000  cm^-1 and 1001  cm^-1 calculated using the adaptive (AK), fixed width (FW), fixed factor (FF) cut-off schemes as a function of the cut-off parameters (f_AK, d_FW and f_FF, respectively) at 10⁵  Pa, 1500  K. The mean absorption coefficients have been normalised by the value obtained using AK with f_AK = 10^-8. Right panel: computation time required using 12 cores at 2.8  GHz as a function of the cut-off parameter. We see that our adaptive cut-off scheme is about two orders of magnitude faster than the two other methods for a given average absorption coefficient.