Distribution of errors of the linear (blue) and nonlinear (orange) emulator as a function of distance from the best-fit model in the w₀w_aCDM subspace (dashed lines) and the w₀CDM+m_ν subspace (solid lines). The x axis represents the maximum σ value used for generating the test set. The “Uniform” case corresponds to generating test samples by uniformly sample parameters in the whole prior range.