IGIMF in the presence of IMF variations. Upper panel: IGIMF for the case where the IMF of clusters has the same shape (a = 0, reference model), and for models where each of the parameters of the IMF (Γ, γ, and M_ch) has a Gaussian distribution. The width of these Gaussian distributions is described by the parameter a which is the number of times the standard deviations of each of these parameters measured by Dib (2014) for young clusters in the Milky Way (σ_Γ = 0.6, σ_γ = 0.25, and σ_Mch = 0.27 M_⊙). The other input quantities such as the slope of the cluster mass function, minimum and maximum stellar masses, and minimum and maximum cluster mass are the same in all models (see text for details). Lower panel: ratio of each model to the reference model.