Summary of ICLs and optimal number of clusters as a function of S/N. Top: optimal number of clusters across the different noise levels. All others: ICL as a function of K for different noise levels. In each of the panels, the red boxplot highlights the maximum median value of the ICL i.e. the associated best-fit K value. For the S/N of 500, two behaviours were observed depending on the randomly generated noise. They are both illustrated by the two sets of boxplots (black and grey) in the corresponding panel.