Top left: learning curve for the train and the test set of the AVG500 dataset, with smoothing θ_s = 2′, for the w₀ parameter. Top right: learning curve for the test set of the AVG100, AVG300, and AVG500 datasets, with smoothing θ_s = 2′, for the w₀ parameter. Bottom left: learning curve for the test set of the AVG300 dataset, with smoothing θ_s = {2′,4′,6′}, for the w₀ parameter. Bottom right: same as in the middle panel but for the Ω_M parameter. In all cases, we performed a three-fold cross-validation.