The mean function and kernel act as a prior on the GP. µ ! (𝑥) is usually set to zero because the kernel 𝑘 ! (𝑥, 𝑥 " ) fully expresses any arbitrary function. In this work, we use the Matérn 5/2 kernel, with hyperparameters 𝜽 = {𝜎, 𝑳 } . 𝜎 ∈ ℝ is the scaling hyperparameter and 𝑳 ∈ ℝ ' is a lengthscale that indicates the significance of each input feature.