Fig. 8

Convergence of the Gaussian process regression model for the likelihood function over number of training points \(n_\textrm{train}\) (forward model evaluations). a \(n_\textrm{train}=10\), b \(n_\textrm{train}=20\), c \(n_\textrm{train}=50\), d \(n_\textrm{train}=100\), e \(n_\textrm{train}=200\), f \(n_\textrm{train}=900\). In all cases the same Sobol sequence was used to generate a space-filling training data set. Training samples as circles for successful and gray crosses (left side) for failed forward model evaluations