Application to the linear polarization signals in the Ca ii H and K lines observed in the atlas of (Gandorfer 2002) resampled at 50 wavelength points and with different amounts of noise added for each row. The dots display the observations, with their associated Gaussian error bars (with their standard deviation indicated in the panels). Each column shows the results of the line detection using Gaussian functions of different widths as basis functions. The solid red curve is the mean of the predictive distribution, together with the range inside one standard deviation shown as red dotted lines. The blue curves display the contribution of each individual kernel function. Each panel also displays the evidence ratio and the number of active basis functions.