latent-variable model

On the weekend Adrian Price-Whelan and I decided that we have to implement the linear latent-variable model (our name!), which is a generative model for both features and labels, if we are going to do well labeling stars with ESA Gaia XP spectra at low signal-to-noise (faint magnitudes). The reason is: The latent-variable model generates the data, so it deals naturally with the different noise in stars of different brightnesses (or different signal-to-noise). We think this is important! We'll see this coming week.