diff --git a/docs/overview/overview_3_features.md b/docs/overview/overview_3_features.md index a5edf31b..51774bb6 100644 --- a/docs/overview/overview_3_features.md +++ b/docs/overview/overview_3_features.md @@ -153,7 +153,17 @@ captured using a rectangular mesh: Checkout `autogalaxy_workspace/notebooks/features/pixelizations.ipynb` to learn how to use a pixelization, however this is a more advanced feature and it is recommended you first get to grips with the core API. -## Other +## Graphical Models -- Automated pipelines / database tools. -- Graphical models. +The examples above fit each galaxy dataset one-by-one. However, many galaxy properties are shared across a +sample (e.g. the population's distribution of Sersic indices or sizes), and fitting galaxies independently does +not exploit this shared structure. + +Graphical models fit multiple datasets simultaneously, explicitly defining which parameters are unique to each +galaxy and which are shared across the sample. Hierarchical extensions assume parameters are drawn from a parent +distribution, whose properties are inferred from the full sample, extracting significantly more information +than one-by-one fitting. This is a powerful tool for galaxy evolution studies of large samples, for example +measuring how the galaxy population's structural properties vary with mass or redshift. + +Checkout `autofit_workspace/*/features/graphical_models.py` to learn how to compose and fit a graphical model; +the API applies directly to the galaxy fits shown throughout this workspace.