General workflow of CIGALE for SED fitting and parameter estimation. It can be split into 4 broad consecutive steps: 1) input handling in which configuration and data files are processed, 2) model generation in which the model SEDs and the associated physical properties are computed and stored in memory, 3) analysis in which the models are fitted to the observations and physical properties are estimated through the PDF, and finally 4) output handling in which the results are saved to disk. The input and output steps are shown in green, the parallel computation of the models and of the fits are shown in blue, and the main data residing in shared memory are shown in red.