This summary of algorithmic knowledge has been made possible with great help from SOFI/ISAAC people: J.G. Cuby, P.A. Duc, C. Lidman, A. Moorwood. Great help has been brought from the EIS (ESO Imaging Survey) people, to test out the code and detail all algorithms. Algorithms were discussed with too many other people to quote them all here, thanks to all of them for their help and support.