Logigram recalling the procedure of the calculation of the perturbed DF. The different steps 1-5 correspond respectively to the modes DFpos, FCorb, FCgrid, FCforDF, and PertDF. There are two cases where the result of the code needs to be verified: after the third step (to check that the decomposition is correct) and after the fourth step (to check that the perturbing potential is well reproduced).