I have a part of my code in which it is simpler (far less
ifs and edge cases) if I add empty constraints first and then, knowing all constraints I need are present in the model, change the coefficient of some variables inside newly added and old constraints.
I have searched the Discourse but the topics I found are from 2017 (before the great change in JuMP I think), and none really addresses the question.
There is a way to do this? I will need to rework more code if I cannot do it.