Comment (by Miguel Zilhão):

In any case, it is easy trivial to implement the behavior I describe: the simplest way is to put a conditional in front of the code that writes rhs_lapse and rhs_shift checking if lapse_evolution_method is LeanBSSNMoL

This should be very simple to implement, yes. Gabriele, do you want to propose a patch, or a PR?

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2487/_evolution_method-leanbssnmol-in-lean-does