Facet normal/side difference between dolfin/multiphenics and dolfinx//multiphenicsx


I was confused regarding how (‘+’) and (‘-’) are defined for internal boundaries in dolfinx/multiphenicsx. In the dolfin-lagacy and multiphenics, by adding a volume measure, (‘+’)/(‘-’) represent the side with a bigger/smaller meshtag (here). Is it still the same for the newer versions? In other words, if we have a weak form containing these signs, can we use the same weak form in dolfinx/multiphenicsx without any further consideration?

It is not. I have an example of how to get consistent orientations at

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As always, thank you so much Jorgen! It works perfectly.
Just a quick correction: in the link you shared, a [0] is missing in the part


; it should be changed to


(at least for my version of dolfinx which is 0.7.3).

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