Slip boundary conditions

Hm I guess then your best option is to create a map of element number to dofs and in each timestep clear the freedofs and then use the map to set the marked dofs. This is most likely faster than iterating over all elements.
Best
Christopher

Thank you for your advice! I think I can do it even more simply: Before the time loop, I create list of the dofs which need to be set on the slip boundary, and in each time step I loop just over this list and set the respective dofs.

Best wishes, Henry

As I have not seen this in the online documentation yet, for reference to anyone who might also need this: I have seen that the VectorH1 space now takes the arguments dirichletx, dirichlety and dirichletz to set separate Dirichlet BCs on the components of the space.