Peter Munch

As far as I remember, we do not support MatrixFree+hp+DG(aka. MatrixFree::loop). But let me check tomorrow what is missing for your use case (I have recently misused and extended the...

> It's right, we don't support it right now, but I think the combination FE_Q/FE_DGQ plus FE_Nothing should be relatively simple to address, because we merely need to consider the...

I am kicked out here (during setup of the mapping data in the quadrature points): https://github.com/dealii/dealii/blob/42e48fa22db833282dd8a38858c44dda94fd03dc/include/deal.II/matrix_free/mapping_info.templates.h#L2084-L2087 which makes sense since `n_q_points` is selected for the interior face (which happens to...

A face is created here: https://github.com/dealii/dealii/blob/42e48fa22db833282dd8a38858c44dda94fd03dc/include/deal.II/matrix_free/face_setup_internal.h#L947-L1021 and they are inserted into the global data structures here: https://github.com/dealii/dealii/blob/42e48fa22db833282dd8a38858c44dda94fd03dc/include/deal.II/matrix_free/face_setup_internal.h#L770-L935 I am happy to help out. However, we should agree if the proposed...

> Another way would be to allow MatrixFree to take a predicate similar to what I did for CUDA #11780 This allows me to only loop over cells of a...

`MappingFE` works currently only for a single manifold, since the following lines of code are not as general as in the `MappingQ` case: https://github.com/dealii/dealii/blob/208d70583f97a62e976bc007e6e099aa6c79dd1b/source/fe/mapping_fe.cc#L2277-L2300 vs. https://github.com/dealii/dealii/blob/208d70583f97a62e976bc007e6e099aa6c79dd1b/source/fe/mapping_q.cc#L1678-L1773 At the moment, the...

> Would you say that the needed adaptions are limited to compute_mapping_support_points? Yes and the setup of the interpolation matrices: https://github.com/dealii/dealii/blob/208d70583f97a62e976bc007e6e099aa6c79dd1b/source/fe/mapping_fe.cc#L864-L871 Let me quickly explain what `compute_mapping_support_points()` (currently) does. It...

@luca-heltai

@bangerth What is the progress here?

@bangerth What is missing there? The above stated TODOs are fixed in the mean time.