Hello,

I have been using the geometrical periodic BC for dolfinx_mpc, but now my project goes to 3D problem, and I find that the geometrical PBC doesn’t work anymore.

In order to find the bug, I test the basic linear transport problem:

in unit domains(interval, square and cube), and it turns out that it works well for 1D and 2D(even when the PBC is on both directions) case, but for 3D case, the result doesn’t seem to be **“periodic”** even if I only impose PBC on one direction.

So I want to ask, is there any limit to the geometrical periodic BC, should I use topological periodic BC instead?

Thanks in advance.