Hello everyone!
Looking at the basix documentation (Basix documentation) I can see that the connectivity of a quadrilateral element is
2 ------ 3
| … … |
0 ------ 1
however, after creating a mesh using the mesh::create_rectangle, the obtained connectivity looks like
1 ------ 3
| … … |
0 ------ 2
Notice that this is not just a planar rotation of the one above.
Actually, looking at the DOLFINx code in charge of generating the rectangle mesh for quads the obtained connectivity makes perfect sense (see https://github.com/FEniCS/dolfinx/blob/8eefd77b79b8ddadfd7d320c0cae4665b61287e3/cpp/dolfinx/mesh/generation.h#L624C15-L624C15)
I am clueless about this. Are both connectivities right? Can I trust that the meshes always follow the second one?
Thanks,
Pablo