The get_pymatgen_structure doesn't allow pbc != 3D

[bastonero]

The get_pymatgen_structure has a strict check on the periodic boundary conditions, raising errors when pbc != (True, True, True). This means that any pbc different from 3D would raise error. As far as I saw in pymatgen core modules, they actually allow for different pbc (e.g. the lattice class allows any pbc).

So one should define a Lattice instance instead of passing directly the self.cell, which is simply array like. The Lattice class also provides pbc in input, so it should be straightforward.

I don't know about older version of pymatgen, maybe they didn't have this class before? Or maybe it wasn't realised at the time?

Originally posted by @bastonero in aiidateam/aiida-quantumespresso#996 (comment)