Minor addition of some variables in SetupFromSpglib()

[ManexAlkorta]

Addition to support the new function get_free_energy_hessian_dev() in python-sscha

[mesonepigreco]

Hi Manex,
Can you briefly explain what the new variables are used for and what their expected sizes are? This in cellconstructor should be a really trivial addition; however, we must be careful, as they are allocated a lot inside the sscha code, and I see they are a 3-rank tensor (I assume symmetries X nat X 3, am I right? Is the structure in the primitive or in the supercell? In this case, it should be safe for memory, as it is likely the same memory as one configuration of the ensemble per symmetry, and usually we have a much larger number of configurations than symmetries)

[mesonepigreco]

@ManexAlkorta It seems there is a failure in one of the test, can you check?

[ManexAlkorta]

Hi Lorenzo,

This pull request includes two new new attributes to the QE_symmetry class:

• self.QE_s_cart. Dimension [3,3,48]. Point group symmetries of the crystal in cartesian coordinates, let's call it S.
• self.QE_s_inv_cart. Dimension [3,3,48]. Inverse of the point group symmetries of the crystal, S.T or S^{-1}.

In the end these are just the point symmtry operation in cartesian coordinates of the crystal, S and S.T. This allows reading it directly from the SetupFromSpglib function instead of making the conversion from crystal units in python-sscha.

Regarding the conflict in the test, I think it has nothing to do with this commit, but with the master branch that i cloned to add these changes. I checked the master branch (commit 311af57) and i see the same issue:

FAILED tests/ImportFromPhonons/test_asephonons.py::test_ase_phonons - AttributeError: 'Phonons' object has no attribute 'N_c'

[mesonepigreco]

Hi @ManexAlkorta , you were right, it is a new ASE deprecation that made the test not pass when installed with newer versions (a time bomb -.-). I have fixed the error in the master. Can you update the branch to the latest master commit so we can rerun the test suite in CI to verify that no other errors occur?

[ManexAlkorta]

I updated merged the branch into master in my forked repo. I guess now should be fine