Document external calculators?

[ElliottKasoar]

I'm not proposing we actively work towards more support from other calculators, but it may be useful to note that most janus calculations (should) already work with any ASE-compatible calculator. For example:

from janus_core.calculations.single_point import SinglePoint
from ase.calculators.lj import LennardJones
from ase.io import read

struct = read("tests/data/NaCl.cif")
struct.calc = LennardJones()

single_point = SinglePoint(
    struct=struct,
)

print(single_point.run())

returns

{'energy': -0.05900093815771919, 'forces': array([[0., 0., 0.],
       [0., 0., 0.],
       [0., 0., 0.],
       [0., 0., 0.],
       [0., 0., 0.],
       [0., 0., 0.],
       [0., 0., 0.],
       [0., 0., 0.]]), 'stress': array([0.00211953, 0.00211953, 0.00211953, 0.        , 0.        ,
       0.        ])}

This might help make a comparison with DFT/classical force fields, or enable the use of a currently unsupported MLIP, so perhaps work documenting?

[alinelena]

good point, add a section in documentation about it