new droplet attribute: diffusional_growth_mass_change (a temporary kludge without support for collisional processes); new initialisers mechanism in Particulator

[AgnieszkaZaba]

Changes taken from #1757

[slayoo]

thanks!

[AgnieszkaZaba]

I got this error:

FAILED [ 50%]
tests/unit_tests/attributes/test_diffusional_growth_mass_change.py:9 (test_diffusional_growth_mass_change[CPU])
backend_instance = <PySDM.backends.numba.Numba object at 0x108dbd490>

    def test_diffusional_growth_mass_change(backend_instance):
        """check diffusional growth mass change updated after Condensation"""
        # arrange
        n_sd = 1
        dt = 1 * si.s
    
        builder = Builder(
            backend=backend_instance, n_sd=n_sd, environment=MoistBox(dt=dt, dv=np.nan)
        )
        builder.add_dynamic(AmbientThermodynamics())
        builder.add_dynamic(Condensation())
        builder.request_attribute("diffusional growth mass change")
        particulator = builder.build(
            attributes={
                "water mass": np.ones(n_sd) * si.ng,
                "multiplicity": np.ones(n_sd),
                "dry volume": (dry_volume := np.ones(n_sd) * si.nm**3),
                "kappa times dry volume": np.ones(n_sd) * dry_volume * 0.6,
            }
        )
        particulator.environment["rhod"] = 1 * si.kg / si.m**3
        particulator.environment["thd"] = 300 * si.K
        particulator.environment["water_vapour_mixing_ratio"] = 10 * si.g / si.kg
    
        # act
>       particulator.run(steps=1)

tests/unit_tests/attributes/test_diffusional_growth_mass_change.py:35: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
PySDM/particulator.py:59: in run
    dynamic()
PySDM/dynamics/condensation.py:104: in __call__
    self.particulator.condensation(
PySDM/particulator.py:153: in condensation
    v_cr=self.attributes["critical volume"],
PySDM/impl/particle_attributes.py:93: in __getitem__
    return self.__attributes[item].get()
PySDM/attributes/impl/attribute.py:32: in get
    self.update()
PySDM/attributes/impl/derived_attribute.py:23: in update
    self.recalculate()
PySDM/attributes/physics/critical_volume.py:35: in recalculate
    else self.environment["T"]
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <tests.unit_tests.dynamics.test_vapour_deposition_on_ice.MoistBox object at 0x112b73cb0>
item = 'T'

    def __getitem__(self, item):
>       return self._ambient_air[item]
E       KeyError: 'T'

PySDM/environments/box.py:20: KeyError

@slayoo Do you know what else I should fix/update?