def test_CH(self):
vac = 4
dist_min = 0.8
dist_max = 1.9
a = Atoms('CH', positions=[[0, 0, 0], [dist_min, 0, 0]])
a.center(vacuum=vac)
distances = np.linspace(dist_min, dist_max, 1000)
for potential in [Rebo2(), Rebo2Scr()]:
a.set_calculator(potential)
energies = []
forces = []
for dist in distances:
a[1].position[0] = dist + vac
forces += [a.get_forces()[0][0]]
energies += [a.get_potential_energy()]
forces = np.array(forces)
energies = np.array(energies)
en_differences = np.abs(energies[1:] - energies[:-1])
self.assertTrue(np.max(en_differences) < 0.03)
self.assertTrue(np.max(np.abs(forces[1:] - forces[:-1])) < 0.3)
def test_energy(self):
vac = 8
dist_min = 1.2
atoms = Atoms('CC', positions=[[0, 0, 0], [dist_min, 0, 0]])
atoms.center(vacuum=vac)
for calc in [Rebo2(), Rebo2Scr()]:
atoms.calc = calc
energy = atoms.get_potential_energy()
forces_ac = atoms.get_forces()
stress = atoms.get_stress()
fname = 'structure.traj'
atoms.write(fname)
atoms = io.read(fname)
self.assertTrue(
np.abs(energy - atoms.get_potential_energy()) < 1e-10)
self.assertTrue(
(np.abs(forces_ac - atoms.get_forces()) < 1e-10).all())
self.assertTrue(
(np.abs(stress - atoms.get_stress()) < 1e-10).all())