def test_energy_forces_stress(): """ To test that the calculator can produce correct energy and forces. This is done by comparing the energy for an FCC argon lattice with an example model to the known value; the forces/stress returned by the model are compared to numerical estimates via finite difference. """ import numpy as np from pytest import importorskip importorskip('kimpy') from ase.calculators.kim import KIM from ase.lattice.cubic import FaceCenteredCubic # Create an FCC atoms crystal atoms = FaceCenteredCubic( directions=[[1, 0, 0], [0, 1, 0], [0, 0, 1]], size=(1, 1, 1), symbol="Ar", pbc=(1, 0, 0), latticeconstant=3.0, ) # Perturb the x coordinate of the first atom by less than the cutoff distance atoms.positions[0, 0] += 0.01 calc = KIM("ex_model_Ar_P_Morse_07C") atoms.set_calculator(calc) # Get energy and analytical forces/stress from KIM model energy = atoms.get_potential_energy() forces = atoms.get_forces() stress = atoms.get_stress() # Previously computed energy for this configuration for this model energy_ref = 19.7196709065 # eV # Compute forces and virial stress numerically forces_numer = calc.calculate_numerical_forces(atoms, d=0.0001) stress_numer = calc.calculate_numerical_stress(atoms, d=0.0001, voigt=True) tol = 1e-6 assert np.isclose(energy, energy_ref, tol) assert np.allclose(forces, forces_numer, tol) assert np.allclose(stress, stress_numer, tol) # This has been known to segfault atoms.set_pbc(True) atoms.get_potential_energy()
def test_multi_neighlist(): """ To test that the correct energy/forces/stress can be computed using a model that implements multiple cutoffs. This is done by construct a 10 Angstrom x 10 Angstrom x 10 Angstrom non-periodic cell filled with 15 randomly positioned atoms and requesting tha tthe model compute the energy, forces, and virial stress. The energy returned by the model is compared to a known precomputed value, while the forces and stress returned are compared to numerical estimates via finite difference. """ import numpy as np from ase import Atoms from pytest import importorskip importorskip('kimpy') from ase.calculators.kim import KIM # Create random cluster of atoms positions = np.random.RandomState(34).rand(15, 3) * 10 atoms = Atoms( "Ar" * 15, positions=positions, pbc=False, cell=[[10, 0, 0], [0, 10, 0], [0, 0, 10]] ) calc = KIM("ex_model_Ar_P_Morse_MultiCutoff") atoms.set_calculator(calc) # Get energy and analytical forces/stress from KIM Model energy = atoms.get_potential_energy() forces = atoms.get_forces() stress = atoms.get_stress() # Previously computed energy for this configuration for this model energy_ref = 34.69963483186903 # eV # Compute forces and virial stress numerically forces_numer = calc.calculate_numerical_forces(atoms, d=0.0001) stress_numer = calc.calculate_numerical_stress(atoms, d=0.0001, voigt=True) tol = 1e-6 assert np.isclose(energy, energy_ref, tol) assert np.allclose(forces, forces_numer, tol) assert np.allclose(stress, stress_numer, tol)
pbc=(1, 0, 0), latticeconstant=3.0, ) # Perturb the x coordinate of the first atom by less than the cutoff distance atoms.positions[0, 0] += 0.01 calc = KIM("ex_model_Ar_P_Morse_07C") atoms.set_calculator(calc) # Get energy and analytical forces/stress from KIM model energy = atoms.get_potential_energy() forces = atoms.get_forces() stress = atoms.get_stress() # Previously computed energy for this configuration for this model energy_ref = 19.7196709065 # eV # Compute forces and virial stress numerically forces_numer = calc.calculate_numerical_forces(atoms, d=0.0001) stress_numer = calc.calculate_numerical_stress(atoms, d=0.0001, voigt=True) tol = 1e-6 assert np.isclose(energy, energy_ref, tol) assert np.allclose(forces, forces_numer, tol) assert np.allclose(stress, stress_numer, tol) # This has been known to segfault atoms.set_pbc(True) atoms.get_potential_energy()