Coverage for gpaw/test/xc/test_revPBE.py: 100%

1from ase import Atoms 

2from gpaw import GPAW, PoissonSolver 

3import pytest 

4from ase.units import Bohr, Hartree 

5 

6 

7def test_xc_revPBE(): 

8 a = 7.5 * Bohr 

9 n = 16 

10 atoms = Atoms('He', [(0.0, 0.0, 0.0)], cell=(a, a, a), pbc=True) 

11 params = dict(mode='fd', 

12 gpts=(n, n, n), 

13 nbands=1, 

14 xc={'name': 'PBE', 'stencil': 1}, 

15 poissonsolver=PoissonSolver('fd')) 

16 atoms.calc = GPAW(**params) 

17 e1 = atoms.get_potential_energy() 

18 e1a = atoms.calc.get_reference_energy() 

19 params['xc'] = {'name': 'revPBE', 'stencil': 1} 

20 atoms.calc = GPAW(**params) 

21 e2 = atoms.get_potential_energy() 

22 e2a = atoms.calc.get_reference_energy() 

23 

24 assert e1a == pytest.approx(-2.893 * Hartree, abs=8e-3) 

25 assert e2a == pytest.approx(-2.908 * Hartree, abs=9e-3) 

26 assert e1 == pytest.approx(e2, abs=4e-3) 

27 

28 energy_tolerance = 0.0005 

29 assert e1 == pytest.approx(-0.0790449962, abs=energy_tolerance) 

30 assert e2 == pytest.approx(-0.08147563, abs=energy_tolerance)