Coverage for gpaw/test/test_fixocc.py: 100%

1from ase.build import molecule 

2from ase.parallel import parprint 

3from gpaw import GPAW 

4from gpaw.utilities.adjust_cell import adjust_cell 

5import pytest 

6 

7 

8def test_fixocc(): 

9 h = 0.4 

10 box = 2 

11 nbands = 2 

12 txt = '-' 

13 txt = None 

14 

15 H2 = molecule('H2') 

16 adjust_cell(H2, box, h) 

17 convergence = {'energy': 0.01, 'eigenstates': 0.001, 'density': 0.01} 

18 

19 base_kwargs = dict( 

20 mode='fd', 

21 h=h, 

22 nbands=nbands, 

23 convergence=convergence, 

24 txt=txt) 

25 

26 if 1: 

27 # test ZeroKelvin vs FixedOccupations 

28 c = GPAW(**base_kwargs, occupations={'width': 0.0}) 

29 H2.calc = c 

30 E_zk = H2.get_potential_energy() 

31 

32 c = GPAW(**base_kwargs, 

33 occupations=dict(name='fixed', numbers=[[1, 0]])) 

34 H2.calc = c 

35 E_fo = H2.get_potential_energy() 

36 parprint(E_zk, E_fo) 

37 assert E_zk == pytest.approx(E_fo, abs=1.e-10) 

38 

39 if 1: 

40 # test spin-paired vs spin-polarized 

41 c = GPAW(**base_kwargs, 

42 occupations={'name': 'fixed', 'numbers': [[0.5, 0.5]]}) 

43 H2.calc = c 

44 E_ns = H2.get_potential_energy() 

45 if 1: 

46 c = GPAW(**base_kwargs, 

47 spinpol=True, 

48 occupations={'name': 'fixed', 'numbers': [[0.5, 0.5]] * 2}) 

49 H2.calc = c 

50 E_sp = H2.get_potential_energy() 

51 parprint(E_ns, E_sp) 

52 assert E_ns == pytest.approx(E_sp, abs=1.e-6)