Coverage for gpaw/test/generic/test_move_across_cell.py: 95%

1import pytest 

2from ase.build import molecule 

3 

4from gpaw import GPAW, Davidson, MixerSum 

5 

6# Move atom infinitesimally across cell border and test that SCF loop is still 

7# well converged afterwards. If it is /not/ well converged, then the code 

8# which compensates for discontinuity of phases is probably broken. 

9 

10 

11@pytest.mark.parametrize( 

12 'params', 

13 [dict(mode='pw', 

14 eigensolver=Davidson(3)), 

15 dict(mode='pw', 

16 eigensolver=Davidson(3), 

17 parallel={'gpu': True}), 

18 # pw + lcao extrapolation is currently broken (PWLFC lacks integrate2): 

19 # dict(mode='pw', experimental={'reuse_wfs_method': 'lcao'}), 

20 dict(mode='fd', h=0.3, 

21 eigensolver=Davidson(3), 

22 experimental={'reuse_wfs_method': 'lcao'}), 

23 dict(mode='lcao', basis='sz(dzp)', h=0.3)]) 

24def test_generic_move_across_cell(gpaw_new, params): 

25 params.update( 

26 xc='oldLDA', 

27 # make sure MixerSum works for spin-paired system also: 

28 mixer=MixerSum(0.7), 

29 kpts=[1, 1, 2]) 

30 if not gpaw_new and 'parallel' in params: 

31 params.pop('parallel') 

32 calc = GPAW(**params) 

33 atoms = molecule('H2O', vacuum=2.5) 

34 atoms.pbc = 1 

35 

36 # Translate O to corner: 

37 atoms.positions -= atoms.positions[0, None, :] 

38 

39 # Be sure that we are on the positive axis: 

40 

41 atoms.calc = calc 

42 

43 eps = 1e-12 

44 atoms.positions[0, :] = eps 

45 atoms.get_potential_energy() 

46 atoms.positions[0, 2] -= 2 * eps 

47 atoms.get_potential_energy() 

48 

49 # We should be within the convergence criterion. 

50 # It runs a minimum of three iterations: 

51 if gpaw_new: 

52 assert calc.dft.scf_loop.niter == 2 

53 else: 

54 assert calc.scf.niter == 3