Coverage for gpaw/test/lcao/test_scissors.py: 96%

1import pytest 

2from ase import Atoms 

3from gpaw.new.ase_interface import GPAW 

4from gpaw.lcao.scissors import non_self_consistent_scissors_shift as nsc_shift 

5from gpaw.spinorbit import soc_eigenstates 

6from gpaw.mpi import world 

7 

8 

9def test_scissors(): 

10 """Opens gap in one of two isolated H2 moleculs.""" 

11 h2 = Atoms('2H2', [[0, 0, 0], [0, 0, 0.74], 

12 [4, 0, 0], [4, 0, 0.74]]) 

13 h2.center(vacuum=3.0) 

14 d = 1.0 

15 h2.calc = GPAW(mode='lcao', 

16 basis='sz(dzp)', 

17 eigensolver={'name': 'scissors', 

18 'shifts': [(-d, d, 2)]}, 

19 symmetry='off', 

20 parallel={'domain': 1, 

21 'band': world.size, 

22 'sl_auto': True}, 

23 txt=None) 

24 h2.get_potential_energy() 

25 eigs1 = h2.calc.get_eigenvalues() 

26 

27 i, ii, iii, iv = eigs1 

28 assert ii - i == pytest.approx(d, abs=0.01) 

29 assert iv - iii == pytest.approx(d, abs=0.01) 

30 

31 # Non self-consistent: 

32 eigs2 = nsc_shift([(-d, d, 2)], h2.calc.dft)[0, 0] 

33 assert eigs2 == pytest.approx(eigs1) 

34 

35 # Check also fixed-density calculations: 

36 calc = h2.calc.fixed_density(kpts=[[0, 0, 0]]) 

37 eigs3 = calc.get_eigenvalues() 

38 assert eigs3 == pytest.approx(eigs1) 

39 

40 # SOC corrections: 

41 eigs4 = soc_eigenstates(calc).eigenvalues()[0] 

42 assert eigs4[::2] == pytest.approx(eigs1) 

43 assert eigs4[1::2] == pytest.approx(eigs1) 

44 

45 

46if __name__ == '__main__': 

47 test_scissors()