Coverage for gpaw/test/lrtddft/test_2.py: 100%

1import pytest 

2from ase import Atoms 

3from gpaw import GPAW 

4from gpaw.lrtddft import LrTDDFT 

5from gpaw.lrtddft.spectrum import spectrum 

6 

7 

8@pytest.mark.lrtddft 

9def test_lrtddft_2(in_tmp_dir): 

10 txt = None 

11 xc = 'LDA' 

12 

13 R = 0.7 # approx. experimental bond length 

14 a = 4.0 

15 c = 5.0 

16 H2 = Atoms('HH', 

17 [(a / 2, a / 2, (c - R) / 2), 

18 (a / 2, a / 2, (c + R) / 2)], 

19 cell=(a, a, c)) 

20 

21 calc = GPAW(mode='fd', 

22 xc=xc, 

23 nbands=2, 

24 spinpol=False, 

25 eigensolver='rmm-diis', 

26 txt=txt) 

27 H2.calc = calc 

28 H2.get_potential_energy() 

29 calc.write('H2saved_wfs.gpw', 'all') 

30 calc.write('H2saved.gpw') 

31 

32 print('-> starting directly after a gs calculation') 

33 lr = LrTDDFT(calc, txt='-') 

34 lr.diagonalize() 

35 

36 print('-> reading gs with wfs') 

37 gs = GPAW('H2saved_wfs.gpw', txt=txt) 

38 

39 lr1 = LrTDDFT(gs, xc=xc, txt='-') 

40 # check the oscillator strength 

41 assert (abs(lr1[0].get_oscillator_strength()[0] / 

42 lr[0].get_oscillator_strength()[0] - 1) < 1e-7) 

43 

44 print('-> reading gs without wfs') 

45 gs = GPAW('H2saved.gpw', txt=None) 

46 

47 lr2 = LrTDDFT(gs, txt='-') 

48 # check the oscillator strrength 

49 d = abs(lr2[0].get_oscillator_strength()[0] / 

50 lr[0].get_oscillator_strength()[0] - 1) 

51 assert (d < 2e-3), d 

52 

53 # write spectrum 

54 spectrum(lr, 'spectrum.dat')