def test_fermi_energy_spin_saturated(self):
""" This is to test the determination of Fermi level"""
ee = np.arange(-10.13, 100.0, 0.1)
#print('0: ', ee.shape)
nelec = 5.0
telec = 0.01
fermi_energy = get_fermi_energy(ee, nelec, telec)
occ = 2.0*fermi_dirac_occupations(telec, ee, fermi_energy)
self.assertAlmostEqual(occ.sum(), 5.0)
self.assertAlmostEqual(fermi_energy, -9.93)
def test_fermi_energy_spin_resolved_spin1(self):
""" This is to test the determination of Fermi level"""
ee = np.linspace(-10.13, 99.97, 1102).reshape((1,1102))
#print('1: ', ee.shape)
nelec = 5.0
telec = 0.01
fermi_energy = get_fermi_energy(ee, nelec, telec)
occ = 2.0*fermi_dirac_occupations(telec, ee, fermi_energy)
self.assertAlmostEqual(occ.sum(), 5.0)
self.assertAlmostEqual(fermi_energy, -9.93)
def test_fermi_energy_spin_resolved_even(self):
""" This is to test the determination of Fermi level in spin-resolved case"""
ee = np.row_stack((np.linspace(-10.3, 100.0, 1003), np.linspace(-10.0, 100.0, 1003)))
nelec = 20.0
telec = 0.02
#print(ee)
fermi_energy = get_fermi_energy(ee, nelec, telec)
occ = fermi_dirac_occupations(telec, ee, fermi_energy)
self.assertAlmostEqual(occ.sum(), 20.0)
self.assertAlmostEqual(fermi_energy, -9.10544404859)
def test_fermi_energy_spin_resolved_even_kpoints_spin2(self):
""" This is to test the determination of Fermi level in spin-resolved case"""
ee = np.row_stack((np.linspace(-10.1, 100.0, 1003),
np.linspace(-10.2, 100.0, 1003),
np.linspace(-10.3, 100.0, 1003),
np.linspace(-10.4, 100.0, 1003))).reshape((2,2,1003))
nelec = 20.0
telec = 0.02
nkpts = ee.shape[0]
nspin = ee.shape[-2]
#print(ee)
fermi_energy = get_fermi_energy(ee, nelec, telec)
occ = (3.0-nspin)*fermi_dirac_occupations(telec, ee, fermi_energy)
#print(occ)
#print(occ.sum()/nkpts)
#print(fermi_energy)
self.assertAlmostEqual(occ.sum()/nkpts, 20.0)
self.assertAlmostEqual(fermi_energy, -9.2045998319213016)