Source code for ase.dft.dos
from math import pi, sqrt
import numpy as np
[docs]class DOS:
def __init__(self, calc, width=0.1, window=None, npts=201):
"""Electronic Density Of States object.
calc: calculator object
Any ASE compliant calculator object.
width: float
Width of guassian smearing.
window: tuple of two float
Use ``window=(emin, emax)``. If not specified, a window
big enough to hold all the eigenvalues will be used.
npts: int
Number of points.
"""
self.npts = npts
self.width = width
self.w_k = calc.get_k_point_weights()
self.nspins = calc.get_number_of_spins()
self.e_skn = np.array([[calc.get_eigenvalues(kpt=k, spin=s)
for k in range(len(self.w_k))]
for s in range(self.nspins)])
self.e_skn -= calc.get_fermi_level()
if window is None:
emin = self.e_skn.min() - 5 * self.width
emax = self.e_skn.max() + 5 * self.width
else:
emin, emax = window
self.energies = np.linspace(emin, emax, npts)
[docs] def get_energies(self):
"""Return the array of energies used to sample the DOS. The energies are reported relative to the Fermi level."""
return self.energies
def delta(self, energy):
"""Return a delta-function centered at 'energy'."""
x = -((self.energies - energy) / self.width)**2
return np.exp(x) / (sqrt(pi) * self.width)
[docs] def get_dos(self, spin=None):
"""Get array of DOS values.
The *spin* argument can be 0 or 1 (spin up or down) - if not
specified, the total DOS is returned.
"""
if spin is None:
if self.nspins == 2:
# Spin-polarized calculation, but no spin specified -
# return the total DOS:
return self.get_dos(spin=0) + self.get_dos(spin=1)
else:
spin = 0
dos = np.zeros(self.npts)
for w, e_n in zip(self.w_k, self.e_skn[spin]):
for e in e_n:
dos += w * self.delta(e)
return dos