tools: Remove DOS function

* Not used

CHANGELOG.md

@@ -45,7 +45,6 @@ v2.7.0 - Jan 19, 2024
    - Small performance improvements, e.g, in Atoms object creation
 - Experimental
    - Smearing functionalities
-   - Density of states function
 
 ----
 

eminus/tools.py

@@ -501,34 +501,3 @@ def electronic_entropy(E, mu, kbT):
         return 0
     f = fermi_distribution(E, mu, kbT)
     return f * np.log(f) + (1 - f) * np.log(1 - f)
-
-
-def get_dos(epsilon, wk, spin=0, npts=201, width=0.1):
-    """Calculate the total density of states.
-
-    Reference: https://gitlab.com/gpaw/gpaw/-/blob/master/gpaw/calculator.py
-
-    Args:
-        epsilon (ndarray): Eigenenergies.
-        wk (ndarray): Chemical energy or Fermi energy.
-
-    Keyword Args:
-        spin (int): Spin channel.
-        npts (int): Number of energy discretizations.
-        width (float): Gaussian width.
-
-    Returns:
-        tuple[ndarray, ndarray]: Eigenenergies and DOS.
-    """
-    def delta(x, x0, width):
-        """Gaussian of given width centered at x0."""
-        return np.exp(np.clip(-((x - x0) / width)**2, -100, 100)) / (np.sqrt(np.pi) * width)
-
-    energies = epsilon[:, spin].flatten()
-    emin = np.min(energies) - 5 * width
-    emax = np.max(energies) + 5 * width
-    e = np.linspace(emin, emax, npts)
-    dos_e = np.zeros(npts)
-    for e0, w in zip(energies, wk):
-        dos_e += w * delta(e, e0, width)
-    return e, dos_e