ASE Manual Release 3.6.1.2825 CAMd - CampOS Wiki

ASE Manual, Release 3.6.1.2828
nwannier: The number of Wannier functions you wish to construct. This must be at least
half the number of electrons in the system and at most equal to the number of bands in the
calculation.
calc: A converged DFT calculator class. If file arg. is not provided, the calculator must
provide the method get_wannier_localization_matrix, and contain the wavefunctions
(save files with only the density is not enough). If the localization matrix is read
from file, this is not needed, unless get_function or write_cube is called.
Optional arguments:
nbands: Bands to include in localization. The number of bands considered by Wannier can
be smaller than the number of bands in the calculator. This is useful if the highest bands of
the DFT calculation are not well converged.
spin: The spin channel to be considered. The Wannier code treats each spin channel independently.
fixedenergy / fixedstates: Fixed part of Heilbert space. Determine the fixed part of
Hilbert space by either a maximal energy or a number of bands (possibly a list for multiple
k-points). Default is None meaning that the number of fixed states is equated to nwannier.
file: Read localization and rotation matrices from this file.
initialwannier: Initial guess for Wannier rotation matrix. Can be ‘bloch’ to start from
the Bloch states, ‘random’ to be randomized, or a list passed to calc.get_initial_wannier.
seed: Seed for random initialwannier.
verbose: True / False level of verbosity.
get_centers(scaled=False)
Calculate the Wannier centers
pos = L / 2pi * phase(diag(Z))
get_function(index, repeat=None)
Get Wannier function on grid.
Returns an array with the funcion values of the indicated Wannier function on a grid with the size of
the repeated unit cell.
For a calculation using k-points the relevant unit cell for eg. visualization of the Wannier orbitals is
not the original unit cell, but rather a larger unit cell defined by repeating the original unit cell by the
number of k-points in each direction. Note that for a Γ-point calculation the large unit cell coinsides
with the original unit cell. The large unitcell also defines the periodicity of the Wannier orbitals.
index can be either a single WF or a coordinate vector in terms of the WFs.
get_functional_value()
Calculate the value of the spread functional.
Tr[|ZI|^2]=sum(I)sum(n) w_i|Z_(i)_nn|^2,
where w_i are weights.
get_hamiltonian(k=0)
Get Hamiltonian at existing k-vector of index k
dag
H(k) = V diag(eps ) V
k k k
get_hamiltonian_kpoint(kpt_c)
Get Hamiltonian at some new arbitrary k-vector
7.22. Density Functional Theory 159