NEW! Wannierisation inside WannierBerri

Now WannierBerri can construct wannier functions on its own. Both disentanglement and localisation.

Wannierisation can be performed with both sitesym=True and frozen window (this feature is currently not available in Wannier90).

see examples in examples/wannierise+sitesym-Fe and examples/wannierise+sitesym-diamond

wannierise.wannierise(froz_min=inf, froz_max=-inf, num_iter=1000, conv_tol=1e-09, num_iter_converge=3, mix_ratio_z=0.5, mix_ratio_u=1, print_progress_every=10, sitesym=False, localise=True, init='amn', num_wann=None, parallel=True, symmetrize_Z=True)

Performs disentanglement and maximal localization of the bands recorded in w90data. The disentanglement is done following the procedure described in Souza et al., PRB 2001. The localization is done following a simplified procedure, avoiding gradient descent of the spread functional.

At the end writes w90data.chk.v_matrix and sets w90data.wannierised = True

Parameters:

  • w90data (Wannier90data) – the data

  • froz_min (float) – lower bound of the frozen window

  • froz_max (float) – upper bound of the frozen window

  • num_iter (int) – maximal number of iterations.

  • conv_tol (float) – tolerance for convergence of the spread functional (in \(\mathring{\rm A}^{2}\))

  • num_iter_converge (int) – the convergence is achieved when the standard deviation of the spread functional over the num_iter_converge*print_progress_every iterations is less than conv_tol

  • mix_ratio_z (float) – 0 <= mix_ratio_z <=1 - mixing the Z matrix (disentanglement) from previous itertions. 1 for max speed, smaller values are more stable

  • mix_ratio_u (float) – 0 <= mix_ratio_u <=1 - mixing the U matrix (localization) from previous itertions. 1 for max speed, smaller values are more stable WARNING : u<1 at the moment may lead to non-convergence. It is recommended to use mix_ratio_u=1 for now.

  • print_progress_every – frequency to print the progress

  • sitesym (bool) – whether to use the site symmetry (Symmetry-adapted Wannier Functions). If True, the symmetrizer attribute should be present in the w90data (either from pw2wannier90 or generated by wabnnierberri see SymmetrizerSAWF, from_irrep() and set_D_wann_from_projections()

  • localise (bool) – whether to perform the localization. If False, only disentanglement and rotation to projections are performed

  • kwargs_sitesym (dict) – additional the keyword arguments to be passed to the constructor of the Symmetrizer

  • init (str) – the initialization of the U matrix. “amn” for the current state, “random” for random initialization, “restart” for restarting from the previous state

  • num_wann (int) – the number of Wannier functions. Required for random initialization only without sitesymmetry

  • parallel (bool) – if True - tries to run in parallel using ray. ray should be initialized before calling this function. If it was not initialized, the function will run in serial mode

  • symmetrize_Z (bool) – whether to symmetrize the disentangled Z matrix. If False, the Z matrix is not symmetrized which may lead to inaccuracy and slower convergence, but may be a faster calculation. Use it on your own risk.

Returns:

w90data.chk.v_matrix – the optimized U matrices

Return type:

numpy.ndarray

Note

  • Also sets the following attributes of chk:
    • w90data.chk.v_matrixnumpy.ndarray

      the optimized U matrices

    • w90data.wannierisedbool

      True

    • w90data.chk.wannier_centers_cartnumpy.ndarray (nW,3)

      the centers of the Wannier functions

    • w90data.chk.wannier_spreadsnumpy.ndarray (nW)

      the spreads of the Wannier functions

  • If the outer window is needed, use select_bands() before calling this function.

  • The function is not parallelized yet

  • Disentanglement and localization are done in the irreducible BZ (if sitesym=True) and then symmetrized to the full BZ

  • Disentanglement and localization are done together, in the same loop. Therefore only one parameter num_iter is used for both

Example

# This tutorial shows how to generate a DMN file inside Wanier Berri code (without pw2wannier90)
# and then use it to generate a Wannier90 output.
# It may be used with any DFT code that is supported by IrRep (QE, VASP, AINIT, ...)
# the .dmn and .amn files are NOT needed before the calculation, they is generated on the fly

from wannierberri.symmetry.projections import Projection, ProjectionsSet
from irrep.bandstructure import BandStructure
import wannierberri as wb

path_data = "../../tests/data/Fe-222-pw/"
w90data = wb.w90files.Wannier90data(seedname=path_data + "Fe", readfiles=["mmn", "eig", "win", ], read_npz=True)


bandstructure = BandStructure(code='espresso',
                           prefix=path_data + "/Fe",
                           Ecut=200,
                           normalize=True,
                           magmom=[[0, 0, 1.]],
                           include_TR=True,
                           )
spacegroup = bandstructure.spacegroup
spacegroup.show()
# exit()
# symmetrizer = wb.symmetry.sawf.SymmetrizerSAWF().from_npz(path_data + f"/Fe_TR={False}.sawf.npz")
symmetrizer = wb.symmetry.sawf.SymmetrizerSAWF().from_irrep(bandstructure)

projection_s = Projection(orbital='s', position_num=[0, 0, 0], spacegroup=spacegroup)
projection_p = Projection(orbital='p', position_num=[0, 0, 0], spacegroup=spacegroup)
projection_d = Projection(orbital='d', position_num=[0, 0, 0], spacegroup=spacegroup)
projection_sp3d2 = Projection(orbital='sp3d2', position_num=[0, 0, 0], spacegroup=spacegroup)
projection_t2g = Projection(orbital='t2g', position_num=[0, 0, 0], spacegroup=spacegroup)

# projections_set = ProjectionsSet(projections=[projection_s, projection_p, projection_d])
projections_set = ProjectionsSet(projections=[projection_sp3d2, projection_t2g])

symmetrizer.set_D_wann_from_projections(projections_set)
amn = wb.w90files.amn_from_bandstructure(bandstructure, projections=projections_set)
w90data.set_symmetrizer(symmetrizer)
w90data.set_file("amn", amn)

w90data.select_bands(win_min=-8, win_max=50)

w90data.wannierise(init="amn",
                  froz_min=-10,
                  froz_max=20,
                  print_progress_every=10,
                  num_iter=101,
                  conv_tol=1e-10,
                  mix_ratio_z=1.0,
                  sitesym=True,
                  parallel=False
                  )

system = wb.system.System_w90(w90data=w90data, berry=True)
# Now do whatever you want with the system, as if it was created with Wannier90