The PAW calculator object¶

class
gpaw.calculator.
GPAW
(restart=None, ignore_bad_restart_file=False, label=None, atoms=None, timer=None, communicator=None, txt='', parallel=None, **kwargs)[source]¶ This is the ASEcalculator frontend for doing a PAW calculation.

add_wannier_correction
(Z_nn, G_c, u, u1, nbands=None)¶ Calculate the correction to the wannier integrals Z, given by (Eq. 27 ref1):
i G.r Z = <psi  e psi > nm n m __ __ ~ \ a \ a* a a Z = Z + ) exp[i G . R ] ) P dO P nmx nmx /__ x /__ ni ii' mi' a ii'
Note that this correction is an approximation that assumes the exponential varies slowly over the extent of the augmentation sphere.
ref1: Thygesen et al, Phys. Rev. B 72, 125119 (2005)

attach
(function, n=1, *args, **kwargs)¶ Register observer function.
Call function using args and kwargs as arguments.
If n is positive, then function will be called every n iterations + the final iteration if it would not be otherwise
If n is negative, then function will only be called on iteration abs(n).
If n is 0, then function will only be called on convergence

band_structure
()¶ Create bandstructure object for plotting.

calculate_numerical_forces
(atoms, d=0.001)¶ Calculate numerical forces using finite difference.
All atoms will be displaced by +d and d in all directions.

calculate_numerical_stress
(atoms, d=1e06, voigt=True)¶ Calculate numerical stress using finite difference.

call_observers
(iter, final=False)¶ Call all registered callback functions.

converge_wave_functions
()¶ Converge the wavefunctions if not present.

embed
(q_p, rc=0.2, rc2=inf, width=1.0)¶ Embed QM region in pointcharges.

estimate_memory
(mem)¶ Estimate memory use of this object.

get_all_electron_density
(spin=None, gridrefinement=2, pad=True, broadcast=True, collect=True, skip_core=False)¶ Return reconstructed allelectron density array.

get_all_electron_ldos
(mol, spin=0, npts=201, width=None, wf_k=None, P_aui=None, lc=None, raw=False)¶ The Projected Density of States, using allelectron wavefunctions.
Projects onto a pseudo_wavefunctions (wf_k) corresponding to some band n and uses P_aui ([paw.nuclei[a].P_uni[:,n,:] for a in atoms]) to obtain the allelectron overlaps. Instead of projecting onto a wavefunction, a molecular orbital can be specified by a linear combination of weights (lc)

get_bz_k_points
()¶ Return the kpoints.

get_bz_to_ibz_map
()¶ Return indices from BZ to IBZ.

get_dos
(spin=0, npts=201, width=None)¶ The total DOS.
Fold eigenvalues with Gaussians, and put on an energy grid.
returns an (energies, dos) tuple, where energies are relative to the vacuum level for nonperiodic systems, and the average potential for periodic systems.

get_effective_potential
(spin=0, pad=True, broadcast=True)¶ Return pseudo effectivepotential.

get_eigenvalues
(kpt=0, spin=0, broadcast=True)¶ Return eigenvalue array.

get_electrostatic_corrections
()¶ Calculate PAW correction to average electrostatic potential.

get_electrostatic_potential
()¶ Return the electrostatic potential.
This is the potential from the pseudo electron density and the PAWcompensation charges. So, the electrostatic potential will only be correct outside the PAW augmentation spheres.

get_fermi_level
()¶ Return the Fermilevel(s).

get_fermi_levels
()¶ Return the Fermilevels in case of fixedmagmom.

get_fermi_levels_mean
()¶ Return the mean of th Fermilevels in case of fixedmagmom.

get_fermi_splitting
()¶ Return the Fermilevelsplitting in case of fixedmagmom.

get_homo_lumo
(spin=None)¶ Return HOMO and LUMO eigenvalues.
By default, return the true HOMOLUMO eigenvalues (spin=None).
If spin is 0 or 1, return HOMOLUMO eigenvalues taken among only those states with the given spin.

get_ibz_k_points
()¶ Return kpoints in the irreducible part of the Brillouin zone.

get_k_point_weights
()¶ Weights of the kpoints.
The sum of all weights is one.

get_lcao_dos
(atom_indices=None, basis_indices=None, npts=201, width=None)¶ Get density of states projected onto orbitals in LCAO mode.
basis_indices is a list of indices of basis functions on which to project. To specify all basis functions on a set of atoms, you can supply atom_indices instead. Both cannot be given simultaneously.

get_magnetic_moments
(atoms=None)¶ Calculate magnetic moments projected onto atoms.

get_number_of_bands
()¶ Return the number of bands.

get_occupation_numbers
(kpt=0, spin=0, broadcast=True)¶ Return occupation array.

get_orbital_ldos
(a, spin=0, angular='spdf', npts=201, width=None, nbands=None, spinorbit=False)¶ The Local Density of States, using atomic orbital basis functions.
Project wave functions onto an atom orbital at atom
a
, and use this as weight when summing the eigenvalues.The atomic orbital has angular momentum
angular
, which can be ‘s’, ‘p’, ‘d’, ‘f’, or any combination (e.g. ‘sdf’).An integer value for
angular
can also be used to specify a specific projector function to project onto.Setting nbands limits the number of bands included. This speeds up the calculation if one has many bands in the calculator but is only interested in the DOS at low energies.

get_projections
(locfun, spin=0)¶ Project wave functions onto localized functions
Determine the projections of the KohnSham eigenstates onto specified localized functions of the format:
locfun = [[spos_c, l, sigma], [...]]
spos_c can be an atom index, or a scaled position vector. l is the angular momentum, and sigma is the (half) width of the radial gaussian.
Return format is:
f_kni = <psi_kn  f_i>
where psi_kn are the wave functions, and f_i are the specified localized functions.
As a special case, locfun can be the string ‘projectors’, in which case the bound state projectors are used as localized functions.

get_pseudo_density
(spin=None, gridrefinement=1, pad=True, broadcast=True)¶ Return pseudodensity array.
If spin is not given, then the total density is returned. Otherwise, the spin up or down density is returned (spin=0 or 1).

get_pseudo_density_corrections
()¶ Integrated density corrections.
Returns the integrated value of the difference between the pseudo and the allelectron densities at each atom. These are the numbers you should add to the result of doing e.g. Bader analysis on the pseudo density.

get_pseudo_valence_density
(spin=None, gridrefinement=1, pad=True, broadcast=True)¶ Return pseudodensity array.
If spin is not given, then the total density is returned. Otherwise, the spin up or down density is returned (spin=0 or 1).

get_pseudo_wave_function
(band=0, kpt=0, spin=0, broadcast=True, pad=True, periodic=False)¶ Return pseudowavefunction array.
Units: 1/Angstrom^(3/2)

get_spin_polarized
()¶ Is it a spinpolarized calculation?

get_wannier_integrals
(s, k, k1, G_c, nbands=None)¶ Calculate integrals for maximally localized Wannier functions.

get_wannier_localization_matrix
(nbands, dirG, kpoint, nextkpoint, G_I, spin)¶ Calculate integrals for maximally localized Wannier functions.

get_wigner_seitz_densities
(spin)¶ Get the weight of the spindensity in WignerSeitz cells around each atom.
The density assigned to each atom is relative to the neutral atom, i.e. the density sums to zero.

get_wigner_seitz_ldos
(a, spin=0, npts=201, width=None)¶ The Local Density of States, using a WignerSeitz basis function.
Project wave functions onto a WignerSeitz box at atom
a
, and use this as weight when summing the eigenvalues.

get_xc_functional
()¶ Return the XCfunctional identifier.
‘LDA’, ‘PBE’, …

initial_wannier
(initialwannier, kpointgrid, fixedstates, edf, spin, nbands)¶ Initial guess for the shape of wannier functions.
Use initial guess for wannier orbitals to determine rotation matrices U and C.

linearize_to_xc
(newxc)¶ Linearize Hamiltonian to difference XC functional.
Used in real time TDDFT to perform calculations with various kernels.

print_memory_estimate
(log=None, maxdepth=1)¶ Print estimated memory usage for PAW object and components.
maxdepth is the maximum nesting level of displayed components.
The PAW object must be initialize()’d, but needs not have large arrays allocated.

read
(filename)[source]¶ Read atoms, parameters and calculated properties from output file.
Read result from self.label file. Raise ReadError if the file is not there. If the file is corrupted or contains an error message from the calculation, a ReadError should also be raised. In case of succes, these attributes must set:
 atoms: Atoms object
 The state of the atoms from last calculation.
 parameters: Parameters object
 The parameter dictionary.
 results: dict
 Calculated properties like energy and forces.
The FileIOCalculator.read() method will typically read atoms and parameters and get the results dict by calling the read_results() method.

reset
()¶ Clear all information from old calculation.

set
(**kwargs)[source]¶ Change parameters for calculator.
Examples:
calc.set(xc='PBE') calc.set(nbands=20, kpts=(4, 1, 1))

set_label
(label)¶ Set label and convert label to directory and prefix.
Examples:
 label=’abc’: (directory=’.’, prefix=’abc’)
 label=’dir1/abc’: (directory=’dir1’, prefix=’abc’)
Calculators that must write results to files with fixed names can overwrite this method so that the directory is set to all of label.


class
gpaw.paw.
PAW
[source]¶ ASEcalculator interface.
The following parameters can be used: nbands, xc, kpts, kpt_refine, spinpol, gpts, h, charge, symmetry, width, mixer, hund, lmax, fixdensity, convergence, txt, parallel, communicator, dtype, softgauss and stencils.
If you don’t specify any parameters, you will get:
Defaults: neutrally charged, LDA, gammapoint calculation, a reasonable gridspacing, zero Kelvin electronic temperature, and the number of bands will be equal to the number of atomic orbitals present in the setups. Only occupied bands are used in the convergence decision. The calculation will be spinpolarized if and only if one or more of the atoms have nonzero magnetic moments. Text output will be written to standard output.
For a nongamma point calculation, the electronic temperature will be 0.1 eV (energies are extrapolated to zero Kelvin) and all symmetries will be used to reduce the number of kpoints.

add_wannier_correction
(Z_nn, G_c, u, u1, nbands=None)[source]¶ Calculate the correction to the wannier integrals Z, given by (Eq. 27 ref1):
i G.r Z = <psi  e psi > nm n m __ __ ~ \ a \ a* a a Z = Z + ) exp[i G . R ] ) P dO P nmx nmx /__ x /__ ni ii' mi' a ii'
Note that this correction is an approximation that assumes the exponential varies slowly over the extent of the augmentation sphere.
ref1: Thygesen et al, Phys. Rev. B 72, 125119 (2005)

attach
(function, n=1, *args, **kwargs)[source]¶ Register observer function.
Call function using args and kwargs as arguments.
If n is positive, then function will be called every n iterations + the final iteration if it would not be otherwise
If n is negative, then function will only be called on iteration abs(n).
If n is 0, then function will only be called on convergence

get_all_electron_density
(spin=None, gridrefinement=2, pad=True, broadcast=True, collect=True, skip_core=False)[source]¶ Return reconstructed allelectron density array.

get_all_electron_ldos
(mol, spin=0, npts=201, width=None, wf_k=None, P_aui=None, lc=None, raw=False)[source]¶ The Projected Density of States, using allelectron wavefunctions.
Projects onto a pseudo_wavefunctions (wf_k) corresponding to some band n and uses P_aui ([paw.nuclei[a].P_uni[:,n,:] for a in atoms]) to obtain the allelectron overlaps. Instead of projecting onto a wavefunction, a molecular orbital can be specified by a linear combination of weights (lc)

get_dos
(spin=0, npts=201, width=None)[source]¶ The total DOS.
Fold eigenvalues with Gaussians, and put on an energy grid.
returns an (energies, dos) tuple, where energies are relative to the vacuum level for nonperiodic systems, and the average potential for periodic systems.

get_effective_potential
(spin=0, pad=True, broadcast=True)[source]¶ Return pseudo effectivepotential.

get_electrostatic_corrections
()[source]¶ Calculate PAW correction to average electrostatic potential.

get_electrostatic_potential
()[source]¶ Return the electrostatic potential.
This is the potential from the pseudo electron density and the PAWcompensation charges. So, the electrostatic potential will only be correct outside the PAW augmentation spheres.

get_homo_lumo
(spin=None)[source]¶ Return HOMO and LUMO eigenvalues.
By default, return the true HOMOLUMO eigenvalues (spin=None).
If spin is 0 or 1, return HOMOLUMO eigenvalues taken among only those states with the given spin.

get_lcao_dos
(atom_indices=None, basis_indices=None, npts=201, width=None)[source]¶ Get density of states projected onto orbitals in LCAO mode.
basis_indices is a list of indices of basis functions on which to project. To specify all basis functions on a set of atoms, you can supply atom_indices instead. Both cannot be given simultaneously.

get_orbital_ldos
(a, spin=0, angular='spdf', npts=201, width=None, nbands=None, spinorbit=False)[source]¶ The Local Density of States, using atomic orbital basis functions.
Project wave functions onto an atom orbital at atom
a
, and use this as weight when summing the eigenvalues.The atomic orbital has angular momentum
angular
, which can be ‘s’, ‘p’, ‘d’, ‘f’, or any combination (e.g. ‘sdf’).An integer value for
angular
can also be used to specify a specific projector function to project onto.Setting nbands limits the number of bands included. This speeds up the calculation if one has many bands in the calculator but is only interested in the DOS at low energies.

get_projections
(locfun, spin=0)[source]¶ Project wave functions onto localized functions
Determine the projections of the KohnSham eigenstates onto specified localized functions of the format:
locfun = [[spos_c, l, sigma], [...]]
spos_c can be an atom index, or a scaled position vector. l is the angular momentum, and sigma is the (half) width of the radial gaussian.
Return format is:
f_kni = <psi_kn  f_i>
where psi_kn are the wave functions, and f_i are the specified localized functions.
As a special case, locfun can be the string ‘projectors’, in which case the bound state projectors are used as localized functions.

get_pseudo_density
(spin=None, gridrefinement=1, pad=True, broadcast=True)[source]¶ Return pseudodensity array.
If spin is not given, then the total density is returned. Otherwise, the spin up or down density is returned (spin=0 or 1).

get_pseudo_density_corrections
()[source]¶ Integrated density corrections.
Returns the integrated value of the difference between the pseudo and the allelectron densities at each atom. These are the numbers you should add to the result of doing e.g. Bader analysis on the pseudo density.

get_pseudo_valence_density
(spin=None, gridrefinement=1, pad=True, broadcast=True)¶ Return pseudodensity array.
If spin is not given, then the total density is returned. Otherwise, the spin up or down density is returned (spin=0 or 1).

get_pseudo_wave_function
(band=0, kpt=0, spin=0, broadcast=True, pad=True, periodic=False)[source]¶ Return pseudowavefunction array.
Units: 1/Angstrom^(3/2)

get_wannier_integrals
(s, k, k1, G_c, nbands=None)[source]¶ Calculate integrals for maximally localized Wannier functions.

get_wannier_localization_matrix
(nbands, dirG, kpoint, nextkpoint, G_I, spin)[source]¶ Calculate integrals for maximally localized Wannier functions.

get_wigner_seitz_densities
(spin)[source]¶ Get the weight of the spindensity in WignerSeitz cells around each atom.
The density assigned to each atom is relative to the neutral atom, i.e. the density sums to zero.

get_wigner_seitz_ldos
(a, spin=0, npts=201, width=None)[source]¶ The Local Density of States, using a WignerSeitz basis function.
Project wave functions onto a WignerSeitz box at atom
a
, and use this as weight when summing the eigenvalues.

initial_wannier
(initialwannier, kpointgrid, fixedstates, edf, spin, nbands)[source]¶ Initial guess for the shape of wannier functions.
Use initial guess for wannier orbitals to determine rotation matrices U and C.
