py4vasp.calculation ¶
Provide refinement functions for a the raw data of a VASP calculation run in the current directory.
Usually one is not directly interested in the raw data that is produced but wants to produce either a figure for a publication or some post-processing of the data. calculation contains multiple quantities that enable these kinds of workflows by extracting the relevant data from the HDF5 file and transforming them into an accessible format.
Generally, all quantities provide a read function that extracts the data from the HDF5 file and puts it into a Python dictionary. Where it makes sense in addition a plot function is available that converts the data into a figure for Jupyter notebooks. In addition, data conversion routines to_X may be available transforming the data into another format or file, which may be useful to generate plots with tools other than Python. For the specifics, please refer to the documentation of the individual quantities.
calculation reads the raw data from the current directory and from the default
VASP output files. With the Calculation class, you can tailor
the location of the files to your needs and both have access to the same quantities.
We demonstrate this setting up some example data in a temporary directory path and changing to it.
>>> import os
>>> from py4vasp import demo
>>> _ = demo.calculation(path)
>>> os.chdir(path) # change to a temporary directory
Then the two following examples are equivalent:
using calculation object
>>> from py4vasp import calculation
>>> calculation.dos.read()
{'energies': array(...), 'total': array(...), 'fermi_energy': ...}
using Calculation class
>>> from py4vasp import Calculation
>>> calculation = Calculation.from_path(".")
>>> calculation.dos.read()
{'energies': array(...), 'total': array(...), 'fermi_energy': ...}
In the latter example, you could directly provide a path and do not need to have the data in the current directory.
Available quantities
band- The band structure contains the k point resolved eigenvalues.
bandgap- This class describes the band extrema during the relaxation or MD simulation.
born_effective_charge- The Born effective charge tensors couple electric field and atomic displacement.
current_density- Represents current density on the grid in the unit cell.
density- This class accesses various densities (charge, magnetization, …) of VASP.
dielectric_function- The dielectric function describes the material response to an electric field.
dielectric_tensor- The dielectric tensor is the static limit of the
dielectric function. dos- The density of states (DOS) describes the number of states per energy.
effective_coulomb- Effective Coulomb interaction U obtained with the constrained random phase approximation (cRPA).
elastic_modulus- The elastic modulus is the second derivative of the energy with respect to strain.
electron_phonon.bandgap- ElectronPhononBandgap provides access to the electron-phonon bandgap renormalization data and selection utilities.
electron_phonon.chemical_potential- Provides access to the electron-phonon chemical potential data calculated during an electron-phonon calculation.
electron_phonon.self_energy- Access and analyze electron-phonon self-energy data.
electron_phonon.transport- Provides access to electron-phonon transport data and selection utilities.
electronic_minimization- Access the convergence data for each electronic step.
energy- The energy data for one or several steps of a relaxation or MD simulation.
exciton.density- This class accesses exciton charge densities of VASP.
exciton.eigenvector- BSE can compute excitonic properties of materials.
force- The forces determine the path of the atoms in a trajectory.
force_constant- Force constants are the 2nd derivatives of the energy with respect to displacement.
internal_strain- The internal strain is the derivative of energy with respect to displacement and strain.
kpoint- The k-point mesh used in the VASP calculation.
local_moment- The local moments describe the charge and magnetization near an atom.
nics- This class accesses information on the nucleus-independent chemical shift (NICS).
pair_correlation- The pair-correlation function measures the distribution of atoms.
partial_density- Partial charges describe the fraction of the charge density in a certain energy, band, or k-point range.
phonon.band- The phonon band structure contains the q-resolved phonon eigenvalues.
phonon.dos- The phonon density of states (DOS) describes the number of modes per energy.
phonon.mode- Describes a collective vibration of atoms in a crystal.
piezoelectric_tensor- The piezoelectric tensor is the derivative of the energy with respect to strain and field.
polarization- The static polarization describes the electric dipole moment per unit volume.
potential- The local potential describes the interactions between electrons and ions.
projector- The projectors used for atom and orbital resolved quantities.
run_info- Contains information about the VASP run.
stress- The stress describes the force acting on the shape of the unit cell.
structure- The structure contains the unit cell and the position of all ions within.
system- The SYSTEM tag in the INCAR file is a title you choose for a VASP calculation.
velocity- The velocities describe the ionic motion during an MD simulation.
workfunction- The workfunction describes the energy required to remove an electron to the vacuum.