Magnetism¶

class py4vasp.data.Magnetism(*args, **kwargs)¶

Bases: Mixin, Refinery, Mixin

The magnetic moments and localized charges for selected ionic steps.

This class gives access to the magnetic moments and charges projected on the different orbitals on every atom.

Examples

If you access a method of this class, the result will depend on the steps that you selected with the [] operator. Without any selection the results from the final step will be used.

>>> calc.magnetism.read()

To select the results for all steps, you don’t specify the array boundaries.

>>> calc.magnetism[:].read()

You can also select specific steps or a subset of steps as follows

>>> calc.magnetism[5].read()
>>> calc.magnetism[1:6].read()

Attributes Summary

length_moments	Length in Å how a magnetic moment is displayed relative to the largest moment.
path	Returns the path from which the output is obtained.

Methods Summary

charges()	Read the charges of the selected steps.
from_data(raw_data)	Create the instance directly from the raw data.
from_file(file)	Read the quantities from the given file.
from_path([path])	Read the quantities from the given path.
moments()	Read the magnetic moments of the selected steps.
plot()	Visualize the magnetic moments as arrows inside the structure.
print()	Print a string representation of this instance.
read(*args, **kwargs)	Convenient wrapper around to_dict.
to_dict()	Read the charges and magnetization data into a dictionary.
total_charges()	Read the total charges of the selected steps.
total_moments()	Read the total magnetic moments of the selected steps.

Attributes Documentation

length_moments = 1.5¶

Length in Å how a magnetic moment is displayed relative to the largest moment.

path¶

Returns the path from which the output is obtained.

Methods Documentation

charges()¶

Read the charges of the selected steps.

Returns:

Contains the charges for the selected steps projected on atoms and orbitals.

Return type:

np.ndarray

Examples

If you access this method, the result will depend on the steps of the class that you selected with the [] operator. Without any selection the results from the final step will be used.

>>> calc.magnetism.charges()

To select the results for all steps, you don’t specify the array boundaries.

>>> calc.magnetism[:].charges()

You can also select specific steps or a subset of steps as follows

>>> calc.magnetism[5].charges()
>>> calc.magnetism[1:6].charges()

classmethod from_data(raw_data)¶

Create the instance directly from the raw data.

Use this approach when the data is put into the correct format by other means than reading from the VASP output files. A typical use case is to read the data with from_path and then act on it with some postprocessing and pass the results to this method.

Parameters:

raw_data – The raw data required to produce this Refinery.

Return type:

A Refinery instance to handle the passed data.

classmethod from_file(file)¶

Read the quantities from the given file.

You want to use this method if you want to avoid using the Calculation wrapper, for example because you renamed the output of the VASP calculation.

Parameters:

file (str or io.BufferedReader) – Filename from which the data is extracted. Alternatively, you can open the file yourself and pass the Reader object. In that case, you need to take care the file is properly closed again and be aware the generated instance of this class becomes unusable after the file is closed.

Returns:

The returned instance handles opening and closing the file for every function called on it, unless a Reader object is passed in which case this is left to the user.

Return type:

Refinery

Notes

VASP produces multiple output files whereas this routine will only link to the single specified file. Prefer from_path routine over this method unless you renamed the VASP output files, because from_path can collate results from multiple files.

classmethod from_path(path=None)¶

Read the quantities from the given path.

The VASP schema determines the particular files accessed. The files will only be accessed when the data is required for a particular postprocessing call.

Parameters:

path (str or pathlib.Path) – Path to the directory with the outputs of the VASP calculation. If not set explicitly the current directory will be used.

Returns:

The returned instance handles opening and closing the files for every function called on it.

Return type:

Refinery

moments()¶

Read the magnetic moments of the selected steps.

Returns:

Contains the magnetic moments for the selected steps projected on atoms and orbitals.

Return type:

np.ndarray

Notes

The index order is different compared to the raw data when noncollinear calculations are used. This routine returns the magnetic moments as (steps, atoms, orbitals, directions).

Examples

If you access this method, the result will depend on the steps of the class that you selected with the [] operator. Without any selection the results from the final step will be used.

>>> calc.magnetism.moments()

To select the results for all steps, you don’t specify the array boundaries.

>>> calc.magnetism[:].moments()

You can also select specific steps or a subset of steps as follows

>>> calc.magnetism[5].moments()
>>> calc.magnetism[1:6].moments()

plot()¶

Visualize the magnetic moments as arrows inside the structure.

Returns:

Contains the atoms and the unit cell as well as an arrow indicating the strength of the magnetic moment. If noncollinear magnetism is used the moment points in the actual direction; for collinear magnetism the moments are aligned along the z axis by convention.

Return type:

Viewer3d

Examples

If you access this method, the result will depend on the steps of the class that you selected with the [] operator. Without any selection the results from the final step will be used.

>>> calc.magnetism.to_graph()

To select the results for all steps, you don’t specify the array boundaries.

>>> calc.magnetism[:].to_graph()

You can also select specific steps or a subset of steps as follows

>>> calc.magnetism[5].to_graph()
>>> calc.magnetism[1:6].to_graph()

print()¶

Print a string representation of this instance.

read(*args, **kwargs)¶

Convenient wrapper around to_dict. Check that function for examples and optional arguments.

to_dict()¶

Read the charges and magnetization data into a dictionary.

Returns:

Contains the charges and magnetic moments generated by VASP projected on atoms and orbitals.

Return type:

dict

Notes

The index order is different compared to the raw data when noncollinear calculations are used. This routine returns the magnetic moments as (steps, atoms, orbitals, directions).

Examples

If you access this method, the result will depend on the steps of the class that you selected with the [] operator. Without any selection the results from the final step will be used.

>>> calc.magnetism.to_dict()

To select the results for all steps, you don’t specify the array boundaries.

>>> calc.magnetism[:].to_dict()

You can also select specific steps or a subset of steps as follows

>>> calc.magnetism[5].to_dict()
>>> calc.magnetism[1:6].to_dict()

total_charges()¶

Read the total charges of the selected steps.

Returns:

Contains the total charges for the selected steps projected on atoms. This corresponds to the charges summed over the orbitals.

Return type:

np.ndarray

Examples

If you access this method, the result will depend on the steps of the class that you selected with the [] operator. Without any selection the results from the final step will be used.

>>> calc.magnetism.total_charges()

To select the results for all steps, you don’t specify the array boundaries.

>>> calc.magnetism[:].total_charges()

You can also select specific steps or a subset of steps as follows

>>> calc.magnetism[5].total_charges()
>>> calc.magnetism[1:6].total_charges()

total_moments()¶

Read the total magnetic moments of the selected steps.

Returns:

Contains the total magnetic moments for the selected steps projected on atoms. This corresponds to the magnetic moments summed over the orbitals.

Return type:

np.ndarray

Notes

The index order is different compared to the raw data when noncollinear calculations are used. This routine returns the magnetic moments as (steps, atoms, orbitals, directions).

Examples

If you access this method, the result will depend on the steps of the class that you selected with the [] operator. Without any selection the results from the final step will be used.

>>> calc.magnetism.total_moments()

To select the results for all steps, you don’t specify the array boundaries.

>>> calc.magnetism[:].total_moments()

You can also select specific steps or a subset of steps as follows

>>> calc.magnetism[5].total_moments()
>>> calc.magnetism[1:6].total_moments()