# Documentation of the parsed outputs of the aiida-wannier90 plugin¶

This is the list of output parsed nodes.

## output_parameters¶

A Dict node (accessed by calculation.res). Contains a number of parsed properties. Currently it includes:

• number_wfs: the number of Wannier functions.

• Omega_D, Omega_I, Omega_OD, Omega_total: the components of the spread. They contain, respectively, the diagonal part $$\Omega_D$$, the gauge-invariant part $$\Omega_I$$, the off-diagonal part $$\Omega_{OD}$$, and the total spread $$\Omega_{total}$$. Units are always $$\mathring{A}^2$$.

• wannier_functions_output: a list of dictionaries containing:

• wf_ids: integer index of the Wannier functions

• wf_centres: the centre of the Wannier functions, in $$\mathring{A}$$.

• wf_spreads: the spread of the wannier functions, in $$\mathring{A}^2$$.

• im_re_ratio: if available, the Imaginary/Real ratio of the Wannier functions.

• warnings: parsed list of warnings (see section Warnings).

• length_units: units used to express the lengths. If these are not $$\mathring{A}$$, a warning will be added to the warnings list.

• output_verbosity: the output verbosity. A warning is thrown if any value other than the default is used.

• preprocess_only: whether the calculation only performed the preprocessing step (wannier90 -pp).

• r2mn_writeout: whether the $$r^2_{mn}$$ file was written.

• convergence_tolerance: the tolerance for convergence on the spread, in units of $$\mathring{A}^2$$.

• xyz_writeout: whether the xyz_wf_centre file was explicitly written.

• Other parameters, if present, should match those described in the user guide.

## interpolated_bands¶

A BandsData node. If a band structure is required, it will contain the bands interpolated using Wannier functions.

## Warnings¶

Currently some errors are parsed but mostly are handled as human-readable strings instead of using error codes.

Parsing errors are reported in the log of the calculation (accessible with the verdi process logshow command). Moreover, they are stored in the output_parameters output Dict node, under the key warnings, and are accessible with calc.res.warnings.

Here we report the warnings produced by the parser:

• Check in what units the inputs are given. If not $$\mathring{A}$$, the code prints out: Units not Ang, be sure this is OK!.

• Check the output verbosity. If different than 1, the parser cannot work as expected, and the code prints out: Parsing is only supported if output verbosity is set to 1.

• If the Wannierisation procedure stops after reaching the num_iter set in the input, the code prints out: Wannierisation finished because num_iter was reached.. This typically means that the convergence has not been reached.

• When the number of items in each line of _band.labelinfo.dat is not equal to 6, the code warns: Wrong number of items in line XXX of the labelinfo file - I will not assign that label

• When the second column (i.e. the index) of each line in _band.labelinfo.dat is not an integer, then the code warns: Invalid value for the index in line XXX of the labelinfo file, it's not an integer - I will not assign that label.

• If you use a Wannier90 version before v3.0, the file _band.labelinfo.dat is not generated. Thus, the old version of the parser (i.e. band_parser_legacy) will be used, but it needs to guess the exact position of the high-symmetry points. Therefore it will output the following warning: Note: no file named SEEDNAME_band.labelinfo.dat found. You are probably using a version of Wannier90 before 3.0. There, the labels associated with each k-points were not printed in output and there were also cases in which points were not calculated (see issue #195 on the Wannier90 GitHub page). I will anyway try to do my best to assign labels, but the assignment might be wrong (especially if there are path discontinuities).