mirror of
https://github.com/triqs/dft_tools
synced 2024-07-02 01:16:09 +02:00
4c920b8312
The documentation has been slightly rewritten and extended to follow the recent changes. The modifications include: - ProjectorSet class is now replaced by ProjectorShell - the workflow has been refined - the electronic structure part is represented by class ElectronicStructure
141 lines
4.6 KiB
ReStructuredText
141 lines
4.6 KiB
ReStructuredText
.. highlight:: python
|
|
|
|
#########
|
|
PLO tools
|
|
#########
|
|
|
|
Introduction
|
|
************
|
|
|
|
This set of tools is intended for processing of raw projectors read
|
|
from VASP. One of the main tasks is to generate an orthonormalized subset
|
|
of PLOs constructed according to the :doc:`config-file </config>`.
|
|
|
|
To produce the final output the following steps are undertaken:
|
|
|
|
* Parse input config-file
|
|
|
|
* Input raw VASP data
|
|
|
|
* Convert the raw VASP data into an internal representaion and check it for consistency.
|
|
|
|
* Generate a set of projector shells according to the parameters of the config-file
|
|
|
|
* Create a set of projector groups
|
|
|
|
* Perform necessary group operations (such as :ref:`orthogonalization<ortho>`) on the constituing shells
|
|
|
|
* Calculate and output some useful quantities (bare density matrix, DOS, etc.)
|
|
|
|
|
|
Initial Processing
|
|
******************
|
|
|
|
The raw data from VASP files is initially read in simple objects (containers).
|
|
Then these objects are combined in an another object containing all necessary
|
|
electronic structure data. At this stage simple consistency checks are performed:
|
|
|
|
* the basic dimensions, such as the number of bands, number of `k`-points, etc.,
|
|
are consistent for all data
|
|
|
|
* the `k`-point mesh are read both the IBZKPT and EIGENVAL and it is worth checking
|
|
that both sets are coinciding
|
|
|
|
* in case tetrahedron data is read from IBZKPT, the tetrahedron volume must be related
|
|
to the total volume of the unit cell as derived from POSCAR
|
|
|
|
All electronic structure from VASP is stored in a class ElectronicStructure:
|
|
|
|
.. autoclass:: elstruct.ElectronicStructure
|
|
:members:
|
|
|
|
|
|
Consistency with parameters
|
|
|
|
* parameters in the config-file should pass trivial checks such as that the ion
|
|
list does not contain non-existing ions (boundary check for ion indices)
|
|
|
|
.. function:: check_vasp_data_consistency(conf_pars, vasp_data)
|
|
|
|
**Parameters**:
|
|
|
|
- *conf_pars* (dict) : dictionary of input parameters from conf-file
|
|
- *vasp_data* (dict) : dictionary containing all VASP data
|
|
|
|
**Returns**:
|
|
|
|
*None*
|
|
|
|
**Raises**:
|
|
|
|
A meaningful exception indicating an inconsistency in the input data
|
|
|
|
|
|
Selecting projector subsets
|
|
---------------------------
|
|
|
|
The first step of PLO processing is to select subsets of projectors
|
|
corresponding to PLO groups. Each group contains a set of shells.
|
|
Each projector shell is represented by an object 'ProjectorShell'
|
|
that contains an array of projectors and information on the shell itself
|
|
(orbital number, ions, etc.). 'ProjectorShell's are contained in
|
|
both a list of shells (according to the original list as read
|
|
from config-file) and in a 'ProjectorGroup' object, the latter
|
|
also providing information about the energy window.
|
|
`[In fact, shell container can be a simple dictionary.]`
|
|
|
|
Order of operations:
|
|
|
|
- transform projectors (all bands) in each shell
|
|
- select transformed shell projectors for a given group within the window
|
|
- orthogonalize if necessary projectors within a group by performing
|
|
the following operations for each k-point:
|
|
* combine all projector shells into a single array
|
|
* orthogonalize the array
|
|
* distribute back the arrays assuming that the order is preserved
|
|
|
|
|
|
.. autoclass:: plotools.ProjectorShell
|
|
:members:
|
|
|
|
|
|
The class is using a helper function `select_bands()` for selecting a subset of bands.
|
|
|
|
.. function:: select_bands(eigvals, emin, emax)
|
|
|
|
**Parameters**:
|
|
|
|
- *eigvals* (numpy.array) : array of eigenvalues
|
|
- *emin*, *emax* (float) : energy window
|
|
|
|
**Returns**:
|
|
|
|
*ib_win*, *nb_min*, *nb_max* (numpy.array[int], int, int) :
|
|
lowest and highest indices of the selected bands
|
|
|
|
|
|
.. _ortho:
|
|
|
|
Orthogonalization
|
|
=================
|
|
|
|
At the second stage the selected projectors are orthogonalized (orthonormalized).
|
|
Orthogonalization can be performed in different ways if projection is made
|
|
on several ions or if several correlated shells per ion are considered.
|
|
In the case of several correlated ions per unit cell (and one correlated shell per ion)
|
|
at least two options can be considered:
|
|
|
|
#. Projectors are normalized for each ion separetely. In this case, corresponding
|
|
Wannier functions for different ions are generally not orthogonal.
|
|
|
|
#. Projectors are normalized for all ions in the unit cell simultaneously. This
|
|
ensures that the Wannier functions for different ions are mutually orthogonal.
|
|
|
|
The way the normalization of a PLO group is done is controlled by two group parameters:
|
|
|
|
- *NORMALIZE* (True/False) : indicates whether the PLO group is normalized (True by default)
|
|
- *NORMION* (True/False) : indicates whether the PLO group is normalized on a per-ion basis
|
|
(False by default)
|
|
|
|
|