.. _plovasp:

PLOVasp input file
==================

The general purpose of the PLOVasp tool is to transform
raw, non-normalized projectors generated by VASP into normalized
projectors corresponding to user-defined projected localized orbitals (PLO).
The PLOs can then be used for DFT+DMFT calculations with or without
charge self-consistency. PLOVasp also provides some utilities
for basic analysis of the generated projectors, such as outputting
density matrices, local Hamiltonians, and projected
density of states.

PLOs are determined by the energy window in which the raw projectors
are normalized. This allows to define either atomic-like strongly
localized Wannier functions (large energy window) or extended 
Wannier functions focusing on selected low-energy states (small
energy window).

In PLOVasp all projectors sharing the same energy window are combined
into a `projector group`. Technically, this allows one to define
several groups with different energy windows for the same set of
raw projectors. Note, however, that DFTtools does not support projector
groups at the moment but this feature might appear in future releases.

A set of projectors defined on sites realted to each other either by symmetry
or by sort along with a set of `l`, `m` quantum numbers forms a
`projector shell`. There could be several projectors shells in a
projector group, implying that they will be normalized within
the same energy window.

Projector shells and groups are specified by a user-defined input file
whose format is described below.

Input file format
-----------------

The input file is written in the standard config-file format.
Parameters (or 'options') are grouped into sections specified as
`[Section name]`. All parameters must be defined inside some section.

A PLOVasp input file can contain three types of sections:

#. **[General]**: includes parameters that are independent
   of a particular projector set, such as the Fermi level, additional 
   output (e.g. the density of states), etc.

#. **[Group <Ng>]**: describes projector groups, i.e. a set of
   projectors sharing the same energy window and normalization type.
   At the moment, DFTtools support only one projector group, therefore
   there should be no more than one projector group.

#. **[Shell <Ns>]**: contains parameters of a projector shell labelled
   with `<Ns>`. If there is only one group section and one shell section,
   the group section can be omitted and its required parameters can be
   given inside the single shell section.