mirror of
https://github.com/triqs/dft_tools
synced 2024-12-22 04:13:47 +01:00
73 lines
3.7 KiB
ReStructuredText
73 lines
3.7 KiB
ReStructuredText
What you should know
|
|
====================
|
|
|
|
Probably, you can hardly wait to perform your first DFT+DMFT calculation
|
|
with the :program:`DFTTools` package. This documentation and user guide
|
|
should make it as easy as possible to get started quickly.
|
|
However, it is mutually important to sort out a few prerequisites first.
|
|
|
|
What is :program:`DFTTools`?
|
|
----------------------------
|
|
|
|
:program:`DFTTools` connects the :ref:`TRIQS <triqslibs:welcome>` library
|
|
to realistic materials calculations based
|
|
on density functional theory (DFT). It allows an efficient implementation
|
|
of DFT plus dynamical mean-field theory (DMFT) calculations and it supplies
|
|
tools and methods to construct Wannier functions and to perform the
|
|
DMFT self-consistency cycle in this basis set. Post-processing tools,
|
|
such as band-structure plotting or the calculation of transport properties
|
|
are also implemented. The package comes with a fully charge self-consistent
|
|
interface to the Wien2k band structure code, as well as a generic interface.
|
|
We assume that you are already know about DFT and the usage of Wien2k.
|
|
|
|
Have a look at :ref:`DFT+DMFT page <dftplusdmft>` for a brief introduction on
|
|
the DFT+DMFT method and on how the theory is reflected in the
|
|
:ref:`basic structure <structure>` of the :program:`DFTTools` package.
|
|
|
|
|
|
Understand the philosophy of :program:`DFTTools`
|
|
------------------------------------------------
|
|
|
|
The purpose of :program:`DFTTools` is to provide the necessary tools
|
|
required for a DFT+DMFT calculations. Putting those tools together to a working
|
|
DFT+DMFT implementation is the task of the user. We do not
|
|
supply an universal script which runs with the click of a button, simply because
|
|
each material requires a different treatment or different settings.
|
|
Building your own script offers a great deal of flexibility and customizability.
|
|
Additionally, the :ref:`DFTTools user guide <documentation>` is there to support you
|
|
during this process.
|
|
|
|
It should go without saying, but the verification of outputs and the inspection
|
|
of results on their meaningfulness is the responsibility of the user.
|
|
|
|
The :program:`DFTTools` package is a toolbox and **not** a black box!
|
|
|
|
|
|
Learn how to use :ref:`TRIQS <triqslibs:welcome>` (and the :ref:`CTHYB <triqscthyb:welcome>` solver)
|
|
----------------------------------------------------------------------------------------------------
|
|
|
|
As :program:`DFTTools` is a :ref:`TRIQS <triqslibs:welcome>` based application
|
|
it is beneficial to invest a few hours to become familiar with
|
|
the :ref:`TRIQS <triqslibs:welcome>` basics first. The
|
|
:ref:`TRIQS tutorial <triqslibs:tutorials>` covers
|
|
the most important aspects of :ref:`TRIQS <triqslibs:welcome>`. We recommend
|
|
downloading our hands-on training in the form of ipython notebooks from
|
|
the `tutorials repository on GitHub <https://github.com/TRIQS/tutorials>`_.
|
|
Tutorials 1 to 6 are on the :ref:`TRIQS <triqslibs:welcome>` library, whereas tutorials
|
|
7 and 8 are more specific to the usage of the :ref:`CTHYB <triqscthyb:welcome>`
|
|
hybridization-expansion solver. In general, those tutorials will take at least a full day to finish.
|
|
|
|
Afterwards you can continue with the :ref:`DFTTools user guide <documentation>`.
|
|
|
|
|
|
Maximum Entropy (MaxEnt)
|
|
------------------------
|
|
|
|
Analytic continuation is needed for many :ref:`post-processing tools <analysis>`, e.g. to
|
|
calculate the spectral function, the correlated band structure (:math:`A(k,\omega)`)
|
|
and to perform :ref:`transport calculations <Transport>`.
|
|
You can use the Pade approximation available in the :ref:`TRIQS <triqslibs:welcome>` library, however,
|
|
it turns out to be very unstable for noisy numerical data. Most of the time, the MaxEnt method
|
|
is used to obtain data on the real-frequency axis. At the moment neither :ref:`TRIQS <triqslibs:welcome>` nor
|
|
:program:`DFTTools` provide such routines.
|