9
1
mirror of https://github.com/QuantumPackage/qp2.git synced 2024-12-27 05:43:31 +01:00
qp2/docs/source/programmers_guide/new_ks.rst
Anthony Scemama 8b22e38c9c
Develop (#15)
* fixed laplacian of aos

* corrected the laplacians of aos

* added dft_one_e

* added new feature for new dft functionals

* changed the configure to add new functionals

* changed the configure

* added dft_one_e/README.rst

* added README.rst in new_functionals

* added source/programmers_guide/new_ks.rst

* Thesis Yann

* Added gmp installation in configure

* improved qp_e_conv_fci

* Doc

* Typos

* Added variance_max

* Fixed completion in qp_create

* modif TODO

* fixed DFT potential for n_states gt 1

* improved pot pbe

* trying to improve sr PBE

* fixed potential pbe

* fixed the vxc smashed for pbe sr and normal

* Comments in selection

* bug fixed by peter

* Fixed bug with zero beta electrons

* Update README.rst

* Update e_xc_new_func.irp.f

* Update links.rst

* Update quickstart.rst

* Update quickstart.rst

* updated cipsi

* Fixed energies of non-expected s2 (#9)

* Moved diag_algorithm in Davdison

* Add print_ci_vector in tools (#11)

* Fixed energies of non-expected s2

* Moved diag_algorithm in Davdison

* Fixed travis

* Added print_ci_vector

* Documentation

* Cleaned qp_set_mo_class.ml

* Removed Core in taskserver

* Merge develop-toto and manus (#12)

* Fixed energies of non-expected s2

* Moved diag_algorithm in Davdison

* Fixed travis

* Added print_ci_vector

* Documentation

* Cleaned qp_set_mo_class.ml

* Removed Core in taskserver

* Frozen core for heavy atoms

* Improved molden module

* In sync with manus

* Fixed some of the documentation errors

* Develop toto (#13)

* Fixed energies of non-expected s2

* Moved diag_algorithm in Davdison

* Fixed travis

* Added print_ci_vector

* Documentation

* Cleaned qp_set_mo_class.ml

* Removed Core in taskserver

* Frozen core for heavy atoms

* Improved molden module

* In sync with manus

* Fixed some of the documentation errors

* Develop manus (#14)

* modified printing for rpt2

* Comment

* Fixed plugins

* Scripting for functionals

* Documentation

* Develop (#10)

* fixed laplacian of aos

* corrected the laplacians of aos

* added dft_one_e

* added new feature for new dft functionals

* changed the configure to add new functionals

* changed the configure

* added dft_one_e/README.rst

* added README.rst in new_functionals

* added source/programmers_guide/new_ks.rst

* Thesis Yann

* Added gmp installation in configure

* improved qp_e_conv_fci

* Doc

* Typos

* Added variance_max

* Fixed completion in qp_create

* modif TODO

* fixed DFT potential for n_states gt 1

* improved pot pbe

* trying to improve sr PBE

* fixed potential pbe

* fixed the vxc smashed for pbe sr and normal

* Comments in selection

* bug fixed by peter

* Fixed bug with zero beta electrons

* Update README.rst

* Update e_xc_new_func.irp.f

* Update links.rst

* Update quickstart.rst

* Update quickstart.rst

* updated cipsi

* Fixed energies of non-expected s2 (#9)

* Moved diag_algorithm in Davdison

* some modifs

* modified gfortran_debug.cfg

* fixed automatization of functionals

* modified e_xc_general.irp.f

* minor modifs in ref_bitmask.irp.f

* modifying functionals

* rs_ks_scf and ks_scf compiles with the automatic handling of functionals

* removed prints

* fixed configure

* fixed the new functionals

* Merge toto

* modified automatic functionals

* Changed python into python2

* from_xyz suppressed

* Cleaning repo

* Update README.md

* Update README.md

* Contributors

* Update GITHUB.md

* bibtex
2019-03-07 16:29:06 +01:00

95 lines
4.8 KiB
ReStructuredText
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

============================================
Developping new functionals for KS or RS-DFT
============================================
The very basics
===============
To develop new functionals for |DFT| (or |RSDFT|) to be used in the SCF programs (:ref:`ks_scf` or :ref:`rs_ks_scf` ) or in multi-configurational |RSDFT| (see `<https://gitlab.com/eginer/qp_plugins_eginer>`_), you need to specify, at the end of the day, two things:
* *exchange/correlation* **energy functionals** used to compute the **energy**
* *exchange/correlation* **potentials** for (alpha/beta electrons) used to **optimize the wave function**
The providers to define such quantities, and then used by all the all the |DFT| programs, are (see :ref:`module_dft_one_e`):
* :c:data:`energy_x` and :c:data:`energy_c` : the *exchange* and *correlation* energy functionals (see :file:`e_xc_genera l.irp.f`)
* :c:data:`potential_x_alpha_ao` and :c:data:`potential_x_beta_ao` : the exchange potential for alpha/beta electrons on the |AO| basis (se e :file:`pot_general.irp.f`)
* :c:data:`potential_c_alpha_ao` and :c:data:`potential_c_beta_ao` : the correlation potential for alpha/beta electrons on the |AO| basis ( see :file:`pot_general.irp.f`)
From the |AO| basis, the providers for the exchange/correlation potentials of alpha/beta electrons on the |MO| basis are automatically obtained by a |AO| --> |MO| transformation.
So, at the end of the day, adding a new functional consists only in **setting a new value to these providers**.
The general philosphy
---------------------
The directory **functionals** contains only files ending with .irp.f whose name being the name of a specific functional.
All files in *a_functional*.irp.f **must** contain **at least** the following providers
* :c:data:`energy_x_a_functional` and :c:data:`energy_c_a_functional` which are of course the exchange and correlation energies
* :c:data:`potential_x_alpha_ao_a_functional` and :c:data:`potential_x_beta_ao_a_functional` which are the exchange alpha/beta potentials
* :c:data:`potential_c_alpha_ao_a_functional` and :c:data:`potential_c_beta_ao_a_functional` which are the correlation alpha/beta potentials
For instance, the file :file:`sr_lda.irp.f` contains the following providers
* :c:data:`energy_x_sr_lda` and :c:data:`energy_c_sr_lda` which are of course the exchange and correlation energies
* :c:data:`potential_x_alpha_ao_sr_lda` and :c:data:`potential_x_beta_ao_sr_lda` which are the exchange alpha/beta potentials
* :c:data:`potential_c_alpha_ao_sr_lda` and :c:data:`potential_c_beta_ao_sr_lda` which are the correlation alpha/beta potentials
Therefore, if you want to develop a new functional, just design a provider
To use a functional
Using the density for DFT calculations in the |QP|
==================================================
Different ways of defining the density for the DFT
--------------------------------------------------
There are many ways of defining a density, and the keyword to define it is :option:`density_for_dft density_for_dft`.
Here are the following options for that keyword:
* "KS" : density is obtained from **a single Slater determinant**
* "WFT" : density is obtained from **the wave function** which is stored in the |EZFIO| data base
* "input_density" : a one-body density matrix on the |MO| basis is read from the |EZFIO| data base, and the density is built from there (see :c:data:`data_one_e_dm_alpha_mo`)
* "damping_rs_dft" : damped density between "WFT" and "input_density" with the damping factor :option:`density_for_dft damping_for_rs_dft`.
.. note::
If an |MO| basis is already defined in the  |EZFIO| data base, the one-body density matrices will be defined
according to this |MO| basis. For instance, if "KS", the density constructed will be density of a single Slater
determinant built with the current |MO| basis stored in the |EZFIO| data base.
Once that you have defined how to define the density, you can easily access to the providers associated to it.
Value of the density and its gradients in real space
----------------------------------------------------
The density and its gradients evaluated on all grid points are (see :ref:`module_dft_utils_in_r`):
* :c:data:`one_e_dm_alpha_at_r` and :c:data:`one_e_dm_beta_at_r` : alpha/beta density at grid points
* :c:data:`one_e_dm_and_grad_alpha_in_r`, :c:data:`one_e_dm_and_grad_beta_in_r`: alpha/beta gradients (and densities)
If you want to evaluate the density and its gradients at a given point in space, please refer to:
* :c:func:`density_and_grad_alpha_beta_and_all_aos_and_grad_aos_at_r`
If you use these *providers* and subroutines, the density computed will be coherent with the choice of density that you specified
with :option:`density_for_dft density_for_dft`, and it will impact automatically the general providers of :ref:`module_dft_one_e`.