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qp2/doc/_sources/modules/becke_numerical_grid.rst.txt
Anthony Scemama b7c7fd7e6f Introduced doc
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.. _module_becke_numerical_grid:
.. program:: becke_numerical_grid
.. default-role:: option
====================
becke_numerical_grid
====================
This module contains all quantities needed to build Becke's grid used in general for DFT integration. Note that it can be used for whatever integration in R^3 as long as the functions to be integrated are mostly concentrated near the atomic regions.
This grid is built as the reunion of a spherical grid around each atom. Each spherical grid contains
a certain number of radial and angular points. No pruning is done on the angular part of the grid.
The main keyword for that module is:
* :option:`becke_numerical_grid grid_type_sgn` which controls the precision of the grid according the standard **SG-n** grids. This keyword controls the two providers `n_points_integration_angular` `n_points_radial_grid`.
The main providers of that module are:
* `n_points_integration_angular` which is the number of angular integration points. WARNING: it obeys to specific rules so it cannot be any integer number. Some of the possible values are [ 50 | 74 | 170 | 194 | 266 | 302 | 590 | 1202 | 2030 | 5810 ] for instance. See :file:`angular.f` for more details.
* `n_points_radial_grid` which is the number of radial angular points. This can be any strictly positive integer. Nevertheless, a minimum of 50 is in general necessary.
* `final_grid_points` which are the (x,y,z) coordinates of the grid points.
* `final_weight_at_r_vector` which are the weights at each grid point
For a simple example of how to use the grid, see :file:`example.irp.f`.
The spherical integration uses Lebedev-Laikov grids, which was used from the code distributed through CCL (http://www.ccl.net/).
See next section for explanations and citation policies.
.. code-block:: text
This subroutine is part of a set of subroutines that generate
Lebedev grids [1-6] for integration on a sphere. The original
C-code [1] was kindly provided by Dr. Dmitri N. Laikov and
translated into fortran by Dr. Christoph van Wuellen.
This subroutine was translated using a C to fortran77 conversion
tool written by Dr. Christoph van Wuellen.
Users of this code are asked to include reference [1] in their
publications, and in the user- and programmers-manuals
describing their codes.
This code was distributed through CCL (http://www.ccl.net/).
[1] V.I. Lebedev, and D.N. Laikov
"A quadrature formula for the sphere of the 131st
algebraic order of accuracy"
Doklady Mathematics, Vol. 59, No. 3, 1999, pp. 477-481.
[2] V.I. Lebedev
"A quadrature formula for the sphere of 59th algebraic
order of accuracy"
Russian Acad. Sci. Dokl. Math., Vol. 50, 1995, pp. 283-286.
[3] V.I. Lebedev, and A.L. Skorokhodov
"Quadrature formulas of orders 41, 47, and 53 for the sphere"
Russian Acad. Sci. Dokl. Math., Vol. 45, 1992, pp. 587-592.
[4] V.I. Lebedev
"Spherical quadrature formulas exact to orders 25-29"
Siberian Mathematical Journal, Vol. 18, 1977, pp. 99-107.
[5] V.I. Lebedev
"Quadratures on a sphere"
Computational Mathematics and Mathematical Physics, Vol. 16,
1976, pp. 10-24.
[6] V.I. Lebedev
"Values of the nodes and weights of ninth to seventeenth
order Gauss-Markov quadrature formulae invariant under the
octahedron group with inversion"
Computational Mathematics and Mathematical Physics, Vol. 15,
1975, pp. 44-51.
EZFIO parameters
----------------
.. option:: grid_type_sgn
Type of grid used for the Becke's numerical grid. Can be, by increasing accuracy: [ 0 | 1 | 2 | 3 ]
Default: 2
Providers
---------
.. c:var:: alpha_knowles
File : :file:`becke_numerical_grid/integration_radial.irp.f`
.. code:: fortran
double precision, allocatable :: alpha_knowles (100)
Recommended values for the alpha parameters according to the paper of Knowles (JCP, 104, 1996)
as a function of the nuclear charge
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
.. c:var:: angular_quadrature_points
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
double precision, allocatable :: angular_quadrature_points (n_points_integration_angular,3)
double precision, allocatable :: weights_angular_points (n_points_integration_angular)
weights and grid points for the integration on the angular variables on
the unit sphere centered on (0,0,0)
According to the LEBEDEV scheme
Needs:
.. hlist::
:columns: 3
* :c:data:`n_points_radial_grid`
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
.. c:var:: dr_radial_integral
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
double precision, allocatable :: grid_points_radial (n_points_radial_grid)
double precision :: dr_radial_integral
points in [0,1] to map the radial integral [0,\infty]
Needs:
.. hlist::
:columns: 3
* :c:data:`n_points_radial_grid`
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
.. c:var:: final_grid_points
File : :file:`becke_numerical_grid/grid_becke_vector.irp.f`
.. code:: fortran
double precision, allocatable :: final_grid_points (3,n_points_final_grid)
double precision, allocatable :: final_weight_at_r_vector (n_points_final_grid)
integer, allocatable :: index_final_points (3,n_points_final_grid)
integer, allocatable :: index_final_points_reverse (n_points_integration_angular,n_points_radial_grid,nucl_num)
final_grid_points(1:3,j) = (/ x, y, z /) of the jth grid point
final_weight_at_r_vector(i) = Total weight function of the ith grid point which contains the Lebedev, Voronoi and radial weights contributions
index_final_points(1:3,i) = gives the angular, radial and atomic indices associated to the ith grid point
index_final_points_reverse(i,j,k) = index of the grid point having i as angular, j as radial and l as atomic indices
Needs:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
* :c:data:`n_points_final_grid`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_num`
Needed by:
.. hlist::
:columns: 3
* :c:data:`aos_grad_in_r_array`
* :c:data:`aos_in_r_array`
* :c:data:`aos_lapl_in_r_array`
* :c:data:`aos_sr_vc_alpha_lda_w`
* :c:data:`aos_sr_vc_alpha_pbe_w`
* :c:data:`aos_vc_alpha_lda_w`
* :c:data:`aos_vc_alpha_pbe_w`
* :c:data:`energy_sr_x_lda`
* :c:data:`energy_sr_x_pbe`
* :c:data:`energy_x_lda`
* :c:data:`energy_x_pbe`
* :c:data:`mos_in_r_array`
* :c:data:`one_e_dm_alpha_at_r`
* :c:data:`one_e_dm_and_grad_alpha_in_r`
.. c:var:: final_weight_at_r
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
double precision, allocatable :: final_weight_at_r (n_points_integration_angular,n_points_radial_grid,nucl_num)
Total weight on each grid point which takes into account all Lebedev, Voronoi and radial weights.
Needs:
.. hlist::
:columns: 3
* :c:data:`alpha_knowles`
* :c:data:`angular_quadrature_points`
* :c:data:`grid_points_radial`
* :c:data:`m_knowles`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_charge`
* :c:data:`nucl_num`
* :c:data:`weight_at_r`
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_grid_points`
* :c:data:`n_points_final_grid`
.. c:var:: final_weight_at_r_vector
File : :file:`becke_numerical_grid/grid_becke_vector.irp.f`
.. code:: fortran
double precision, allocatable :: final_grid_points (3,n_points_final_grid)
double precision, allocatable :: final_weight_at_r_vector (n_points_final_grid)
integer, allocatable :: index_final_points (3,n_points_final_grid)
integer, allocatable :: index_final_points_reverse (n_points_integration_angular,n_points_radial_grid,nucl_num)
final_grid_points(1:3,j) = (/ x, y, z /) of the jth grid point
final_weight_at_r_vector(i) = Total weight function of the ith grid point which contains the Lebedev, Voronoi and radial weights contributions
index_final_points(1:3,i) = gives the angular, radial and atomic indices associated to the ith grid point
index_final_points_reverse(i,j,k) = index of the grid point having i as angular, j as radial and l as atomic indices
Needs:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
* :c:data:`n_points_final_grid`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_num`
Needed by:
.. hlist::
:columns: 3
* :c:data:`aos_grad_in_r_array`
* :c:data:`aos_in_r_array`
* :c:data:`aos_lapl_in_r_array`
* :c:data:`aos_sr_vc_alpha_lda_w`
* :c:data:`aos_sr_vc_alpha_pbe_w`
* :c:data:`aos_vc_alpha_lda_w`
* :c:data:`aos_vc_alpha_pbe_w`
* :c:data:`energy_sr_x_lda`
* :c:data:`energy_sr_x_pbe`
* :c:data:`energy_x_lda`
* :c:data:`energy_x_pbe`
* :c:data:`mos_in_r_array`
* :c:data:`one_e_dm_alpha_at_r`
* :c:data:`one_e_dm_and_grad_alpha_in_r`
.. c:var:: grid_points_per_atom
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
double precision, allocatable :: grid_points_per_atom (3,n_points_integration_angular,n_points_radial_grid,nucl_num)
x,y,z coordinates of grid points used for integration in 3d space
Needs:
.. hlist::
:columns: 3
* :c:data:`alpha_knowles`
* :c:data:`angular_quadrature_points`
* :c:data:`grid_points_radial`
* :c:data:`m_knowles`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_charge`
* :c:data:`nucl_coord`
* :c:data:`nucl_num`
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_grid_points`
* :c:data:`one_e_dm_alpha_in_r`
* :c:data:`weight_at_r`
.. c:var:: grid_points_radial
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
double precision, allocatable :: grid_points_radial (n_points_radial_grid)
double precision :: dr_radial_integral
points in [0,1] to map the radial integral [0,\infty]
Needs:
.. hlist::
:columns: 3
* :c:data:`n_points_radial_grid`
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
.. c:var:: index_final_points
File : :file:`becke_numerical_grid/grid_becke_vector.irp.f`
.. code:: fortran
double precision, allocatable :: final_grid_points (3,n_points_final_grid)
double precision, allocatable :: final_weight_at_r_vector (n_points_final_grid)
integer, allocatable :: index_final_points (3,n_points_final_grid)
integer, allocatable :: index_final_points_reverse (n_points_integration_angular,n_points_radial_grid,nucl_num)
final_grid_points(1:3,j) = (/ x, y, z /) of the jth grid point
final_weight_at_r_vector(i) = Total weight function of the ith grid point which contains the Lebedev, Voronoi and radial weights contributions
index_final_points(1:3,i) = gives the angular, radial and atomic indices associated to the ith grid point
index_final_points_reverse(i,j,k) = index of the grid point having i as angular, j as radial and l as atomic indices
Needs:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
* :c:data:`n_points_final_grid`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_num`
Needed by:
.. hlist::
:columns: 3
* :c:data:`aos_grad_in_r_array`
* :c:data:`aos_in_r_array`
* :c:data:`aos_lapl_in_r_array`
* :c:data:`aos_sr_vc_alpha_lda_w`
* :c:data:`aos_sr_vc_alpha_pbe_w`
* :c:data:`aos_vc_alpha_lda_w`
* :c:data:`aos_vc_alpha_pbe_w`
* :c:data:`energy_sr_x_lda`
* :c:data:`energy_sr_x_pbe`
* :c:data:`energy_x_lda`
* :c:data:`energy_x_pbe`
* :c:data:`mos_in_r_array`
* :c:data:`one_e_dm_alpha_at_r`
* :c:data:`one_e_dm_and_grad_alpha_in_r`
.. c:var:: index_final_points_reverse
File : :file:`becke_numerical_grid/grid_becke_vector.irp.f`
.. code:: fortran
double precision, allocatable :: final_grid_points (3,n_points_final_grid)
double precision, allocatable :: final_weight_at_r_vector (n_points_final_grid)
integer, allocatable :: index_final_points (3,n_points_final_grid)
integer, allocatable :: index_final_points_reverse (n_points_integration_angular,n_points_radial_grid,nucl_num)
final_grid_points(1:3,j) = (/ x, y, z /) of the jth grid point
final_weight_at_r_vector(i) = Total weight function of the ith grid point which contains the Lebedev, Voronoi and radial weights contributions
index_final_points(1:3,i) = gives the angular, radial and atomic indices associated to the ith grid point
index_final_points_reverse(i,j,k) = index of the grid point having i as angular, j as radial and l as atomic indices
Needs:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
* :c:data:`n_points_final_grid`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_num`
Needed by:
.. hlist::
:columns: 3
* :c:data:`aos_grad_in_r_array`
* :c:data:`aos_in_r_array`
* :c:data:`aos_lapl_in_r_array`
* :c:data:`aos_sr_vc_alpha_lda_w`
* :c:data:`aos_sr_vc_alpha_pbe_w`
* :c:data:`aos_vc_alpha_lda_w`
* :c:data:`aos_vc_alpha_pbe_w`
* :c:data:`energy_sr_x_lda`
* :c:data:`energy_sr_x_pbe`
* :c:data:`energy_x_lda`
* :c:data:`energy_x_pbe`
* :c:data:`mos_in_r_array`
* :c:data:`one_e_dm_alpha_at_r`
* :c:data:`one_e_dm_and_grad_alpha_in_r`
.. c:var:: m_knowles
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
integer :: m_knowles
value of the "m" parameter in the equation (7) of the paper of Knowles (JCP, 104, 1996)
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
.. c:var:: n_points_final_grid
File : :file:`becke_numerical_grid/grid_becke_vector.irp.f`
.. code:: fortran
integer :: n_points_final_grid
Number of points which are non zero
Needs:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_num`
Needed by:
.. hlist::
:columns: 3
* :c:data:`aos_grad_in_r_array`
* :c:data:`aos_in_r_array`
* :c:data:`aos_lapl_in_r_array`
* :c:data:`aos_sr_vc_alpha_lda_w`
* :c:data:`aos_sr_vc_alpha_pbe_w`
* :c:data:`aos_vc_alpha_lda_w`
* :c:data:`aos_vc_alpha_pbe_w`
* :c:data:`energy_sr_x_lda`
* :c:data:`energy_sr_x_pbe`
* :c:data:`energy_x_lda`
* :c:data:`energy_x_pbe`
* :c:data:`final_grid_points`
* :c:data:`mos_grad_in_r_array`
* :c:data:`mos_in_r_array`
* :c:data:`mos_lapl_in_r_array`
* :c:data:`one_e_dm_alpha_at_r`
* :c:data:`one_e_dm_and_grad_alpha_in_r`
* :c:data:`potential_sr_c_alpha_ao_lda`
* :c:data:`potential_sr_x_alpha_ao_lda`
* :c:data:`potential_sr_x_alpha_ao_pbe`
* :c:data:`potential_x_alpha_ao_lda`
* :c:data:`potential_x_alpha_ao_pbe`
.. c:var:: n_points_grid_per_atom
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
integer :: n_points_grid_per_atom
Number of grid points per atom
Needs:
.. hlist::
:columns: 3
* :c:data:`n_points_radial_grid`
.. c:var:: n_points_integration_angular
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
integer :: n_points_radial_grid
integer :: n_points_integration_angular
n_points_radial_grid = number of radial grid points per atom
n_points_integration_angular = number of angular grid points per atom
These numbers are automatically set by setting the grid_type_sgn parameter
Needs:
.. hlist::
:columns: 3
* :c:data:`grid_type_sgn`
Needed by:
.. hlist::
:columns: 3
* :c:data:`angular_quadrature_points`
* :c:data:`final_grid_points`
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
* :c:data:`grid_points_radial`
* :c:data:`n_points_final_grid`
* :c:data:`n_points_grid_per_atom`
* :c:data:`one_e_dm_alpha_in_r`
* :c:data:`weight_at_r`
.. c:var:: n_points_radial_grid
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
integer :: n_points_radial_grid
integer :: n_points_integration_angular
n_points_radial_grid = number of radial grid points per atom
n_points_integration_angular = number of angular grid points per atom
These numbers are automatically set by setting the grid_type_sgn parameter
Needs:
.. hlist::
:columns: 3
* :c:data:`grid_type_sgn`
Needed by:
.. hlist::
:columns: 3
* :c:data:`angular_quadrature_points`
* :c:data:`final_grid_points`
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
* :c:data:`grid_points_radial`
* :c:data:`n_points_final_grid`
* :c:data:`n_points_grid_per_atom`
* :c:data:`one_e_dm_alpha_in_r`
* :c:data:`weight_at_r`
.. c:var:: weight_at_r
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
double precision, allocatable :: weight_at_r (n_points_integration_angular,n_points_radial_grid,nucl_num)
Weight function at grid points : w_n(r) according to the equation (22)
of Becke original paper (JCP, 88, 1988)
The "n" discrete variable represents the nucleis which in this array is
represented by the last dimension and the points are labelled by the
other dimensions.
Needs:
.. hlist::
:columns: 3
* :c:data:`grid_points_per_atom`
* :c:data:`n_points_radial_grid`
* :c:data:`nucl_coord_transp`
* :c:data:`nucl_dist_inv`
* :c:data:`nucl_num`
* :c:data:`slater_bragg_type_inter_distance_ua`
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
.. c:var:: weights_angular_points
File : :file:`becke_numerical_grid/grid_becke.irp.f`
.. code:: fortran
double precision, allocatable :: angular_quadrature_points (n_points_integration_angular,3)
double precision, allocatable :: weights_angular_points (n_points_integration_angular)
weights and grid points for the integration on the angular variables on
the unit sphere centered on (0,0,0)
According to the LEBEDEV scheme
Needs:
.. hlist::
:columns: 3
* :c:data:`n_points_radial_grid`
Needed by:
.. hlist::
:columns: 3
* :c:data:`final_weight_at_r`
* :c:data:`grid_points_per_atom`
Subroutines / functions
-----------------------
.. c:function:: cell_function_becke:
File : :file:`becke_numerical_grid/step_function_becke.irp.f`
.. code:: fortran
double precision function cell_function_becke(r,atom_number)
atom_number :: atom on which the cell function of Becke (1988, JCP,88(4))
r(1:3) :: x,y,z coordinantes of the current point
Needs:
.. hlist::
:columns: 3
* :c:data:`nucl_dist_inv`
* :c:data:`slater_bragg_type_inter_distance_ua`
* :c:data:`nucl_coord_transp`
* :c:data:`nucl_num`
.. c:function:: derivative_knowles_function:
File : :file:`becke_numerical_grid/integration_radial.irp.f`
.. code:: fortran
double precision function derivative_knowles_function(alpha,m,x)
Derivative of the function proposed by Knowles (JCP, 104, 1996) for distributing the radial points
.. c:function:: example_becke_numerical_grid:
File : :file:`becke_numerical_grid/example.irp.f`
.. code:: fortran
subroutine example_becke_numerical_grid
subroutine that illustrates the main features available in becke_numerical_grid
Needs:
.. hlist::
:columns: 3
* :c:data:`n_points_final_grid`
* :c:data:`final_weight_at_r`
* :c:data:`n_points_radial_grid`
* :c:data:`grid_points_per_atom`
* :c:data:`final_grid_points`
* :c:data:`nucl_coord`
* :c:data:`nucl_num`
.. c:function:: f_function_becke:
File : :file:`becke_numerical_grid/step_function_becke.irp.f`
.. code:: fortran
double precision function f_function_becke(x)
.. c:function:: knowles_function:
File : :file:`becke_numerical_grid/integration_radial.irp.f`
.. code:: fortran
double precision function knowles_function(alpha,m,x)
Function proposed by Knowles (JCP, 104, 1996) for distributing the radial points :
the Log "m" function ( equation (7) in the paper )
.. c:function:: step_function_becke:
File : :file:`becke_numerical_grid/step_function_becke.irp.f`
.. code:: fortran
double precision function step_function_becke(x)
Step function of the Becke paper (1988, JCP,88(4))
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