quantum-espresso/PHonon/PH/addnlcc.f90

131 lines
3.7 KiB
Fortran

!
! Copyright (C) 2001-2016 Quantum ESPRESSO group
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
subroutine addnlcc (imode0, drhoscf, npe)
!
! This routine adds a contribution to the dynamical matrix due
! to the NLCC
!
USE kinds, only : DP
USE ions_base, ONLY : nat
use funct, only : dft_is_gradient, dft_is_nonlocc
USE cell_base, ONLY : omega
use scf, only : rho, rho_core
USE gvect, ONLY : g, ngm
USE fft_base, ONLY : dfftp
USE noncollin_module, ONLY : nspin_lsda, nspin_gga, nspin_mag
USE dynmat, ONLY : dyn, dyn_rec
USE modes, ONLY : nirr, npert
USE uspp, ONLY : nlcc_any
USE mp_bands, ONLY: intra_bgrp_comm
USE mp, ONLY: mp_sum
USE qpoint, ONLY : xq
USE eqv, ONLY : dmuxc
USE gc_lr, ONLY: grho, dvxc_rr, dvxc_sr, dvxc_ss, dvxc_s
implicit none
integer :: imode0, npe
! input: the starting mode
! input: the number of perturbations
! input: the change of density due to perturbation
complex(DP) :: drhoscf (dfftp%nnr, nspin_mag, npe)
integer :: nrtot, ipert, jpert, is, is1, irr, ir, mode, mode1
! the total number of points
! counter on perturbations
! counter on spin
! counter on representations
! counter on real space points
! counter on modes
complex(DP) :: dyn1 (3 * nat, 3 * nat)
! auxiliary dynamical matrix
complex(DP), allocatable :: drhoc (:), dvaux (:,:)
! the change of the core
! the change of the potential
real(DP) :: fac
! auxiliary factor
if (.not.nlcc_any) return
allocate (drhoc( dfftp%nnr))
allocate (dvaux( dfftp%nnr, nspin_mag))
dyn1 (:,:) = (0.d0, 0.d0)
!
! compute the exchange and correlation potential for this mode
!
nrtot = dfftp%nr1 * dfftp%nr2 * dfftp%nr3
fac = 1.d0 / DBLE (nspin_lsda)
!
! add core charge to the density
!
rho%of_r(:,1) = rho%of_r(:,1) + rho_core(:)
!
! Compute the change of xc potential due to the perturbation
!
do ipert = 1, npe
mode = imode0 + ipert
dvaux (:,:) = (0.d0, 0.d0)
call addcore (mode, drhoc)
do is = 1, nspin_lsda
call daxpy (2 * dfftp%nnr, fac, drhoc, 1, drhoscf (1, is, ipert), 1)
enddo
do is = 1, nspin_lsda
do is1 = 1, nspin_mag
do ir = 1, dfftp%nnr
dvaux (ir, is) = dvaux (ir, is) + dmuxc (ir, is, is1) * &
drhoscf ( ir, is1, ipert)
enddo
enddo
enddo
!
! add gradient correction to xc, NB: if nlcc is true we need to add here
! its contribution. grho contains already the core charge
!
if ( dft_is_gradient() ) call dgradcorr (dfftp, rho%of_r, grho, dvxc_rr, &
dvxc_sr, dvxc_ss, dvxc_s, xq, drhoscf(1, 1, ipert), &
nspin_mag, nspin_gga, g, dvaux)
!
if (dft_is_nonlocc()) call dnonloccorr(rho%of_r, drhoscf(1,1,ipert), xq, dvaux)
!
do is = 1, nspin_lsda
call daxpy (2 * dfftp%nnr, - fac, drhoc, 1, drhoscf (1, is, ipert), 1)
enddo
mode1 = 0
do irr = 1, nirr
do jpert = 1, npert (irr)
mode1 = mode1 + 1
call addcore (mode1, drhoc)
do is = 1, nspin_lsda
dyn1 (mode, mode1) = dyn1 (mode, mode1) + &
dot_product (dvaux (:,is), drhoc) * &
omega * fac / DBLE (nrtot)
enddo
enddo
enddo
enddo
!
rho%of_r(:,1) = rho%of_r(:,1) - rho_core(:)
!
! collect contributions from all r/G points.
!
call mp_sum ( dyn1, intra_bgrp_comm )
dyn (:,:) = dyn(:,:) + dyn1(:,:)
dyn_rec(:,:)=dyn_rec(:,:)+dyn1(:,:)
deallocate (dvaux)
deallocate (drhoc)
return
end subroutine addnlcc