quantum-espresso/VdW/incdrhoscf.f90

89 lines
2.6 KiB
Fortran

!
! Copyright (C) 2001 PWSCF 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 incdrhoscf_vdw (drhoscf, weight, ik, mode)
!-----------------------------------------------------------------------
!
! This routine computes the change of the charge density due to the
! perturbation. It is called at the end of the computation of the
! change of the wavefunction for a given k point.
!
!
#include "f_defs.h"
USE kinds, ONLY : DP
USE ions_base, ONLY : nat
! USE wavefunctions_module, ONLY: evc
USE uspp_param, ONLY : nhm
USE eff_v, ONLY : evc => evc_veff
use pwcom
use phcom
implicit none
integer :: ik
! input: the k point
real(kind=DP) :: weight
! input: the weight of the k point
complex(kind=DP) :: drhoscf (nrxxs) , dbecsum (nhm*(nhm+1)/2,nat)
! output: the change of the charge densit
! inp/out: the accumulated dbec
integer :: mode
!
! here the local variable
!
real(kind=DP) :: wgt
! the effective weight of the k point
complex(kind=DP), allocatable :: psi (:), dpsic (:)
! the wavefunctions in real space
! the change of wavefunctions in real space
integer :: ibnd, jbnd, ikk, ir, ig
! counters
call start_clock ('incdrhoscf')
allocate (dpsic( nrxxs))
allocate (psi ( nrxxs))
wgt = 2.d0 * weight / omega
if (lgamma) then
ikk = ik
else
ikk = 2 * ik - 1
endif
!
! dpsi contains the perturbed wavefunctions of this k point
! evc contains the unperturbed wavefunctions of this k point
!
do ibnd = 1, nbnd_occ (ikk)
psi (:) = (0.d0, 0.d0)
do ig = 1, npw
psi (nls (igk (ig) ) ) = evc (ig, ibnd)
enddo
call cft3s (psi, nr1s, nr2s, nr3s, nrx1s, nrx2s, nrx3s, + 2)
dpsic(:) = (0.d0, 0.d0)
do ig = 1, npwq
dpsic (nls (igkq (ig) ) ) = dpsi (ig, ibnd)
enddo
call cft3s (dpsic, nr1s, nr2s, nr3s, nrx1s, nrx2s, nrx3s, + 2)
do ir = 1, nrxxs
! drhoscf (ir) = drhoscf (ir) + wgt * CONJG (psi (ir) ) * dpsic (ir)
drhoscf (ir) = drhoscf (ir) + wgt * REAL( CONJG(psi(ir)) * dpsic (ir) )
enddo
enddo
!print*,'drhoscf=', sum(abs(REAL(drhoscf))), SUM(ABS(AIMAG(drhoscf)))
! call addusdbec (ik, wgt, dpsi, dbecsum)
deallocate (psi)
deallocate (dpsic)
call stop_clock ('incdrhoscf')
return
end subroutine incdrhoscf_vdw