quantum-espresso/PW/addusdens.f90

144 lines
3.9 KiB
Fortran

!
! Copyright (C) 2001-2006 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 addusdens(rho)
!----------------------------------------------------------------------
!
USE realus, ONLY : addusdens_r
USE control_flags, ONLY : tqr
USE noncollin_module, ONLY : nspin_mag
USE grid_dimensions, ONLY : nrxx
USE kinds, ONLY : DP
!
IMPLICIT NONE
!
!
REAL(kind=dp), intent(inout) :: rho(nrxx,nspin_mag)
!
IF ( tqr ) THEN
CALL addusdens_r(rho,.true.)
ELSE
CALL addusdens_g(rho)
END IF
!
RETURN
!
END SUBROUTINE addusdens
!
!----------------------------------------------------------------------
subroutine addusdens_g(rho)
!----------------------------------------------------------------------
!
! This routine adds to the charge density the part which is due to
! the US augmentation.
!
USE kinds, ONLY : DP
USE ions_base, ONLY : nat, ntyp => nsp, ityp
USE fft_base, ONLY : dfftp
USE fft_interfaces, ONLY : invfft
USE gvect, ONLY : ngm, nl, nlm, gg, g, &
eigts1, eigts2, eigts3, mill
USE noncollin_module, ONLY : noncolin, nspin_mag
USE uspp, ONLY : becsum, okvan
USE uspp_param, ONLY : upf, lmaxq, nh
USE control_flags, ONLY : gamma_only
USE wavefunctions_module, ONLY : psic
!
implicit none
!
REAL(kind=dp), intent(inout) :: rho(dfftp%nnr,nspin_mag)
!
! here the local variables
!
integer :: ig, na, nt, ih, jh, ijh, is
! counters
real(DP), allocatable :: qmod (:), ylmk0 (:,:)
! the modulus of G
! the spherical harmonics
complex(DP) :: skk
complex(DP), allocatable :: aux (:,:), qgm(:)
! work space for rho(G,nspin)
! Fourier transform of q
if (.not.okvan) return
call start_clock ('addusdens')
allocate (aux ( ngm, nspin_mag))
allocate (qmod( ngm))
allocate (qgm( ngm))
allocate (ylmk0( ngm, lmaxq * lmaxq))
aux (:,:) = (0.d0, 0.d0)
call ylmr2 (lmaxq * lmaxq, ngm, g, gg, ylmk0)
do ig = 1, ngm
qmod (ig) = sqrt (gg (ig) )
enddo
do nt = 1, ntyp
if ( upf(nt)%tvanp ) then
ijh = 0
do ih = 1, nh (nt)
do jh = ih, nh (nt)
#ifdef DEBUG_ADDUSDENS
call start_clock ('addus:qvan2')
#endif
call qvan2 (ngm, ih, jh, nt, qmod, qgm, ylmk0)
#ifdef DEBUG_ADDUSDENS
call stop_clock ('addus:qvan2')
#endif
ijh = ijh + 1
do na = 1, nat
if (ityp (na) .eq.nt) then
!
! Multiply becsum and qg with the correct structure factor
!
#ifdef DEBUG_ADDUSDENS
call start_clock ('addus:aux')
#endif
do is = 1, nspin_mag
do ig = 1, ngm
skk = eigts1 (mill (1,ig), na) * &
eigts2 (mill (2,ig), na) * &
eigts3 (mill (3,ig), na)
aux(ig,is)=aux(ig,is) + qgm(ig)*skk*becsum(ijh,na,is)
enddo
enddo
#ifdef DEBUG_ADDUSDENS
call stop_clock ('addus:aux')
#endif
endif
enddo
enddo
enddo
endif
enddo
!
deallocate (ylmk0)
deallocate (qgm)
deallocate (qmod)
!
! convert aux to real space and add to the charge density
!
do is = 1, nspin_mag
psic(:) = (0.d0, 0.d0)
psic( nl(:) ) = aux(:,is)
if (gamma_only) psic( nlm(:) ) = CONJG(aux(:,is))
CALL invfft ('Dense', psic, dfftp)
rho(:, is) = rho(:, is) + DBLE (psic (:) )
enddo
deallocate (aux)
call stop_clock ('addusdens')
return
end subroutine addusdens_g