quantum-espresso/LR_Modules/newdq.f90

169 lines
4.9 KiB
Fortran

!
! Copyright (C) 2001-2018 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 newdq (dvscf, npe)
!----------------------------------------------------------------------
!
! This routine computes the contribution of the selfconsistent
! change of the potential to the known part of the linear
! system and adds it to dvpsi.
!
!
USE kinds, ONLY : DP
USE ions_base, ONLY : nat, ityp, ntyp => nsp
USE cell_base, ONLY : tpiba
USE noncollin_module, ONLY : noncolin, nspin_mag
USE cell_base, ONLY : omega
USE fft_base, ONLY : dfftp
USE fft_interfaces, ONLY : fwfft
USE gvect, ONLY : g, gg, ngm, mill, eigts1, eigts2, eigts3
USE uspp, ONLY : okvan
USE uspp_param, ONLY : upf, lmaxq, nh, nhm
USE paw_variables, ONLY : okpaw
USE mp_bands, ONLY: intra_bgrp_comm
USE mp, ONLY: mp_sum
USE lrus, ONLY : int3, int3_paw
USE qpoint, ONLY : xq, eigqts
USE control_lr, ONLY : lgamma
implicit none
!
! The dummy variables
!
integer, intent(in) :: npe
! input: the number of perturbations
complex(DP), intent(in) :: dvscf (dfftp%nnr, nspin_mag, npe)
! input: the change of the selfconsistent pot.
!
! And the local variables
!
integer :: na, ig, nt, ir, ipert, is, ih, jh
! countera
real(DP), allocatable :: qmod (:), qg (:,:), ylmk0 (:,:)
! the modulus of q+G
! the values of q+G
! the spherical harmonics
complex(DP), external :: zdotc
! the scalar product function
complex(DP), allocatable :: aux1 (:), aux2 (:,:), veff (:), qgm(:)
! work space
if (.not.okvan) return
!
call start_clock ('newdq')
!
int3 (:,:,:,:,:) = (0.d0, 0.0d0)
allocate (aux1 (ngm))
allocate (aux2 (ngm , nspin_mag))
allocate (veff (dfftp%nnr))
allocate (ylmk0(ngm , lmaxq * lmaxq))
allocate (qgm (ngm))
allocate (qmod (ngm))
!
if (.not.lgamma) allocate (qg (3, ngm))
!
! first compute the spherical harmonics
!
if (.not.lgamma) then
call setqmod (ngm, xq, g, qmod, qg)
call ylmr2 (lmaxq * lmaxq, ngm, qg, qmod, ylmk0)
do ig = 1, ngm
qmod (ig) = sqrt (qmod (ig) ) * tpiba
enddo
else
call ylmr2 (lmaxq * lmaxq, ngm, g, gg, ylmk0)
do ig = 1, ngm
qmod (ig) = sqrt (gg (ig) ) * tpiba
enddo
endif
!
! and for each perturbation of this irreducible representation
! integrate the change of the self consistent potential and
! the Q functions
!
do ipert = 1, npe
do is = 1, nspin_mag
do ir = 1, dfftp%nnr
veff (ir) = dvscf (ir, is, ipert)
enddo
CALL fwfft ('Rho', veff, dfftp)
do ig = 1, ngm
aux2 (ig, is) = veff (dfftp%nl (ig) )
enddo
enddo
do nt = 1, ntyp
if (upf(nt)%tvanp ) then
do ih = 1, nh (nt)
do jh = ih, nh (nt)
call qvan2 (ngm, ih, jh, nt, qmod, qgm, ylmk0)
do na = 1, nat
if (ityp (na) == nt) then
do ig = 1, ngm
aux1(ig) = qgm(ig) * eigts1(mill(1,ig),na) * &
eigts2(mill(2,ig),na) * &
eigts3(mill(3,ig),na) * &
eigqts(na)
enddo
do is = 1, nspin_mag
int3(ih,jh,na,is,ipert) = omega * &
zdotc(ngm,aux1,1,aux2(1,is),1)
enddo
endif
enddo
enddo
enddo
do na = 1, nat
if (ityp(na) == nt) then
!
! We use the symmetry properties of the ps factor
!
do ih = 1, nh (nt)
do jh = ih, nh (nt)
do is = 1, nspin_mag
int3(jh,ih,na,is,ipert) = int3(ih,jh,na,is,ipert)
enddo
enddo
enddo
endif
enddo
endif
enddo
enddo
#if defined(__MPI)
call mp_sum ( int3, intra_bgrp_comm )
#endif
!
IF (noncolin) CALL set_int3_nc(npe)
!
! Sum of the USPP and PAW terms
! (see last two terms in Eq.(12) in PRB 81, 075123 (2010))
!
IF (okpaw) int3 = int3 + int3_paw
!
if (.not.lgamma) deallocate (qg)
deallocate (qmod)
deallocate (qgm)
deallocate (ylmk0)
deallocate (veff)
deallocate (aux2)
deallocate (aux1)
!
call stop_clock ('newdq')
!
return
!
end subroutine newdq