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quantum-espresso/GWW/pw4gww/dft_exchange.f90

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!
! Copyright (C) 2001-2013 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 dft_exchange(nbnd_v,nbnd_s,n_set, e_x,ks_wfcs)
!this subroutine calculates the exchange
!energy term for every state and writes on disk
USE io_global, ONLY : stdout, ionode, ionode_id
USE io_files, ONLY : prefix, tmp_dir, iunwfc, nwordwfc
USE mp_global, ONLY : nproc_pool, me_pool
USE kinds, ONLY : DP
USE basis
USE klist
USE constants, ONLY : e2, pi, tpi, fpi, RYTOEV
USE wvfct, ONLY : npwx, npw, nbnd, wg
USE gvecw, ONLY : gcutw
USE cell_base, ONLY: at, alat, tpiba, omega, tpiba2,bg
USE wannier_gw
USE gvect
USE gvecs, ONLY : nls, nlsm, doublegrid
USE uspp
USE uspp_param, ONLY : lmaxq,upf,nh, nhm
USE wavefunctions_module, ONLY : psic
! USE realus, ONLY : adduspos_gamma_r
USE cell_base, ONLY : at, bg, omega
USE mp, ONLY : mp_sum, mp_bcast
USE mp_world, ONLY : world_comm
USE control_flags, ONLY : gamma_only
!USE exx, ONLY : exx_divergence_new, exx_grid_init, yukawa,exx_divergence_old
USE fft_base, ONLY : dfftp, dffts
USE fft_interfaces, ONLY : fwfft, invfft
USE fft_base, ONLY : dfftp
USE io_global, ONLY : ionode
USE lsda_mod, ONLY : nspin
implicit none
INTEGER, EXTERNAL :: find_free_unit
INTEGER, INTENT(in) :: nbnd_v(nspin) !number of valence states for both spin channels
INTEGER, INTENT(in) :: nbnd_s !number of states considered
INTEGER, INTENT(in) :: n_set !defines the number of states to be read from disk at the same time
REAL(kind=DP), INTENT(out) :: e_x(nbnd,nspin)!in output exchange energies
COMPLEX(kind=DP), INTENT(in) :: ks_wfcs(npwx,nbnd,nspin)!all kohn sham wavefunctions
REAL(kind=DP), ALLOCATABLE :: fac(:)
REAL(kind=DP) :: qq_fact,exxdiv
INTEGER :: ig,iiv,iv,jjs,js,hw,ks
REAL(kind=DP), ALLOCATABLE :: becpr(:,:)
REAL(kind=DP), ALLOCATABLE :: tmpreal1(:), tmpreal_v(:,:),tmpreal_s(:,:)
INTEGER :: igk0(npwx)
REAL(kind=dp) :: g2kin_bp(npwx)
INTEGER :: npw0
INTEGER :: jmin,jmax
COMPLEX(kind=DP), ALLOCATABLE :: prod_g(:),prod_c(:),prod_g2(:,:)
REAL(kind=DP), ALLOCATABLE :: prod_r(:)
REAL(kind=DP) :: exc
INTEGER :: iun
INTEGER, PARAMETER :: n_int=20
REAL(kind=DP) :: qx,qy,qz
INTEGER :: ix,iy,iz,n_int_loc,iunu
REAL(kind=DP), ALLOCATABLE :: e_x_off(:,:,:)
COMPLEX(kind=DP) :: c_exc
INTEGER :: isv
allocate(fac(ngm))
if(l_whole_s) then
allocate(e_x_off(nbnd_s,nbnd_s,nspin))
e_x_off(:,:,:)=0.d0
endif
!sets factors terms
!sets factors terms
!this has already been called call exx_grid_init()
if(l_truncated_coulomb) then
do ig=1,ngm
qq_fact = g(1,ig)**2.d0 + g(2,ig)**2.d0 + g(3,ig)**2.d0
if (qq_fact > 1.d-8) then
fac(ig)=(e2*fpi/(tpiba2*qq_fact))*(1.d0-dcos(dsqrt(qq_fact)*truncation_radius*tpiba))
else
fac(ig)=e2*fpi*(truncation_radius**2.d0/2.d0)
endif
end do
fac(:)=fac(:)/omega
else
fac(:)=0.d0
fac(1:npw)=vg_q(1:npw)
endif
e_x(:,:)=0.d0
CALL gk_sort(xk(1,1),ngm,g,gcutw,npw0,igk0,g2kin_bp)
allocate(tmpreal1(dfftp%nnr))
allocate(tmpreal_v(dfftp%nnr,n_set))
allocate(tmpreal_s(dfftp%nnr,n_set))
allocate(prod_g(ngm),prod_g2(ngm,nbnd_s))
allocate(prod_c(dfftp%nnr))
allocate(prod_r(dfftp%nnr))
!external loop on valence state
do isv=1,nspin
do iiv=1,ceiling(real(nbnd_v(isv))/real(n_set))
!read states and do fourier transform
do hw=(iiv-1)*n_set+1,min(iiv*n_set,nbnd_v(isv)),2
psic(:)=(0.d0,0.d0)
psic(:)=(0.d0,0.d0)
IF ( hw < min(iiv*n_set,nbnd_v(isv))) then
psic(nls(1:npw0)) = ks_wfcs(1:npw0,hw,isv) + &
( 0.D0, 1.D0 ) * ks_wfcs(1:npw0,hw+1,isv)
psic(nlsm(1:npw0)) = CONJG( ks_wfcs(1:npw,hw,isv) - &
( 0.D0, 1.D0 ) * ks_wfcs(1:npw0,hw+1,isv) )
ELSE
psic(nls(1:npw0)) = ks_wfcs(1:npw0,hw,isv)
psic(nlsm(1:npw0)) = CONJG( ks_wfcs(1:npw0,hw,isv) )
END IF
CALL invfft ('Wave', psic, dffts)
tmpreal1(1:dfftp%nnr)=dble(psic(1:dfftp%nnr))
if(doublegrid) then
call interpolate(tmpreal_v(:,hw-(iiv-1)*n_set),tmpreal1,1)
else
tmpreal_v(:,hw-(iiv-1)*n_set)=tmpreal1(:)
endif
if ( hw < min(iiv*n_set,nbnd_v(isv))) then
tmpreal1(1:dfftp%nnr)=aimag(psic(1:dfftp%nnr))
if(doublegrid) then
call interpolate(tmpreal_v(:,hw-(iiv-1)*n_set+1),tmpreal1,1)
else
tmpreal_v(:,hw-(iiv-1)*n_set+1)=tmpreal1(:)
endif
endif
enddo
do jjs=1,ceiling(real(nbnd_s)/real(n_set))
!external loop on states
!read states and do fourier transform
do hw=(jjs-1)*n_set+1,min(jjs*n_set,nbnd_s),2
psic(:)=(0.d0,0.d0)
psic(:)=(0.d0,0.d0)
IF ( hw < min(jjs*n_set,nbnd_s)) then
psic(nls(1:npw0)) = ks_wfcs(1:npw0,hw,isv) + &
( 0.D0, 1.D0 ) * ks_wfcs(1:npw0,hw+1,isv)
psic(nlsm(1:npw0)) = CONJG( ks_wfcs(1:npw,hw,isv) - &
( 0.D0, 1.D0 ) * ks_wfcs(1:npw0,hw+1,isv) )
ELSE
psic(nls(1:npw0)) = ks_wfcs(1:npw0,hw,isv)
psic(nlsm(1:npw0)) = CONJG( ks_wfcs(1:npw0,hw,isv) )
END IF
CALL invfft ('Wave', psic, dffts)
tmpreal1(1:dfftp%nnr)=dble(psic(1:dfftp%nnr))
if(doublegrid) then
call interpolate(tmpreal_s(:,hw-(jjs-1)*n_set),tmpreal1,1)
else
tmpreal_s(:,hw-(jjs-1)*n_set)=tmpreal1(:)
endif
if ( hw < min(jjs*n_set,nbnd_s)) then
tmpreal1(1:dfftp%nnr)=aimag(psic(1:dfftp%nnr))
if(doublegrid) then
call interpolate(tmpreal_s(:,hw-(jjs-1)*n_set+1),tmpreal1,1)
else
tmpreal_s(:,hw-(jjs-1)*n_set+1)=tmpreal1(:)
endif
endif
enddo
!internal loop on valence states
do iv=(iiv-1)*n_set+1,min(iiv*n_set,nbnd_v(isv))
jmin=(jjs-1)*n_set+1
jmax=min(jjs*n_set,nbnd_s)
!for whole X operator for given iv calculate products in real space with all the
!KS states and store in G space
if(l_whole_s) then
!NOT_TO_BE_INCLUDED_START
do ks=1,nbnd_s,1
psic(:)=(0.d0,0.d0)
psic(nls(1:npw0)) = ks_wfcs(1:npw0,ks,isv)
psic(nlsm(1:npw0)) = CONJG( ks_wfcs(1:npw0,ks,isv) )
CALL invfft ('Wave', psic, dffts)
prod_c(1:dfftp%nnr)=dcmplx(dble(psic(1:dfftp%nnr))*tmpreal_v(1:dfftp%nnr,iv-(iiv-1)*n_set)&
& ,0.d0)
CALL fwfft ('Dense', prod_c, dfftp)
prod_g2(1:ngm,ks)=prod_c(nl(1:ngm))
enddo
!NOT_TO_BE_INCLUDED_END
endif
do js=jmin,jmax
!do product in real speace
prod_r(:)=tmpreal_v(:,iv-(iiv-1)*n_set)*tmpreal_s(:,js-(jjs-1)*n_set)
! if(okvan) call adduspos_gamma_r & ATTENZIONE
! (iv,js, prod_r(:),1,becpr(:,iv),becpr(:,js))
prod_c(:)=dcmplx(prod_r(:),0.d0)
CALL fwfft ('Dense', prod_c, dfftp)
!go to g_space
prod_g(1:ngm)=prod_c(nl(1:ngm))
!calculated exchange
exc=0.d0
do ig=1,ngm
exc=exc+2.d0*dble(conjg(prod_g(ig))*prod_g(ig))*fac(ig)*wg(iv,isv)*dble(nspin)/2.d0
enddo
if(gstart==2) exc=exc-dble(prod_g(1))*dble(prod_g(1))*fac(1)*wg(iv,isv)*dble(nspin)/2.d0
call mp_sum(exc,world_comm)
exc=-exc
e_x(js,isv)=e_x(js,isv)+exc
!poor programmer solution for off diagonal terms....
!ONLY FOR NORMCONSERVING PSEUDOS
if(l_whole_s) then
!NOT_TO_BE_INCLUDED_START
write(stdout,*) 'Call complete X operator part',iv
FLUSH(stdout)
do ks=1,nbnd_s,1
c_exc=(0.d0,0.d0)
do ig=1,ngm
c_exc=c_exc+conjg(prod_g2(ig,ks))*prod_g(ig)*fac(ig)+&
&prod_g2(ig,ks)*conjg(prod_g(ig))*fac(ig)
enddo
if(gstart==2) c_exc=c_exc-conjg(prod_g2(1,ks))*prod_g(1)*fac(1)
call mp_sum(c_exc,world_comm)
c_exc=-c_exc
e_x_off(ks,js,isv)=e_x_off(ks,js,isv)+dble(c_exc)
enddo
!NOT_TO_BE_INCLUDED_END
endif
enddo
enddo
enddo
enddo
enddo!ivv
do isv=1,nspin
do iv=1,nbnd_s
write(stdout,*) 'Exchange energy', iv,isv, e_x(iv,isv)
enddo
enddo
!write on file
if(ionode) then
iun = find_free_unit()
open(unit=iun,file=trim(tmp_dir)//trim(prefix)//'.exchange',status='unknown',form='unformatted')
write(iun) nbnd_s
do isv=1,nspin
!NOT_TO_BE_INCLUDED_START
if(l_selfconsistent) e_x(1:nbnd_s,isv)=0.d0
!NOT_TO_BE_INCLUDED_END
write(iun) e_x(1:nbnd_s,isv)
enddo
close(iun)
endif
!if required write on disk off-diagonal terms
if(l_whole_s) then
!NOT_TO_BE_INCLUDED_START
if(ionode) then
do iv=1,nbnd_s
write(stdout,*) 'Exchange energy off', iv, e_x_off(iv,iv,1)
enddo
!write on file
iun = find_free_unit()
open(unit=iun,file=trim(tmp_dir)//trim(prefix)//'.exchange_off',status='unknown',form='unformatted')
write(iun) nbnd_s
do isv=1,nspin
do js=1,nbnd_s
write(iun) e_x_off(1:nbnd_s,js,isv)
enddo
enddo
close(iun)
endif
!NOT_TO_BE_INCLUDED_END
endif
deallocate(tmpreal1,tmpreal_s,tmpreal_v)
deallocate(fac)
deallocate(prod_c,prod_g,prod_g2)
deallocate(prod_r)
if(okvan) deallocate(becpr)
if(l_whole_s) then
!NOT_TO_BE_INCLUDED_START
deallocate(e_x_off)
!NOT_TO_BE_INCLUDED_END
endif
end subroutine dft_exchange
!----------------------------------------------------------------------
subroutine addus_charge(r_ij,becp_iw,becp_jw)
!----------------------------------------------------------------------
!
! 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 gvect, ONLY : ngm, nl, nlm, gg, g, eigts1, eigts2, &
eigts3, mill
USE lsda_mod, ONLY : nspin
USE scf, ONLY : rho
USE uspp, ONLY : okvan, nkb
USE uspp_param, ONLY : lmaxq, upf, nh
USE wavefunctions_module, ONLY : psic
USE control_flags , ONLY : gamma_only
USE fft_base, ONLY : dfftp, dffts
USE fft_interfaces, ONLY : fwfft, invfft
!
implicit none
COMPLEX(kind=DP), INTENT(inout) :: r_ij(dfftp%nnr)!where to add the us term
COMPLEX(kind=DP), INTENT(in) :: becp_iw( nkb)!overlap of wfcs with us projectors
COMPLEX(kind=DP), INTENT(in) :: becp_jw( nkb)!overlap of wfcs with us projectors
!
! here the local variables
!
integer :: ig, na, nt, ih, jh, 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
INTEGER, ALLOCATABLE :: ind_cor(:,:,:)
INTEGER :: ijkb0, ikb,np
if (.not.okvan) return
allocate (aux ( ngm, nspin))
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
!found index correspondence
allocate(ind_cor(ntyp,nat,maxval(nh(1:ntyp))))
ijkb0 = 0
do np = 1, ntyp
if ( upf(np)%tvanp ) then
do na = 1, nat
if ( ityp(na) == np ) then
do ih = 1, nh(np)
ikb = ijkb0 + ih
ind_cor(np,na,ih)=ikb
enddo
ijkb0=ijkb0+nh(np)
endif
enddo
else
do na=1,nat
if(ityp(na) == np) ijkb0=ijkb0+nh(np)
enddo
endif
enddo
do nt = 1, ntyp
if (upf(nt)%tvanp ) then
do ih = 1, nh (nt)
do jh = 1, nh (nt)
call qvan2 (ngm, ih, jh, nt, qmod, qgm, ylmk0)
do na = 1, nat
if (ityp (na) .eq.nt) then
!
! Multiply becsum and qg with the correct structure factor
!
do is = 1, nspin
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*&
&conjg(becp_iw(ind_cor(nt,na,ih)))*becp_jw(ind_cor(nt,na,jh))
enddo
enddo
endif
enddo
enddo
enddo
endif
enddo
deallocate(ind_cor)
!
deallocate (ylmk0)
deallocate (qgm)
deallocate (qmod)
!
! convert aux to real space and add to the charge density
!
do is = 1, nspin!SPIN TO BE IMPLEMENTED YET
psic(:) = (0.d0, 0.d0)
psic( nl(:) ) = aux(:,is)
if (gamma_only) psic( nlm(:) ) = CONJG(aux(:,is))
CALL invfft ('Dense', psic, dfftp)
r_ij(:)=r_ij(:)+psic(:)
enddo
deallocate (aux)
return
end subroutine addus_charge
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