mirror of https://gitlab.com/QEF/q-e.git
157 lines
5.5 KiB
Fortran
157 lines
5.5 KiB
Fortran
!
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! Copyright (C) 2001 PWSCF group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!
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!-----------------------------------------------------------------------
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subroutine compute_alphasum
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!-----------------------------------------------------------------------
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!
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! This routine computes the alphasum term which is used to compute the
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! change of the charge due to the displacement of the augmentation
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! term. (See Eq. 29)
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! It implements Eq.13 of the notes.
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!
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!
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#include "f_defs.h"
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USE ions_base, ONLY : nat, ityp, ntyp => nsp
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use pwcom
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USE noncollin_module, ONLY : noncolin, npol
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USE kinds, only : DP
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USE uspp, ONLY: okvan
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USE uspp_param, ONLY: upf, nh
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use phcom
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implicit none
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integer :: ik, ikk, ikq, ijkb0, ijh, ikb, jkb, ih, jh, na, nt, &
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ipol, ibnd, is1, is2
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! counter on k points
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! counters on beta functions
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! counters on beta functions
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! counters for atoms
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! counter on polarizations
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! counter on bands
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real(DP) :: wgg1
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! auxiliary weight
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if (.not.okvan) return
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alphasum = 0.d0
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IF (noncolin) alphasum_nc=(0.d0,0.d0)
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do ik = 1, nksq
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if (lgamma) then
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ikk = ik
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ikq = ik
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else
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ikk = 2 * ik - 1
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ikq = ikk + 1
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endif
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if (lsda) current_spin = isk (ikk)
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ijkb0 = 0
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do nt = 1, ntyp
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if (upf(nt)%tvanp ) then
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do na = 1, nat
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if (ityp (na) == nt) then
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ijh = 0
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do ih = 1, nh (nt)
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ikb = ijkb0 + ih
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ijh = ijh + 1
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do ibnd = 1, nbnd_occ (ikk)
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wgg1 = wg (ibnd, ikk)
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do ipol = 1, 3
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IF (noncolin) THEN
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DO is1=1,npol
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DO is2=1,npol
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alphasum_nc(ijh,ipol,na,is1,is2) = &
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alphasum_nc(ijh,ipol,na,is1,is2)+wgg1* &
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(CONJG(alphap_nc(ikb,is1,ibnd,ipol,ik))*&
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becp1_nc(ikb,is2,ibnd,ik) + &
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CONJG(becp1_nc(ikb,is1,ibnd,ik))* &
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alphap_nc(ikb,is2,ibnd,ipol,ik))
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END DO
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END DO
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ELSE
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alphasum(ijh,ipol,na,current_spin) = &
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alphasum(ijh,ipol,na,current_spin) + 2.d0*wgg1*&
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DBLE (CONJG(alphap (ikb,ibnd,ipol,ik) ) * &
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becp1 (ikb,ibnd,ik) )
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END IF
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enddo
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enddo
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do jh = ih+1, nh (nt)
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jkb = ijkb0 + jh
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ijh = ijh + 1
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do ibnd = 1, nbnd
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wgg1 = wg (ibnd, ikk)
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do ipol = 1, 3
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IF (noncolin) THEN
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DO is1=1,npol
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DO is2=1,npol
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alphasum_nc(ijh,ipol,na,is1,is2) = &
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alphasum_nc(ijh,ipol,na,is1,is2) &
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+wgg1* &
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(CONJG(alphap_nc(ikb,is1,ibnd,ipol,ik))* &
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becp1_nc(jkb,is2,ibnd,ik)+ &
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CONJG(becp1_nc(ikb,is1,ibnd,ik))* &
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alphap_nc(jkb,is2,ibnd,ipol,ik) )
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END DO
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END DO
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ELSE
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alphasum(ijh,ipol,na,current_spin) = &
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alphasum(ijh,ipol,na,current_spin) + &
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2.d0 * wgg1 * &
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DBLE (CONJG(alphap(ikb,ibnd,ipol,ik) )*&
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becp1 (jkb,ibnd,ik) + &
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CONJG( becp1 (ikb,ibnd,ik) ) * &
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alphap (jkb,ibnd,ipol,ik) )
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END IF
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enddo
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enddo
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enddo
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enddo
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ijkb0 = ijkb0 + nh (nt)
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endif
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enddo
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else
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do na = 1, nat
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if (ityp (na) == nt) ijkb0 = ijkb0 + nh (nt)
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enddo
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endif
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enddo
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enddo
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IF (noncolin.and.okvan) THEN
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DO nt = 1, ntyp
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IF ( upf(nt)%tvanp ) THEN
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DO na = 1, nat
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IF (ityp(na)==nt) THEN
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IF (upf(nt)%has_so) THEN
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CALL transform_alphasum_so(alphasum_nc,na)
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ELSE
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CALL transform_alphasum_nc(alphasum_nc,na)
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END IF
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END IF
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END DO
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END IF
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END DO
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END IF
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! do na=1,nat
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! nt=ityp(na)
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! do ijh=1,nh(nt)*(nh(nt)+1)/2
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! do ipol=1,3
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! WRITE( stdout,'(3i5,f20.10)') na, ijh, ipol,
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! + alphasum(ijh,ipol,na,1)
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! enddo
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! enddo
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! enddo
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! call stop_ph(.true.)
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return
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end subroutine compute_alphasum
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