mirror of https://gitlab.com/QEF/q-e.git
115 lines
3.6 KiB
Fortran
115 lines
3.6 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 adddvscf (ipert, ik)
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!----------------------------------------------------------------------
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!
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! This routine computes the contribution of the selfconsistent
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! change of the potential to the known part of the linear
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! system and adds it to dvpsi.
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! It implements the second term in Eq. B30 of PRB 64, 235118 (2001).
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!
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USE kinds, ONLY : DP
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USE uspp_param, ONLY : upf, nh
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USE uspp, ONLY : vkb, okvan
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! modules from pwcom
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USE lsda_mod, ONLY : lsda, current_spin, isk
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USE ions_base, ONLY : ntyp => nsp, nat, ityp
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USE wvfct, ONLY : nbnd, npwx
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USE noncollin_module, ONLY : noncolin, npol
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! modules from phcom
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USE lrus, ONLY : int3, int3_nc, becp1
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USE qpoint, ONLY : npwq, ikks
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USE eqv, ONLY : dvpsi
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implicit none
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!
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! The dummy variables
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!
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integer :: ik, ipert
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! input: the k point
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! input: the perturbation
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!
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! And the local variables
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!
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integer :: na, nt, ibnd, ih, jh, ijkb0, ikk, ikb, jkb, is, js, ijs
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! counter on atoms
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! counter on atomic types
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! counter on bands
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! counter on beta functions
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! counter on beta functions
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! auxiliary variable for indexing
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! counter on the k points
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! counter on vkb
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! counter on vkb
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complex(DP) :: sum, sum_nc(npol)
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! auxiliary variable
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if (.not.okvan) return
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call start_clock ('adddvscf')
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ikk = ikks(ik)
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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) .eq.nt) then
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!
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! we multiply the integral for the becp term and the beta_n
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!
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do ibnd = 1, nbnd
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do ih = 1, nh (nt)
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ikb = ijkb0 + ih
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IF (noncolin) THEN
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sum_nc = (0.d0, 0.d0)
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ELSE
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sum = (0.d0, 0.d0)
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END IF
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do jh = 1, nh (nt)
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jkb = ijkb0 + jh
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IF (noncolin) THEN
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ijs=0
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do is=1,npol
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do js=1,npol
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ijs=ijs+1
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sum_nc(is)=sum_nc(is)+ &
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int3_nc(ih,jh,na,ijs,ipert)* &
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becp1(ik)%nc(jkb, js, ibnd)
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enddo
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enddo
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ELSE
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sum = sum + int3 (ih, jh, na, current_spin, ipert)*&
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becp1(ik)%k(jkb, ibnd)
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END IF
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enddo
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IF (noncolin) THEN
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call zaxpy(npwq,sum_nc(1),vkb(1,ikb),1,dvpsi(1,ibnd),1)
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call zaxpy(npwq,sum_nc(2),vkb(1,ikb),1, &
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dvpsi(1+npwx,ibnd),1)
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ELSE
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call zaxpy(npwq,sum,vkb(1,ikb),1,dvpsi(1,ibnd),1)
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END IF
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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) .eq.nt) ijkb0 = ijkb0 + nh (nt)
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enddo
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endif
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enddo
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call stop_clock ('adddvscf')
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return
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end subroutine adddvscf
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