mirror of https://gitlab.com/QEF/q-e.git
147 lines
4.5 KiB
Fortran
147 lines
4.5 KiB
Fortran
!
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! Copyright (C) 2001-2003 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 addusforce (forcenl)
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!----------------------------------------------------------------------
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!
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! This routine computes the contribution to atomic forces due
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! to the dependence of the Q function on the atomic position.
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! On output: the contribution is added to forcenl
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!
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#include "machine.h"
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USE kinds, ONLY: DP
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USE basis, ONLY : nat, ntyp, ityp
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USE cell_base, ONLY: omega, tpiba
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USE gvect, ONLY: nr1, nr2, nr3, nrx1, nrx2, nrx3, nrxx, ngm, &
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nl, nlm, gg, g, eigts1, eigts2, eigts3, ig1, ig2, ig3
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USE lsda_mod, ONLY: nspin
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USE scf, ONLY: vr, vltot
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USE us, ONLY : okvan, nh, nhm, becsum, tvanp
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USE uspp_param, ONLY : lqx
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USE wvfct, ONLY: gamma_only
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implicit none
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real(kind=DP) :: forcenl (3, nat)
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! local variables
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integer :: ig, ir, dim, nt, ih, jh, ijh, ipol, is, na
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complex(kind=DP):: cfac
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real(kind=DP) :: fact, DDOT
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! work space
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complex(kind=DP), allocatable :: aux(:,:), aux1(:,:), vg(:), qgm(:)
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real(kind=DP) , allocatable :: ddeeq(:,:,:,:), qmod(:), ylmk0(:,:)
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!
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if (.not.okvan) return
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!
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if (gamma_only) then
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fact = 2.d0
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else
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fact = 1.d0
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end if
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allocate (aux(ngm,nspin))
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!
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! fourier transform of the total effective potential
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!
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allocate (vg(nrxx))
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do is = 1, nspin
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if (nspin.eq.4.and.is.ne.1) then
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vg (:) = vr(:,is)
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else
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vg (:) = vltot (:) + vr (:, is)
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endif
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call cft3 (vg, nr1, nr2, nr3, nrx1, nrx2, nrx3, - 1)
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aux (:, is) = vg (nl (:) ) * tpiba * (0.d0, -1.d0)
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enddo
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deallocate (vg)
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!
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allocate (aux1(ngm,3))
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allocate (ddeeq( 3, (nhm*(nhm+1))/2,nat,nspin))
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allocate (qgm( ngm))
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allocate (qmod( ngm))
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allocate (ylmk0(ngm,lqx*lqx))
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!
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ddeeq(:,:,:,:) = 0.d0
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!
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call ylmr2 (lqx * lqx, ngm, g, gg, ylmk0)
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!
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qmod (:) = sqrt (gg (:) )
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!
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! here we compute the integral Q*V for each atom,
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! I = sum_G i G_a exp(-iR.G) Q_nm v^*
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!
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do nt = 1, ntyp
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if (tvanp (nt) ) then
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ijh = 1
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do ih = 1, nh (nt)
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do jh = ih, nh (nt)
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call qvan2 (ngm, ih, jh, nt, qmod, qgm, ylmk0)
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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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! The product of potential, structure factor and iG
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!
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do is = 1, nspin
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do ig = 1, ngm
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cfac = aux (ig, is) * conjg (eigts1 (ig1 (ig), na) *&
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eigts2 (ig2 (ig), na) *&
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eigts3 (ig3 (ig), na) )
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aux1 (ig, 1) = g (1, ig) * cfac
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aux1 (ig, 2) = g (2, ig) * cfac
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aux1 (ig, 3) = g (3, ig) * cfac
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enddo
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!
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! and the product with the Q functions
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! G=0 term gives no contribution
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!
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do ipol = 1, 3
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ddeeq (ipol, ijh, na, is) = omega * fact * &
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DDOT (2 * ngm, aux1 (1, ipol), 1, qgm, 1)
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enddo
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enddo
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endif
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enddo
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ijh = ijh + 1
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enddo
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enddo
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endif
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enddo
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#ifdef __PARA
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call reduce (3 * nhm * (nhm + 1) * nat * nspin / 2, ddeeq)
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#endif
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! WRITE( stdout,'( "dmatrix atom ",i4)') na
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! do ih = 1, nh(nt)
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! WRITE( stdout,'(8f9.4)') (ddeeq(ipol,ih,jh,na),jh=1,nh(nt))
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! end do
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! WRITE( stdout,'( "dion pseudo ",i4)') nt
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! do ih = 1, nh(nt)
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! WRITE( stdout,'(8f9.4)') (dvan(ih,jh,1,nt),jh=1,nh(nt))
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! end do
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do is = 1, nspin
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do na = 1, nat
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nt = ityp (na)
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dim = (nh (nt) * (nh (nt) + 1) ) / 2
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do ipol = 1, 3
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do ir = 1, dim
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forcenl (ipol, na) = forcenl (ipol, na) + &
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ddeeq (ipol, ir, na, is) * becsum (ir, na, is)
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enddo
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enddo
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enddo
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enddo
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deallocate (ylmk0)
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deallocate (qgm)
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deallocate (qmod)
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deallocate (ddeeq)
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deallocate (aux1)
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deallocate (aux)
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return
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end subroutine addusforce
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