mirror of https://gitlab.com/QEF/q-e.git
106 lines
3.5 KiB
Fortran
106 lines
3.5 KiB
Fortran
!
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! Copyright (C) 2001-2008 Quantum ESPRESSO 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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subroutine sym_dmage (dvsym)
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!---------------------------------------------------------------------
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!
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! This routine symmetrize the change of the potential due to an
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! electric field perturbation. It is assumed that the perturbations
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! are on the basis of the crystal
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!
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!
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USE kinds, only : DP
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USE cell_base,only : at, bg
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USE grid_dimensions, only : nr1,nr2,nr3, nr1x,nr2x,nr3x
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USE symm_base,only : nsym, sname, s, ftau, t_rev, invs
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USE lsda_mod, only : nspin
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implicit none
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complex(DP) :: dvsym (nr1x, nr2x, nr3x, nspin, 3)
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complex(DP), allocatable :: aux (:,:,:,:,:)
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complex(DP) :: dmags(3,3), mag(3), magrot(3)
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! the potential to symmetrize
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! auxiliary quantity
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integer :: is, ri, rj, rk, i, j, k, irot, ipol, jpol, kpol
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! counter on spin polarization
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! the rotated points
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! the point
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! counter on symmetries
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! counter on polarizations
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do is = 2,4
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do ipol = 1, 3
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dvsym(:,:,:,is,ipol) = CMPLX(DBLE(dvsym(:,:,:,is,ipol)),0.d0,kind=DP)
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end do
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end do
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if (nsym == 1) return
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allocate (aux(nr1x , nr2x , nr3x , 3, 3))
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do is = 2, 4
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do ipol = 1, 3
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aux(:,:,:,is-1,ipol) = dvsym(:,:,:,is,ipol)
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dvsym(:,:,:,is,ipol) = (0.d0, 0.d0)
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enddo
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enddo
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!
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! symmmetrize
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!
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do k = 1, nr3
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do j = 1, nr2
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do i = 1, nr1
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do irot = 1, nsym
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call ruotaijk (s(1,1,irot), ftau(1,irot), i, j, k, &
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nr1, nr2, nr3, ri, rj, rk)
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!
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! ruotaijk find the rotated of i,j,k with the inverse of S
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!
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dmags=(0.d0,0.d0)
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do ipol = 1, 3
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do is=1,3
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do jpol = 1, 3
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dmags(is,ipol)=dmags(is,ipol) + &
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s(ipol,jpol,irot) * aux(ri,rj,rk,is,jpol)
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enddo
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enddo
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do kpol = 1, 3
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mag(kpol)=bg(1,kpol)*dmags(1,ipol) + &
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bg(2,kpol)*dmags(2,ipol) + &
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bg(3,kpol)*dmags(3,ipol)
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enddo
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! rotate the magnetic moment
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do kpol = 1, 3
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magrot(kpol) = s(1,kpol,invs(irot))*mag(1) + &
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s(2,kpol,invs(irot))*mag(2) + &
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s(3,kpol,invs(irot))*mag(3)
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enddo
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if (sname(irot)(1:3)=='inv') magrot=-magrot
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if(t_rev(irot).eq.1) magrot=-magrot
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! go back to cartesian coordinates
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do kpol = 1, 3
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mag(kpol)=at(kpol,1)*magrot(1) + &
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at(kpol,2)*magrot(2) + &
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at(kpol,3)*magrot(3)
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enddo
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dvsym(i,j,k,2,ipol) = dvsym(i,j,k,2,ipol) + mag(1)
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dvsym(i,j,k,3,ipol) = dvsym(i,j,k,3,ipol) + mag(2)
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dvsym(i,j,k,4,ipol) = dvsym(i,j,k,4,ipol) + mag(3)
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enddo
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enddo
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enddo
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enddo
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enddo
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do is=2,4
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do ipol = 1, 3
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dvsym(:,:,:,is,ipol) = dvsym(:,:,:,is,ipol) / DBLE(nsym)
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enddo
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enddo
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deallocate (aux)
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return
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end subroutine sym_dmage
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