mirror of https://gitlab.com/QEF/q-e.git
107 lines
3.1 KiB
Fortran
107 lines
3.1 KiB
Fortran
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! Copyright (C) 2001-2007 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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!----------------------------------------------------------------------
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subroutine stres_loc (sigmaloc)
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!----------------------------------------------------------------------
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!
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USE kinds, ONLY : DP
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USE atom, ONLY : msh, rgrid
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USE ions_base, ONLY : ntyp => nsp
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USE cell_base, ONLY : omega, tpiba2
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USE fft_base, ONLY : dfftp
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USE fft_interfaces, ONLY : fwfft
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USE gvect, ONLY : ngm, gstart, nl, g, ngl, gl, igtongl
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USE lsda_mod, ONLY : nspin
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USE scf, ONLY : rho
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USE vlocal, ONLY : strf, vloc
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USE control_flags, ONLY : gamma_only
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USE wavefunctions_module, ONLY : psic
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USE uspp_param, ONLY : upf
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USE noncollin_module, ONLY : nspin_lsda
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USE mp_global, ONLY : intra_pool_comm
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USE mp, ONLY : mp_sum
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!
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implicit none
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!
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real(DP) :: sigmaloc (3, 3)
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real(DP) , allocatable :: dvloc(:)
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real(DP) :: evloc, fact
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integer :: ng, nt, l, m, is
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! counter on g vectors
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! counter on atomic type
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! counter on angular momentum
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! counter on spin components
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allocate(dvloc(ngl))
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sigmaloc(:,:) = 0.d0
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psic(:)=(0.d0,0.d0)
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do is = 1, nspin_lsda
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call daxpy (dfftp%nnr, 1.d0, rho%of_r (1, is), 1, psic, 2)
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enddo
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CALL fwfft ('Dense', psic, dfftp)
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! psic contains now the charge density in G space
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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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evloc = 0.0d0
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do nt = 1, ntyp
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if (gstart==2) evloc = evloc + &
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psic (nl (1) ) * strf (1, nt) * vloc (igtongl (1), nt)
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do ng = gstart, ngm
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evloc = evloc + DBLE (CONJG(psic (nl (ng) ) ) * strf (ng, nt) ) &
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* vloc (igtongl (ng), nt) * fact
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enddo
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enddo
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!
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! WRITE( 6,*) ' evloc ', evloc, evloc*omega ! DEBUG
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!
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do nt = 1, ntyp
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IF ( .NOT. ASSOCIATED ( upf(nt)%vloc ) ) THEN
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!
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! special case: pseudopotential is coulomb 1/r potential
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!
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call dvloc_coul (upf(nt)%zp, tpiba2, ngl, gl, omega, dvloc)
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!
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ELSE
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!
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! normal case: dvloc contains dV_loc(G)/dG
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!
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call dvloc_of_g (rgrid(nt)%mesh, msh (nt), rgrid(nt)%rab, rgrid(nt)%r,&
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upf(nt)%vloc(1), upf(nt)%zp, tpiba2, ngl, gl, omega, dvloc)
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!
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END IF
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! no G=0 contribution
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do ng = 1, ngm
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do l = 1, 3
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do m = 1, l
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sigmaloc(l, m) = sigmaloc(l, m) + DBLE( CONJG( psic(nl(ng) ) ) &
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* strf (ng, nt) ) * 2.0d0 * dvloc (igtongl (ng) ) &
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* tpiba2 * g (l, ng) * g (m, ng) * fact
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enddo
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enddo
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enddo
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enddo
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!
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do l = 1, 3
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sigmaloc (l, l) = sigmaloc (l, l) + evloc
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do m = 1, l - 1
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sigmaloc (m, l) = sigmaloc (l, m)
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enddo
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enddo
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#ifdef __PARA
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call mp_sum( sigmaloc, intra_pool_comm )
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#endif
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deallocate(dvloc)
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return
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end subroutine stres_loc
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