mirror of https://gitlab.com/QEF/q-e.git
126 lines
4.5 KiB
Fortran
126 lines
4.5 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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subroutine setup_dgc
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!-----------------------------------------------------------------------
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! Allocate and setup all variable needed in the gradient correction case
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!
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! GGA+LSDA is allowed. AdC (September 1999).
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! GGA+LSDA+NLCC is allowed. AdC (November 1999).
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!
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#include "f_defs.h"
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use pwcom
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USE kinds, only : DP
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use phcom
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use funct, only : dft_is_gradient, gcxc, gcx_spin, gcc_spin
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implicit none
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integer :: k, is
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real(DP) :: grho2 (2), rh, zeta, grh2, fac, sx, sc, &
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v1x, v2x, v1c, v2c, vrrx, vsrx, vssx, vrrc, vsrc, vssc, v1xup, &
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v1xdw, v2xup, v2xdw, v1cup, v1cdw, vrrxup, vrrxdw, vrsxup, vrsxdw, &
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vssxup, vssxdw, vrrcup, vrrcdw, vrscup, vrscdw, vrzcup, vrzcdw
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real (DP), parameter :: epsr = 1.0d-6, epsg = 1.0d-10
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if ( .not. dft_is_gradient() ) return
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allocate (dvxc_rr( nrxx , nspin , nspin))
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allocate (dvxc_sr( nrxx , nspin , nspin))
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allocate (dvxc_ss( nrxx , nspin , nspin))
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allocate (dvxc_s ( nrxx , nspin , nspin))
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allocate (grho ( 3 , nrxx , nspin))
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dvxc_rr(:,:,:) = 0.d0
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dvxc_sr(:,:,:) = 0.d0
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dvxc_ss(:,:,:) = 0.d0
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dvxc_s (:,:,:) = 0.d0
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grho (:,:,:) = 0.d0
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!
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! add rho_core
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!
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fac = 1.d0 / DBLE (nspin)
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if (nlcc_any) then
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do is = 1, nspin
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do k = 1, nrxx
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rho (k, is) = rho (k, is) + rho_core (k) * fac
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enddo
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enddo
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endif
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do is = 1, nspin
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call gradient (nrx1, nrx2, nrx3, nr1, nr2, nr3, nrxx, rho (1, is), &
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ngm, g, nl, alat, grho (1, 1, is) )
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enddo
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do k = 1, nrxx
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grho2 (1) = grho (1, k, 1) **2 + grho (2, k, 1) **2 + grho (3, k, 1) **2
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if (nspin == 1) then
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if (abs (rho (k, 1) ) > epsr .and. grho2 (1) > epsg) then
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call gcxc (rho (k, nspin), grho2(1), sx, sc, v1x, v2x, v1c, v2c)
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call dgcxc (rho (k, nspin), grho2, vrrx, vsrx, vssx, vrrc, &
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vsrc, vssc)
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dvxc_rr (k, 1, 1) = e2 * (vrrx + vrrc)
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dvxc_sr (k, 1, 1) = e2 * (vsrx + vsrc)
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dvxc_ss (k, 1, 1) = e2 * (vssx + vssc)
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dvxc_s (k, 1, 1) = e2 * (v2x + v2c)
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endif
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else
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grho2 (2) = grho (1, k, 2) **2 + grho (2, k, 2) **2 + grho (3, &
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k, 2) **2
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rh = rho (k, 1) + rho (k, 2)
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grh2 = (grho (1, k, 1) + grho (1, k, 2) ) **2 + (grho (2, k, 1) &
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+ grho (2, k, 2) ) **2 + (grho (3, k, 1) + grho (3, k, 2) ) ** 2
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call gcx_spin (rho (k, 1), rho (k, 2), grho2 (1), grho2 (2), &
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sx, v1xup, v1xdw, v2xup, v2xdw)
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call dgcxc_spin (rho (k, 1), rho (k, 2), grho (1, k, 1), &
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grho (1, k, 2), vrrxup, vrrxdw, vrsxup, vrsxdw, vssxup, vssxdw, &
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vrrcup, vrrcdw, vrscup, vrscdw, vssc, vrzcup, vrzcdw)
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if (rh > epsr) then
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zeta = (rho (k, 1) - rho (k, 2) ) / rh
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call gcc_spin (rh, zeta, grh2, sc, v1cup, v1cdw, v2c)
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dvxc_rr (k, 1, 1) = e2 * (vrrxup + vrrcup + vrzcup * &
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(1.d0 - zeta) / rh)
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dvxc_rr (k, 1, 2) = e2 * (vrrcup - vrzcup * (1.d0 + zeta) / rh)
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dvxc_rr (k, 2, 1) = e2 * (vrrcdw + vrzcdw * (1.d0 - zeta) / rh)
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dvxc_rr (k, 2, 2) = e2 * (vrrxdw + vrrcdw - vrzcdw * &
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(1.d0 + zeta) / rh)
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dvxc_s (k, 1, 1) = e2 * (v2xup + v2c)
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dvxc_s (k, 1, 2) = e2 * v2c
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dvxc_s (k, 2, 1) = e2 * v2c
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dvxc_s (k, 2, 2) = e2 * (v2xdw + v2c)
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else
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dvxc_rr (k, 1, 1) = 0.d0
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dvxc_rr (k, 1, 2) = 0.d0
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dvxc_rr (k, 2, 1) = 0.d0
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dvxc_rr (k, 2, 2) = 0.d0
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dvxc_s (k, 1, 1) = 0.d0
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dvxc_s (k, 1, 2) = 0.d0
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dvxc_s (k, 2, 1) = 0.d0
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dvxc_s (k, 2, 2) = 0.d0
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endif
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dvxc_sr (k, 1, 1) = e2 * (vrsxup + vrscup)
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dvxc_sr (k, 1, 2) = e2 * vrscup
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dvxc_sr (k, 2, 1) = e2 * vrscdw
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dvxc_sr (k, 2, 2) = e2 * (vrsxdw + vrscdw)
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dvxc_ss (k, 1, 1) = e2 * (vssxup + vssc)
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dvxc_ss (k, 1, 2) = e2 * vssc
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dvxc_ss (k, 2, 1) = e2 * vssc
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dvxc_ss (k, 2, 2) = e2 * (vssxdw + vssc)
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endif
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enddo
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if (nlcc_any) then
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do is = 1, nspin
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do k = 1, nrxx
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rho (k, is) = rho (k, is) - rho_core (k) * fac
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enddo
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enddo
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endif
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return
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end subroutine setup_dgc
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