mirror of https://gitlab.com/QEF/q-e.git
150 lines
4.3 KiB
Fortran
150 lines
4.3 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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#include "f_defs.h"
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!
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!----------------------------------------------------------------------
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subroutine gen_us_dy (ik, u, dvkb)
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!----------------------------------------------------------------------
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!
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! Calculates the kleinman-bylander pseudopotentials with the
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! derivative of the spherical harmonics projected on vector u
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!
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USE kinds, ONLY : DP
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USE io_global, ONLY : stdout
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USE constants, ONLY : tpi
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USE ions_base, ONLY : nat, ntyp => nsp, ityp, tau
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USE cell_base, ONLY : tpiba
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USE klist, ONLY : xk
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USE gvect, ONLY : ig1, ig2, ig3, eigts1, eigts2, eigts3, g
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USE wvfct, ONLY : npw, npwx, igk
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USE uspp, ONLY : nkb, indv, nhtol, nhtolm
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USE us, ONLY : nqx, tab, tab_d2y, dq, spline_ps
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USE splinelib
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USE uspp_param, ONLY : upf, lmaxkb, nbetam, nh
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!
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implicit none
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!
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integer :: ik
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real(DP) :: u (3)
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complex(DP) :: dvkb (npwx, nkb)
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integer :: na, nt, nb, ih, l, lm, ikb, iig, ipol, i0, i1, i2, &
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i3, ig
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real(DP), allocatable :: gk(:,:), q (:)
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real(DP) :: px, ux, vx, wx, arg
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real(DP), allocatable :: vkb0 (:,:,:), dylm (:,:), dylm_u (:,:)
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! dylm = d Y_lm/dr_i in cartesian axes
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! dylm_u as above projected on u
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complex(DP), allocatable :: sk (:)
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complex(DP) :: phase, pref
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integer :: iq
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real(DP), allocatable :: xdata(:)
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dvkb(:,:) = (0.d0, 0.d0)
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if (lmaxkb.le.0) return
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allocate ( vkb0(npw,nbetam,ntyp), dylm_u(npw,(lmaxkb+1)**2), gk(3,npw) )
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allocate ( q(npw) )
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do ig = 1, npw
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gk (1, ig) = xk (1, ik) + g (1, igk (ig) )
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gk (2, ig) = xk (2, ik) + g (2, igk (ig) )
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gk (3, ig) = xk (3, ik) + g (3, igk (ig) )
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q (ig) = gk(1, ig)**2 + gk(2, ig)**2 + gk(3, ig)**2
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enddo
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allocate ( dylm(npw,(lmaxkb+1)**2) )
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dylm_u(:,:) = 0.d0
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do ipol = 1, 3
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call dylmr2 ((lmaxkb+1)**2, npw, gk, q, dylm, ipol)
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call DAXPY (npw * (lmaxkb + 1) **2, u (ipol), dylm, 1, dylm_u, 1)
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enddo
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deallocate (dylm)
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do ig = 1, npw
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q (ig) = sqrt ( q(ig) ) * tpiba
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end do
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if (spline_ps) then
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allocate(xdata(nqx))
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do iq = 1, nqx
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xdata(iq) = (iq - 1) * dq
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enddo
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endif
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do nt = 1, ntyp
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! calculate beta in G-space using an interpolation table
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do nb = 1, upf(nt)%nbeta
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do ig = 1, npw
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if (spline_ps) then
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vkb0(ig,nb,nt) = splint(xdata, tab(:,nb,nt), &
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tab_d2y(:,nb,nt), q(ig))
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else
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px = q (ig) / dq - int (q (ig) / dq)
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ux = 1.d0 - px
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vx = 2.d0 - px
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wx = 3.d0 - px
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i0 = q (ig) / dq + 1
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i1 = i0 + 1
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i2 = i0 + 2
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i3 = i0 + 3
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vkb0 (ig, nb, nt) = tab (i0, nb, nt) * ux * vx * wx / 6.d0 + &
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tab (i1, nb, nt) * px * vx * wx / 2.d0 - &
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tab (i2, nb, nt) * px * ux * wx / 2.d0 + &
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tab (i3, nb, nt) * px * ux * vx / 6.d0
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endif
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enddo
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enddo
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enddo
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deallocate (q)
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allocate ( sk(npw) )
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ikb = 0
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do nt = 1, ntyp
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do na = 1, nat
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if (ityp (na) .eq.nt) then
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arg = (xk (1, ik) * tau (1, na) + xk (2, ik) * tau (2, na) &
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+ xk (3, ik) * tau (3, na) ) * tpi
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phase = CMPLX (cos (arg), - sin (arg) )
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do ig = 1, npw
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iig = igk (ig)
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sk (ig) = eigts1 (ig1 (iig), na) * eigts2 (ig2 (iig), na) &
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* eigts3 (ig3 (iig), na) * phase
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enddo
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do ih = 1, nh (nt)
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nb = indv (ih, nt)
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l = nhtol (ih, nt)
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lm = nhtolm(ih, nt)
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ikb = ikb + 1
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pref = (0.d0, -1.d0) **l
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!
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do ig = 1, npw
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dvkb (ig, ikb) = vkb0(ig, nb, nt) * sk(ig) * dylm_u(ig, lm) &
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* pref / tpiba
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enddo
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enddo
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endif
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enddo
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enddo
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if (ikb.ne.nkb) then
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WRITE( stdout, * ) ikb, nkb
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call errore ('gen_us_dy', 'unexpected error', 1)
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endif
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deallocate ( sk )
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deallocate ( vkb0, dylm_u, gk )
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return
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end subroutine gen_us_dy
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