mirror of https://gitlab.com/QEF/q-e.git
160 lines
4.5 KiB
Fortran
160 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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!----------------------------------------------------------------------
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subroutine gen_us_dj (ik, dvkb)
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!----------------------------------------------------------------------
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!
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! Calculates the beta function pseudopotentials with
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! the derivative of the Bessel functions
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!
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USE kinds, ONLY : DP
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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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complex(DP) :: dvkb (npwx, nkb)
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!
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! local variables
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!
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integer :: ikb, nb, ih, ig, i0, i1, i2, i3 , nt
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! counter on beta functions
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! counter on beta functions
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! counter on beta functions
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! counter on G vectors
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! index of the first nonzero point in the r
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! counter on atomic type
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real(DP) :: arg, px, ux, vx, wx
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! argument of the atomic phase factor
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complex(DP) :: phase, pref
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! atomic phase factor
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! prefactor
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integer :: na, l, iig, lm
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real(DP), allocatable :: djl (:,:,:), ylm (:,:), q (:), gk (:,:)
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real(DP) :: qt, eps
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parameter (eps = 1.0d-8)
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complex(DP), allocatable :: sk (:)
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integer :: iq
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real(DP), allocatable :: xdata(:)
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if (nkb.eq.0) return
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call start_clock('stres_us31')
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allocate (djl( npw , nbetam , ntyp))
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allocate (ylm( npw ,(lmaxkb + 1) **2))
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allocate (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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call stop_clock('stres_us31')
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call start_clock('stres_us32')
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call ylmr2 ((lmaxkb+1)**2, npw, gk, q, ylm)
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call stop_clock('stres_us32')
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call start_clock('stres_us33')
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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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do nb = 1, upf(nt)%nbeta
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do ig = 1, npw
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qt = sqrt(q (ig)) * tpiba
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if (spline_ps) then
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djl(ig,nb,nt) = splint_deriv(xdata, tab(:,nb,nt), &
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tab_d2y(:,nb,nt), qt)
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else
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px = qt / dq - int (qt / 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 = qt / 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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djl(ig,nb,nt) = ( tab (i0, nb, nt) * (-vx*wx-ux*wx-ux*vx)/6.d0 + &
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tab (i1, nb, nt) * (+vx*wx-px*wx-px*vx)/2.d0 - &
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tab (i2, nb, nt) * (+ux*wx-px*wx-px*ux)/2.d0 + &
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tab (i3, nb, nt) * (+ux*vx-px*vx-px*ux)/6.d0 )/dq
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endif
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enddo
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enddo
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enddo
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call stop_clock('stres_us33')
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call start_clock('stres_us34')
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deallocate (q)
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deallocate (gk)
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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) + &
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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) ,kind=DP)
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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) * &
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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) = djl (ig, nb, nt) * sk (ig) * ylm (ig, lm) &
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* pref
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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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call stop_clock('stres_us34')
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if (ikb.ne.nkb) call errore ('gen_us_dj', 'unexpected error', 1)
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deallocate (sk)
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deallocate (ylm)
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deallocate (djl)
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if (spline_ps) deallocate(xdata)
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return
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end subroutine gen_us_dj
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