mirror of https://gitlab.com/QEF/q-e.git
116 lines
3.3 KiB
Fortran
116 lines
3.3 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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!----------------------------------------------------------------------
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subroutine addusdbec (ik, wgt, psi, dbecsum)
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!----------------------------------------------------------------------
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!
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! This routine adds to dbecsum the contribution of this
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! k point. It implements Eq. B15 of PRB 64, 235118 (2001).
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!
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#include "f_defs.h"
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USE kinds, only : DP
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USE cell_base, ONLY : omega
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USE ions_base, ONLY : nat, ityp, ntyp => nsp
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USE becmod, ONLY : calbec
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USE wvfct, only: npw, npwx, nbnd
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USE uspp, only: nkb, vkb, okvan
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USE uspp_param, only: upf, nh, nhm
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USE phus, ONLY : becp1
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USE qpoint, ONLY : npwq, ikks
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USE control_ph, ONLY : nbnd_occ
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implicit none
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!
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! the dummy variables
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!
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complex(DP) :: dbecsum (nhm*(nhm+1)/2, nat), psi(npwx,nbnd)
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! inp/out: the sum kv of bec *
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! input : contains delta psi
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integer :: ik
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! input: the k point
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real(DP) :: wgt
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! input: the weight of this k point
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!
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! here the local variables
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!
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integer :: na, nt, ih, jh, ibnd, ikk, ikb, jkb, ijh, startb, &
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lastb, ijkb0
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! counter on atoms
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! counter on atomic type
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! counter on solid beta functions
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! counter on solid beta functions
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! counter on the bands
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! the real k point
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! counter on solid becp
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! counter on solid becp
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! composite index for dbecsum
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! divide among processors the sum
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! auxiliary variable for counting
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complex(DP), allocatable :: dbecq (:,:)
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! the change of becq
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if (.not.okvan) return
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call start_clock ('addusdbec')
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allocate (dbecq( nkb, nbnd))
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ikk = ikks(ik)
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!
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! First compute the product of psi and vkb
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!
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call calbec (npwq, vkb, psi, dbecq)
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!
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! And then we add the product to becsum
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!
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! Band parallelization: each processor takes care of its slice of bands
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!
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call divide (nbnd_occ (ikk), startb, lastb)
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!
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ijkb0 = 0
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do nt = 1, ntyp
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if (upf(nt)%tvanp ) then
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do na = 1, nat
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if (ityp (na) .eq.nt) then
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!
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! And qgmq and becp and dbecq
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!
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ijh = 1
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do ih = 1, nh (nt)
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ikb = ijkb0 + ih
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do ibnd = startb, lastb
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dbecsum (ijh, na) = dbecsum (ijh, na) + &
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wgt * ( CONJG(becp1(ikb,ibnd,ik)) * dbecq(ikb,ibnd) )
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enddo
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ijh = ijh + 1
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do jh = ih + 1, nh (nt)
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jkb = ijkb0 + jh
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do ibnd = startb, lastb
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dbecsum (ijh, na) = dbecsum (ijh, na) + &
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wgt*( CONJG(becp1(ikb,ibnd,ik)) * dbecq(jkb,ibnd) + &
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CONJG(becp1(jkb,ibnd,ik)) * dbecq(ikb,ibnd) )
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enddo
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ijh = ijh + 1
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enddo
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enddo
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ijkb0 = ijkb0 + nh (nt)
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endif
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enddo
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else
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do na = 1, nat
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if (ityp (na) .eq.nt) ijkb0 = ijkb0 + nh (nt)
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enddo
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endif
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enddo
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!
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deallocate (dbecq)
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call stop_clock ('addusdbec')
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return
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end subroutine addusdbec
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