2003-01-20 05:58:50 +08:00
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!
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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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2003-02-08 00:04:36 +08:00
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subroutine compute_becalp (becq, alpq)
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2003-01-20 05:58:50 +08:00
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!---------------------------------------------------------------------
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!
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! This routine is used only if .not.lgamma and in this case
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! computes the scalar product of vkb and psi_{k+q}
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!
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#include "machine.h"
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2003-02-08 00:04:36 +08:00
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use pwcom
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use parameters, only : DP
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use phcom
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implicit none
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2003-01-20 05:58:50 +08:00
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complex(kind=DP) :: becq(nkb, nbnd, nksq), alpq(nkb,nbnd,3,nksq)
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! the becp with psi_{k+q}
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! the alphap with psi_{k+q}
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2003-02-08 00:04:36 +08:00
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integer :: ik, ikq, ipol, ibnd, ig, ios
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2003-01-20 05:58:50 +08:00
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! counter on k points
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! counter on polarizations, bands and
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! used for i/o control
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complex(kind=DP) :: fact
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2003-02-08 00:04:36 +08:00
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complex(kind=DP), allocatable :: aux (:,:)
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2003-01-20 05:58:50 +08:00
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!
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2003-02-08 00:04:36 +08:00
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if (lgamma) return
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2003-01-20 05:58:50 +08:00
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2003-02-08 00:04:36 +08:00
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allocate (aux ( npwx , nbnd))
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if (nksq.gt.1) rewind (iunigk)
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do ik = 1, nksq
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2003-01-20 05:58:50 +08:00
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2003-02-08 00:04:36 +08:00
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ikq = 2 * ik
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if (nksq.gt.1) then
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read (iunigk, err = 100, iostat = ios) npw, igk
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2003-01-20 05:58:50 +08:00
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2003-02-08 00:04:36 +08:00
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100 call error ('compute_becalp', 'reading igk', abs (ios) )
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read (iunigk, err = 200, iostat = ios) npwq, igkq
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200 call error ('compute_becalp', 'reading igkq', abs (ios) )
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2003-01-20 05:58:50 +08:00
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endif
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2003-02-08 00:04:36 +08:00
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call init_us_2 (npwq, igkq, xk (1, ikq), vkb)
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call davcio (evq, lrwfc, iuwfc, ikq, - 1)
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2003-01-20 05:58:50 +08:00
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call ccalbec (nkb, npwx, npwq, nbnd, becq (1, 1, ik), vkb, evq)
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2003-02-08 00:04:36 +08:00
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do ipol = 1, 3
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do ibnd = 1, nbnd
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do ig = 1, npwq
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2003-01-20 05:58:50 +08:00
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aux (ig, ibnd) = evq (ig, ibnd) * &
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(xk (ipol, ikq) + g (ipol, igkq(ig) ) )
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enddo
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enddo
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call ccalbec (nkb, npwx, npwq, nbnd, alpq(1, 1, ipol, ik),vkb, aux)
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enddo
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enddo
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2003-02-08 00:04:36 +08:00
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fact = DCMPLX (0.d0, tpiba)
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2003-01-20 05:58:50 +08:00
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2003-02-08 00:04:36 +08:00
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call ZSCAL (nkb * nbnd * 3 * nksq, fact, alpq, 1)
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deallocate (aux)
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return
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2003-01-20 05:58:50 +08:00
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end subroutine compute_becalp
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