mirror of https://gitlab.com/QEF/q-e.git
136 lines
3.9 KiB
Fortran
136 lines
3.9 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 compute_drhous_nc (drhous, dbecsum, wgg, becq, alpq)
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!-----------------------------------------------------------------------
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!
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! This routine computes the part of the change of the charge density
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! which is due to the orthogonalization constraint on wavefunctions
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!
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!
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!
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USE kinds, ONLY : DP
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USE ions_base, ONLY : nat
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USE lsda_mod, ONLY : lsda, nspin, current_spin, isk
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USE klist, ONLY : xk, wk
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USE fft_base, ONLY : dffts, dfftp
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USE fft_interfaces, ONLY : invfft
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USE gvecs, ONLY : nls
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USE wvfct, ONLY : npw, npwx, nbnd, igk
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USE noncollin_module, ONLY : noncolin, npol, nspin_mag
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USE wavefunctions_module, ONLY: evc
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USE io_files, ONLY: iunigk
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USE uspp, ONLY: okvan, nkb, vkb
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USE uspp_param, ONLY: nhm
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USE qpoint, ONLY : nksq, igkq, npwq, ikks, ikqs
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USE eqv, ONLY : evq
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USE units_ph, ONLY : lrwfc, iuwfc
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USE control_ph, ONLY : lgamma
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USE becmod, ONLY : bec_type
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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, nat, nspin, 3 * nat), &
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drhous (dfftp%nnr, nspin_mag, 3 * nat)
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!output:the derivative of becsum
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! output: add the orthogonality term
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type (bec_type) :: becq(nksq), & ! (nkb, nbnd)
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alpq (3, nksq)
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! input: the becp with psi_{k+q}
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! input: the alphap with psi_{k+q}
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real(DP) :: wgg (nbnd, nbnd, nksq)
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! input: the weights
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integer :: ipert, mode, ik, ikq, ikk, is, ig, nu_i, ibnd, ios
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! counter on the pertubations
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! counter on the modes
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! counter on k points
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! the point k+q
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! record for wfcs at k point
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! counter on spin
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! counter on g vectors
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! counter on modes
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! counter on the bands
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! integer variable for I/O control
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real(DP) :: weight
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! the weight of the k point
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complex(DP), allocatable :: evcr (:,:,:)
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! the wavefunctions in real space
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if (.not.okvan) return
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call start_clock ('com_drhous')
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allocate (evcr( dffts%nnr, npol, nbnd))
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!
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drhous(:,:,:) = (0.d0, 0.d0)
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dbecsum = (0.d0, 0.d0)
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if (nksq.gt.1) rewind (unit = iunigk)
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do ik = 1, nksq
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if (nksq.gt.1) then
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read (iunigk, err = 110, iostat = ios) npw, igk
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110 call errore ('compute_drhous', 'reading igk', abs (ios) )
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endif
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if (lgamma) npwq = npw
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ikk = ikks(ik)
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ikq = ikqs(ik)
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weight = wk (ikk)
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if (lsda) current_spin = isk (ikk)
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if (.not.lgamma.and.nksq.gt.1) then
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read (iunigk, err = 210, iostat = ios) npwq, igkq
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210 call errore ('compute_drhous', 'reading igkq', abs (ios) )
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endif
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!
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! For each k point we construct the beta functions
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!
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call init_us_2 (npwq, igkq, xk (1, ikq), vkb)
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!
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! Read the wavefunctions at k and transform to real space
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!
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call davcio (evc, lrwfc, iuwfc, ikk, - 1)
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evcr = (0.d0, 0.d0)
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do ibnd = 1, nbnd
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do ig = 1, npw
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evcr (nls (igk (ig) ), 1, ibnd) = evc (ig, ibnd)
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evcr (nls (igk (ig) ), 2, ibnd) = evc (ig+npwx, ibnd)
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enddo
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CALL invfft ('Wave', evcr (:, 1, ibnd), dffts)
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CALL invfft ('Wave', evcr (:, 2, ibnd), dffts)
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enddo
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!
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! Read the wavefunctions at k+q
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!
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if (.not.lgamma.and.nksq.gt.1) call davcio (evq, lrwfc, iuwfc, ikq, -1)
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!
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! And compute the contribution of this k point to the change of
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! the charge density
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!
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do nu_i = 1, 3 * nat
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call incdrhous_nc (drhous (1, 1, nu_i), weight, ik, &
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dbecsum (1, 1, 1, 1, nu_i), evcr, wgg, becq, alpq, nu_i)
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enddo
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enddo
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deallocate(evcr)
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call stop_clock ('com_drhous')
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return
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end subroutine compute_drhous_nc
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