mirror of https://gitlab.com/QEF/q-e.git
219 lines
7.6 KiB
Fortran
219 lines
7.6 KiB
Fortran
!
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! Copyright (C) 2001-2016 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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subroutine incdrhoscf_nc (drhoscf, weight, ik, dbecsum, dpsi, rsign)
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!-----------------------------------------------------------------------
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!
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! This routine computes the change of the charge density due to the
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! perturbation. It is called at the end of the computation of the
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! change of the wavefunction for a given k point.
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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 cell_base, ONLY : omega
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USE fft_base, ONLY : dffts, dfftp
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USE fft_interfaces, ONLY : invfft
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USE lsda_mod, ONLY : nspin
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USE noncollin_module, ONLY : npol, domag, nspin_mag
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USE uspp_param, ONLY : nhm
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USE wvfct, ONLY : npwx, nbnd
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USE wavefunctions, ONLY : evc
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USE klist, ONLY : ngk,igk_k
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USE qpoint, ONLY : ikks, ikqs
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USE control_lr, ONLY : nbnd_occ
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USE qpoint_aux, ONLY : becpt
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USE lrus, ONLY : becp1
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USE mp_bands, ONLY : me_bgrp, inter_bgrp_comm, ntask_groups
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USE mp, ONLY : mp_sum
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USE fft_helper_subroutines
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IMPLICIT NONE
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!
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! I/O variables
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INTEGER, INTENT(IN) :: ik
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! input: the k point
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REAL(DP), INTENT(IN) :: weight
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REAL(DP), INTENT(IN) :: rsign
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! input: the weight of the k point
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! the sign in front of the response of the magnetization density
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COMPLEX(DP), INTENT(IN) :: dpsi(npwx*npol,nbnd)
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! input: the perturbed wfcs at the given k point
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COMPLEX(DP), INTENT(INOUT) :: drhoscf (dfftp%nnr,nspin_mag), dbecsum (nhm,nhm,nat,nspin)
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! input/output: the accumulated change of the charge density and dbecsum
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!
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! here the local variable
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!
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REAL(DP) :: wgt
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! the effective weight of the k point
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!
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COMPLEX(DP), ALLOCATABLE :: psi (:,:), dpsic (:,:)
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! the wavefunctions in real space
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! the change of wavefunctions in real space
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!
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COMPLEX(DP), ALLOCATABLE :: tg_psi (:,:), tg_dpsi (:,:), tg_drho(:,:)
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!
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INTEGER :: npw, npwq, ikk, ikq
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INTEGER :: ibnd, jbnd, ir, ir3, ig, incr, v_siz, idx, ioff, ioff_tg, nxyp
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INTEGER :: ntgrp, right_inc
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! counters
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!
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!
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CALL start_clock ('incdrhoscf')
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!
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ALLOCATE (dpsic(dffts%nnr, npol))
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ALLOCATE (psi (dffts%nnr, npol))
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!
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wgt = 2.d0 * weight / omega
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ikk = ikks(ik)
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ikq = ikqs(ik)
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npw = ngk(ikk)
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npwq= ngk(ikq)
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incr = 1
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!
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IF (dffts%has_task_groups) THEN
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!
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v_siz = dffts%nnr_tg
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!
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ALLOCATE( tg_psi( v_siz, npol ) )
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ALLOCATE( tg_dpsi( v_siz, npol ) )
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ALLOCATE( tg_drho( v_siz, nspin_mag ) )
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!
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incr = fftx_ntgrp(dffts)
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!
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ENDIF
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!
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! dpsi contains the perturbed wavefunctions of this k point
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! evc contains the unperturbed wavefunctions of this k point
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!
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do ibnd = 1, nbnd_occ(ikk), incr
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IF (dffts%has_task_groups) THEN
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!
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tg_drho=(0.0_DP, 0.0_DP)
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tg_psi=(0.0_DP, 0.0_DP)
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tg_dpsi=(0.0_DP, 0.0_DP)
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!
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ioff = 0
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CALL tg_get_recip_inc( dffts, right_inc )
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ntgrp = fftx_ntgrp( dffts )
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!
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DO idx = 1, ntgrp
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!
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! ... dtgs%nogrp ffts at the same time. We prepare both
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! evc (at k) and dpsi (at k+q)
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!
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IF( idx + ibnd - 1 <= nbnd_occ(ikk) ) THEN
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!
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DO ig = 1, npw
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tg_psi( dffts%nl( igk_k( ig,ikk ) ) + ioff, 1 ) = evc( ig, idx+ibnd-1 )
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tg_psi( dffts%nl( igk_k( ig,ikk ) ) + ioff, 2 ) = evc( npwx+ig, idx+ibnd-1 )
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END DO
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DO ig = 1, npwq
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tg_dpsi( dffts%nl( igk_k( ig,ikq ) ) + ioff, 1 ) = dpsi( ig, idx+ibnd-1 )
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tg_dpsi( dffts%nl( igk_k( ig,ikq ) ) + ioff, 2 ) = dpsi( npwx+ig, idx+ibnd-1 )
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END DO
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!
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END IF
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!
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ioff = ioff + right_inc
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!
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END DO
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CALL invfft ('tgWave', tg_psi(:,1), dffts)
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CALL invfft ('tgWave', tg_psi(:,2), dffts)
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CALL invfft ('tgWave', tg_dpsi(:,1), dffts)
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CALL invfft ('tgWave', tg_dpsi(:,2), dffts)
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do ir = 1, dffts%nr1x * dffts%nr2x * dffts%my_nr3p
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tg_drho (ir,1) = tg_drho (ir,1) + wgt * (CONJG(tg_psi (ir,1) )*tg_dpsi (ir,1) &
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+ CONJG(tg_psi (ir,2) )*tg_dpsi (ir,2) )
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enddo
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IF (domag) THEN
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do ir = 1, dffts%nr1x * dffts%nr2x * dffts%my_nr3p
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tg_drho(ir,2)= tg_drho(ir,2) + (rsign) *wgt * (CONJG(tg_psi(ir,1))*tg_dpsi(ir,2) &
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+ CONJG(tg_psi(ir,2))*tg_dpsi(ir,1) )
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tg_drho(ir,3)= tg_drho(ir,3) + (rsign) *wgt * (CONJG(tg_psi(ir,1))*tg_dpsi(ir,2) &
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- CONJG(tg_psi(ir,2))*tg_dpsi(ir,1) ) * (0.d0,-1.d0)
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tg_drho(ir,4)= tg_drho(ir,4) + (rsign) *wgt * (CONJG(tg_psi(ir,1))*tg_dpsi(ir,1) &
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- CONJG(tg_psi(ir,2))*tg_dpsi(ir,2) )
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enddo
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ENDIF
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!
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! reduce the group charge (equivalent to sum over the bands of the
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! orbital group)
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!
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CALL tg_reduce_rho( drhoscf, tg_drho, dffts )
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!
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ELSE
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!
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! Normal case: no task groups
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!
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! FFT to R-space of the unperturbed wfct's evc
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!
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psi = (0.d0, 0.d0)
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do ig = 1, npw
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psi (dffts%nl (igk_k(ig,ikk) ), 1) = evc (ig, ibnd)
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psi (dffts%nl (igk_k(ig,ikk) ), 2) = evc (ig+npwx, ibnd)
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enddo
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CALL invfft ('Wave', psi(:,1), dffts)
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CALL invfft ('Wave', psi(:,2), dffts)
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!
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! FFT to R-space of the perturbed wfct's dpsi
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!
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dpsic = (0.d0, 0.d0)
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do ig = 1, npwq
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dpsic (dffts%nl (igk_k(ig,ikq)), 1 ) = dpsi (ig, ibnd)
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dpsic (dffts%nl (igk_k(ig,ikq)), 2 ) = dpsi (ig+npwx, ibnd)
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enddo
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CALL invfft ('Wave', dpsic(:,1), dffts)
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CALL invfft ('Wave', dpsic(:,2), dffts)
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!
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! Calculation of the response charge density
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!
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do ir = 1, dffts%nnr
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drhoscf(ir,1)=drhoscf(ir,1)+wgt*(CONJG(psi(ir,1))*dpsic(ir,1) + &
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CONJG(psi(ir,2))*dpsic(ir,2) )
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enddo
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IF (domag) THEN
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do ir = 1, dffts%nnr
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drhoscf(ir,2)=drhoscf (ir,2) + (rsign) *wgt * (CONJG(psi(ir,1))*dpsic(ir,2) &
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+ CONJG(psi(ir,2))*dpsic(ir,1) )
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drhoscf(ir,3)=drhoscf (ir,3) + (rsign) *wgt * (CONJG(psi(ir,1))*dpsic(ir,2) &
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- CONJG(psi(ir,2))*dpsic(ir,1) ) * (0.d0,-1.d0)
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drhoscf(ir,4)=drhoscf (ir,4) + (rsign) *wgt * (CONJG(psi(ir,1))*dpsic(ir,1) &
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- CONJG(psi(ir,2))*dpsic(ir,2) )
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enddo
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END IF
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!
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END IF
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!
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enddo
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!
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! Ultrasoft contribution
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! Calculate dbecsum_nc = <evc|vkb><vkb|dpsi>
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!
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IF (rsign==1.0d0) THEN
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CALL addusdbec_nc (ik, weight, dpsi, dbecsum, becp1)
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ELSE
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CALL addusdbec_nc (ik, weight, dpsi, dbecsum, becpt)
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ENDIF
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!
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DEALLOCATE(psi)
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DEALLOCATE(dpsic)
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!
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IF (dffts%has_task_groups) THEN
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DEALLOCATE(tg_psi)
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DEALLOCATE(tg_dpsi)
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DEALLOCATE(tg_drho)
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END IF
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!
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CALL stop_clock ('incdrhoscf')
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!
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RETURN
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!
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end subroutine incdrhoscf_nc
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