mirror of https://gitlab.com/QEF/q-e.git
227 lines
7.3 KiB
Fortran
227 lines
7.3 KiB
Fortran
!
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! Copyright (C) 2001-2018 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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SUBROUTINE cft_wave (ik, evc_g, evc_r, isw)
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!-----------------------------------------------------------------------
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!
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! Inverse Fourier (isw=+1) or Fourier (isw=-1) transform of a wavefunction
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! Typical usage: compute product Vpsi = (Vq*psi)(k+q+G)
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! where Vq = perturbation of wave-vector q . Example:
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! cft_wave (ik, psi, aux,+1) psi in G space, psi(i) =\psi(k+G_i)
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! compute aux(r)= Vq(r)*aux(r) Vq in R-space, Vq(i) =V(r_i)
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! cft_wave (ik, vpsi, aux,-1) Vpsi in G-space,Vpsi(i)=Vpsi(k+q+G_i)
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!
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! Input/Output variables:
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! ik: index of k-point under consideration
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! evc_g(npwx*npol): wavefunction in G space, ordering: see below
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! evc_r(dffts%nnr,npol): wavefunction in R space, ordering: same as
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! real-space points on the "smooth" FFT grid
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!
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! isw =+1 input: evc_g (ordered as \psi(k+G), using k+G indices)
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! output: evc_r = Fourier(evc_g), evc_g = unchanged
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! isw =-1 input: evc_r (overwritten on output)
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! output: evc_g = evc_g + InvFourier(evc_r)
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! ordered as \psi(k+q+G), using k+q+G indices
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!
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! ikks(ik) and ikqs(ik) must point in array igk_k(:,i) to the list of k+G
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! vectors (i=ikks(ik)) and to k+q+G indices (i=ikqs(ik)), respectively
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!
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USE kinds, ONLY : DP
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USE wvfct, ONLY : npwx
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USE qpoint, ONLY : ikks, ikqs
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USE klist, ONLY : ngk, igk_k
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USE fft_base, ONLY : dffts
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USE noncollin_module, ONLY : npol
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IMPLICIT NONE
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INTEGER, INTENT(IN) :: ik, isw
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COMPLEX(DP) :: evc_g (npwx*npol), evc_r (dffts%nnr,npol)
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! intent depends upon the value of isw
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!
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INTEGER :: ig, ikk, ikq, npw, npwq
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CALL start_clock ('cft_wave')
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IF (isw == 1) THEN
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ikk = ikks(ik) ! points to k+G indices
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npw = ngk(ikk)
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CALL invfft_wave (npw, igk_k (1,ikk), evc_g, evc_r )
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ELSE IF (isw == -1) then
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ikq = ikqs(ik) ! points to k+q+G indices
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npwq= ngk(ikq)
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CALL fwfft_wave (npwq, igk_k (1,ikq), evc_g, evc_r )
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ELSE
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CALL errore ('cft_wave',' Wrong value for isw',1)
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ENDIF
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CALL stop_clock ('cft_wave')
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RETURN
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END SUBROUTINE cft_wave
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SUBROUTINE fwfft_wave (npwq, igkq, evc_g, evc_r )
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USE kinds, ONLY : DP
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USE wvfct, ONLY : npwx
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USE fft_base, ONLY : dffts
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USE fft_interfaces, ONLY: fwfft
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USE noncollin_module, ONLY : noncolin, npol
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IMPLICIT NONE
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INTEGER, INTENT(IN) :: npwq, igkq(npwq)
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COMPLEX(DP), INTENT(INOUT) :: evc_g (npwx*npol), evc_r (dffts%nnr,npol)
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!
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INTEGER :: ig
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CALL fwfft ('Wave', evc_r(:,1), dffts)
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DO ig = 1, npwq
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evc_g (ig) = evc_g (ig) + evc_r (dffts%nl (igkq(ig) ), 1 )
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ENDDO
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IF (noncolin) THEN
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CALL fwfft ('Wave', evc_r(:,2), dffts)
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DO ig = 1, npwq
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evc_g (ig+npwx) = evc_g (ig+npwx) + evc_r (dffts%nl(igkq(ig)),2)
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ENDDO
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ENDIF
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END SUBROUTINE fwfft_wave
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SUBROUTINE invfft_wave (npw, igk, evc_g, evc_r )
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USE kinds, ONLY : DP
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USE wvfct, ONLY : npwx
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USE fft_base, ONLY : dffts
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USE fft_interfaces, ONLY: invfft
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USE noncollin_module, ONLY : noncolin, npol
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IMPLICIT NONE
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INTEGER, INTENT(IN) :: npw, igk(npw)
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COMPLEX(DP), INTENT(IN) :: evc_g (npwx*npol)
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COMPLEX(DP), INTENT(OUT):: evc_r (dffts%nnr,npol)
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!
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INTEGER :: ig
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evc_r = (0.0_dp, 0.0_dp)
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DO ig = 1, npw
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evc_r (dffts%nl (igk(ig) ),1 ) = evc_g (ig)
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ENDDO
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CALL invfft ('Wave', evc_r(:,1), dffts)
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IF (noncolin) THEN
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DO ig = 1, npw
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evc_r (dffts%nl(igk(ig)),2) = evc_g (ig+npwx)
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ENDDO
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CALL invfft ('Wave', evc_r(:,2), dffts)
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ENDIF
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END SUBROUTINE invfft_wave
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!
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!-----------------------------------------------------------------------
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SUBROUTINE cft_wave_tg (ik, evc_g, evc_r, isw, v_size, ibnd, nbnd_occ)
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!-----------------------------------------------------------------------
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!
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! Inverse Fourier (isw=+1) or Fourier (isw=-1) transform of a wavefunction
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! using task group parallelization
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!
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! ik: index of k-point under consideration
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! evc_g(npwx*npol,nbnd_occ): wavefunction in G space, ordering: see below
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! evc_r(v_size,npol): wavefunction in R space, ordering: same as
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! real-space points on the "smooth" FFT grid
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! isw =+1 input: evc_g (ordered as \psi(k+G), using k+G indices)
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! output: evc_r = Fourier(evc_g), evc_g = unchanged
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! isw =-1 input: evc_r (overwritten on output)
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! output: evc_g = evc_g + InvFourier(evc_r)
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! ordered as \psi(k+q+G), using k+q+G indices
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! v_size: dimension of FFT arrays in real space using task groups
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! ibnd : index of first band in the current task group
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! nbnd_occ: number of occupied states
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!
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! Further required variables from modules (must be properly initialized,
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! unchanged on output):
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!
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USE kinds, ONLY : DP
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USE wvfct, ONLY : npwx
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USE fft_base, ONLY : dffts
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USE qpoint, ONLY : ikks, ikqs
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USE klist, ONLY : ngk, igk_k
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USE mp_bands, ONLY : me_bgrp
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USE fft_interfaces, ONLY: fwfft, invfft
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USE noncollin_module, ONLY : noncolin, npol
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USE fft_helper_subroutines
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IMPLICIT NONE
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INTEGER, INTENT(in) :: ik, v_size, isw, ibnd, nbnd_occ
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COMPLEX(DP), INTENT(inout) :: evc_g(npwx*npol,nbnd_occ), evc_r(v_size,npol)
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INTEGER :: ig, ikk, ikq, ioff, idx, npw, npwq, ntgrp, right_inc
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CALL start_clock ('cft_wave_tg')
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ntgrp = fftx_ntgrp( dffts )
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CALL tg_get_recip_inc( dffts, right_inc )
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IF (isw == 1) then
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ikk = ikks(ik) ! points to k+G indices
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npw = ngk(ikk)
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evc_r = (0.0_dp, 0.0_dp)
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!
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ioff = 0
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DO idx = 1, ntgrp
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!
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IF( idx + ibnd - 1 <= nbnd_occ ) THEN
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DO ig = 1, npw
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evc_r(dffts%nl (igk_k(ig,ikk))+ioff,1) = evc_g(ig,idx+ibnd-1)
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ENDDO
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IF (noncolin) THEN
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DO ig = 1, npw
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evc_r(dffts%nl (igk_k(ig,ikk))+ioff,2) = evc_g(npwx+ig,idx+ibnd-1)
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ENDDO
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ENDIF
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ENDIF
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!
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ioff = ioff + right_inc
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!
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ENDDO
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CALL invfft ('tgWave', evc_r(:,1), dffts)
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IF (noncolin) CALL invfft ('tgWave', evc_r(:,2), dffts)
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ELSE IF(isw == -1) THEN
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ikq = ikqs(ik) ! points to k+q+G indices
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npwq= ngk(ikq)
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CALL fwfft ('tgWave', evc_r(:,1), dffts)
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IF (noncolin) CALL fwfft ('tgWave', evc_r(:,2), dffts)
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!
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ioff = 0
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DO idx = 1, ntgrp
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!
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IF( idx + ibnd - 1 <= nbnd_occ ) THEN
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!
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DO ig = 1, npwq
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evc_g(ig, ibnd+idx-1) = evc_g(ig, ibnd+idx-1) + &
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evc_r( dffts%nl(igk_k(ig,ikq)) + ioff, 1 )
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ENDDO
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!
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IF (noncolin) THEN
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DO ig = 1, npwq
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evc_g (ig+npwx, ibnd+idx-1) = evc_g (ig+npwx, ibnd+idx-1) &
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+ evc_r (dffts%nl(igk_k(ig,ikq))+ ioff,2)
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ENDDO
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ENDIF
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!
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ENDIF
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!
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ioff = ioff + right_inc
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!
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ENDDO
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ELSE
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CALL errore ('cft_wave_tg',' Wrong value for isw',1)
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ENDIF
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CALL stop_clock ('cft_wave_tg')
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RETURN
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END SUBROUTINE cft_wave_tg
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