mirror of https://gitlab.com/QEF/q-e.git
126 lines
3.4 KiB
Fortran
126 lines
3.4 KiB
Fortran
!
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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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subroutine drhodv (nu_i0, nper, drhoscf)
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!-----------------------------------------------------------------------
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!
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! This subroutine computes the electronic term
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! <psi|dv|dpsi> of the dynamical matrix
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!
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#include "f_defs.h"
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!
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USE ions_base, ONLY : nat
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use pwcom
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USE kinds, only : DP
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USE io_files, ONLY: iunigk
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use phcom
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implicit none
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integer :: nper, nu_i0
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! input: number of perturbations of this represent
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! input: the initial position of the mode
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complex(DP) :: drhoscf (nrxx, nspin, npertx)
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! the change of density due to perturbations
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integer :: mu, ik, ikq, ig, nu_i, nu_j, na_jcart, ibnd, nrec, &
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ipol, ikk
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! counters
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! ikk: record position for wfc at k
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complex(DP) :: fact, ps, dynwrk (3 * nat, 3 * nat), &
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wdyn (3 * nat, 3 * nat), ZDOTC
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complex(DP), allocatable :: aux (:,:), dbecq (:,:,:), &
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dalpq (:,:,:,:)
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! work space
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!
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! Initialize the auxiliary matrix wdyn
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!
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call start_clock ('drhodv')
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allocate (dbecq ( nkb , nbnd, nper))
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allocate (dalpq ( nkb , nbnd ,3 ,nper))
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allocate (aux ( npwx , nbnd))
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dynwrk(:,:) = (0.d0, 0.d0)
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wdyn (:,:) = (0.d0, 0.d0)
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!
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! We need a sum over all k points ...
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!
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if (nksq > 1) rewind (unit = iunigk)
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do ik = 1, nksq
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if (nksq > 1) read (iunigk) npw, igk
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if (lgamma) then
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ikk = ik
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ikq = ik
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npwq = npw
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else
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ikk = 2 * ik - 1
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ikq = ikk + 1
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if (nksq > 1) read (iunigk) npwq, igkq
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endif
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if (lsda) current_spin = isk (ikk)
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call init_us_2 (npwq, igkq, xk (1, ikq), vkb)
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do mu = 1, nper
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nrec = (mu - 1) * nksq + ik
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if (nksq > 1 .or. nper > 1) call davcio(dpsi, lrdwf, iudwf, nrec,-1)
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call ccalbec (nkb, npwx, npwq, nbnd, dbecq (1, 1, mu), vkb, dpsi)
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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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aux (ig, ibnd) = dpsi (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, dalpq(1,1,ipol,mu), vkb, aux)
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enddo
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enddo
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fact = CMPLX (0.d0, tpiba)
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dalpq = dalpq * fact
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call drhodvnl (ik, ikk, nper, nu_i0, dynwrk, dbecq, dalpq)
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enddo
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!
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! put in the basis of the modes
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!
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do nu_i = 1, 3 * nat
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do nu_j = 1, 3 * nat
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ps = (0.0d0, 0.0d0)
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do na_jcart = 1, 3 * nat
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ps = ps + dynwrk (nu_i, na_jcart) * u (na_jcart, nu_j)
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enddo
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wdyn (nu_i, nu_j) = wdyn (nu_i, nu_j) + ps
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enddo
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enddo
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#ifdef __PARA
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!
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! collect contributions from all pools (sum over k-points)
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!
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call poolreduce (18 * nat * nat, wdyn)
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#endif
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!
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! add the contribution of the local part of the perturbation
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!
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call drhodvloc (nu_i0, nper, drhoscf, wdyn)
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!
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! add to the rest of the dynamical matrix
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!
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! WRITE( stdout,*) 'drhodv dyn, wdyn'
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! call tra_write_matrix('drhodv dyn',dyn,u,nat)
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! call tra_write_matrix('drhodv wdyn',wdyn,u,nat)
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dyn (:,:) = dyn (:,:) + wdyn (:,:)
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deallocate (aux)
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deallocate (dalpq)
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deallocate (dbecq)
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call stop_clock ('drhodv')
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return
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end subroutine drhodv
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