mirror of https://gitlab.com/QEF/q-e.git
233 lines
7.8 KiB
Fortran
233 lines
7.8 KiB
Fortran
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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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!----------------------------------------------------------------------
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subroutine dqrhod2v (ipert, drhoscf)
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!-----------------------------------------------------------------------
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! calculates the term containing the second variation of the potential
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! and the first variation of the charge density with respect to a
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! perturbation at a generic q
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!
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#include "machine.h"
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use pwcom
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use phcom
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use d3com
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use allocate
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#ifdef PARA
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use para
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#endif
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implicit none
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integer :: ipert
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complex (8) :: drhoscf (nrxx)
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! the variation of the charge density
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!
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! local variables
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!
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integer :: icart, jcart, na_icart, na_jcart, na, ng, nt, &
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ik, ikk, ikq, ig, ibnd, nu_i, nu_j, nu_k, ikb, jkb, nrec, ios
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! index of the perturbation associated with drho
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! counter on polarizations
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! counter on polarizations
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! counter on modes
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! counter on modes
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! counter on atoms
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! counter on G vectors
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! counter on atomic types
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! counter on k points
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! counter on k points
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! counter on k+q points
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! counter on G vectors
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! counter on bands
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! counter on modes
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! counter on modes
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! counter on modes
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! counters on beta functions
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! record position of dwfc
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! integer variable for I/O control
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real (8) :: gtau, wgg
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! the product G*\tau_s
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! the weight of a K point
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complex (8) :: ZDOTC, fac, alpha (8), work
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complex (8), pointer :: d3dywrk (:,:), work0 (:), &
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work1 (:), work2 (:), work3 (:), work4 (:), work5 (:), work6 (:)
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! work space
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call mallocate (d3dywrk, 3 * nat, 3 * nat)
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call mallocate (work0, nrxx)
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call mallocate (work1, npwx)
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call mallocate (work2, npwx)
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call mallocate (work3, npwx)
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call mallocate (work4, npwx)
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call mallocate (work5, npwx)
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call mallocate (work6, npwx)
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call setv (2 * 9 * nat * nat, 0.0d0, d3dywrk, 1)
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!
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! Here the contribution deriving from the local part of the potential
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#ifdef PARA
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! ... computed only by the first pool (no sum over k needed)
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!
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if (mypool.ne.1) goto 100
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#endif
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!
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call ZCOPY (nrxx, drhoscf, 1, work0, 1)
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call cft3 (work0, nr1, nr2, nr3, nrx1, nrx2, nrx3, - 1)
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do na = 1, nat
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do icart = 1, 3
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na_icart = 3 * (na - 1) + icart
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do jcart = 1, 3
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na_jcart = 3 * (na - 1) + jcart
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do ng = 1, ngm
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gtau = tpi * ( (xq (1) + g (1, ng) ) * tau (1, na) + &
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(xq (2) + g (2, ng) ) * tau (2, na) + &
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(xq (3) + g (3, ng) ) * tau (3, na) )
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fac = DCMPLX (cos (gtau), - sin (gtau) )
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d3dywrk (na_icart, na_jcart) = d3dywrk (na_icart, na_jcart) &
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- tpiba2 * omega * (xq (icart) + g (icart, ng) ) * &
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(xq (jcart) + g (jcart, ng) ) * &
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vlocq (ng, ityp (na) ) * fac * conjg (work0 (nl (ng) ) )
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enddo
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enddo
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enddo
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enddo
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#ifdef PARA
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call reduce (2 * 9 * nat * nat, d3dywrk)
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!
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! each pool contributes to next term
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!
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100 continue
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#endif
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!
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! Here we compute the nonlocal (Kleinman-Bylander) contribution.
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!
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rewind (unit = iunigk)
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do ik = 1, nksq
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read (iunigk, err = 200, iostat = ios) npw, igk
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200 call error ('dqrhod2v', 'reading igk', abs (ios) )
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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 = 2 * ik
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read (iunigk, err = 300, iostat = ios) npwq, igkq
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300 call error ('dqrhod2v', 'reading igkq', abs (ios) )
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endif
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wgg = wk (ikk)
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call davcio (evc, lrwfc, iuwfc, ikk, - 1)
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!
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! In metallic case it necessary to know the wave function at k+q point
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! so as to correct dpsi. dvpsi is used as working array
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!
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if (degauss.ne.0.d0) call davcio (dvpsi, lrwfc, iuwfc, ikq, -1)
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call init_us_2 (npwq, igkq, xk (1, ikq), vkb)
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call init_us_2 (npw, igk, xk (1, ikk), vkb0)
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!
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! Reads the first variation of the wavefunction projected on conduction
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!
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nrec = (ipert - 1) * nksq + ik
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call davcio (dpsi, lrdwf, iudqwf, nrec, - 1)
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!
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! In the metallic case corrects dpsi so as that the density matrix
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! will be: Sum_{k,nu} 2 * | dpsi > < psi |
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!
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if (degauss.ne.0.d0) then
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nrec = ipert + (ik - 1) * 3 * nat
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call davcio (psidqvpsi, lrpdqvp, iupdqvp, nrec, - 1)
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call dpsi_corr (dvpsi, psidqvpsi, ikk, ikq, ipert)
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endif
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!
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do icart = 1, 3
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do jcart = 1, 3
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do ibnd = 1, nbnd
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do ig = 1, npw
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work1(ig)=evc(ig,ibnd)*tpiba*(xk(icart,ikk)+g(icart,igk(ig)))
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work2(ig)=evc(ig,ibnd)*tpiba*(xk(jcart,ikk)+g(jcart,igk(ig)))
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work5(ig)= work1(ig)*tpiba*(xk(jcart,ikk)+g(jcart,igk(ig)))
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enddo
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do ig = 1, npwq
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work3(ig)=dpsi(ig,ibnd)*tpiba*(xk(icart,ikq)+g(icart,igkq(ig)))
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work4(ig)=dpsi(ig,ibnd)*tpiba*(xk(jcart,ikq)+g(jcart,igkq(ig)))
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work6(ig)= work3(ig)*tpiba*(xk(jcart,ikq)+g(jcart,igkq(ig)))
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enddo
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jkb=0
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do nt = 1, ntyp
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do na = 1, nat
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if (ityp (na).eq.nt) then
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na_icart = 3 * (na - 1) + icart
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na_jcart = 3 * (na - 1) + jcart
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do ikb = 1, nh (nt)
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jkb = jkb+1
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alpha(1) = ZDOTC(npw, work1, 1,vkb0(1,jkb), 1)
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alpha(2) = ZDOTC(npwq,vkb(1,jkb), 1, work4, 1)
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alpha(3) = ZDOTC(npw, work2, 1,vkb0(1,jkb), 1)
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alpha(4) = ZDOTC(npwq,vkb(1,jkb), 1, work3, 1)
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alpha(5) = ZDOTC(npw, work5, 1,vkb0(1,jkb), 1)
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alpha(6) = ZDOTC(npwq,vkb(1,jkb),1,dpsi(1,ibnd),1)
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alpha(7) = ZDOTC(npw, evc(1,ibnd),1,vkb0(1,jkb),1)
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alpha(8) = ZDOTC(npwq,vkb(1,jkb),1,work6, 1)
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#ifdef PARA
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call reduce(16, alpha)
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#endif
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d3dywrk(na_icart,na_jcart) = d3dywrk(na_icart,na_jcart) &
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+ conjg(alpha(1) * alpha(2) + alpha(3) * alpha(4) - &
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alpha(5) * alpha(6) - alpha(7) * alpha(8) ) &
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* dvan (ikb, ikb, nt) * wgg * 2.0d0
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enddo
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endif
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enddo
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end do
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end do
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enddo
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enddo
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enddo
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#ifdef PARA
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call poolreduce (2 * 9 * nat * nat, d3dywrk)
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#endif
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!
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! Rotate the dynamical matrix on the basis of patterns
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! some indices do not need to be rotated
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!
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nu_k = ipert
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do nu_i = 1, 3 * nat
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if (q0mode (nu_i) ) then
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do nu_j = 1, 3 * nat
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work = (0.0d0, 0.0d0)
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do na = 1, nat
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do icart = 1, 3
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na_icart = 3 * (na - 1) + icart
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do jcart = 1, 3
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na_jcart = 3 * (na - 1) + jcart
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work = work + ug0 (na_icart, nu_i) * &
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d3dywrk (na_icart,na_jcart) * u (na_jcart, nu_j)
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enddo
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enddo
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enddo
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d3dyn (nu_i, nu_k, nu_j) = d3dyn (nu_i, nu_k, nu_j) + work
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d3dyn (nu_i, nu_j, nu_k) = d3dyn (nu_i, nu_j, nu_k) + conjg(work)
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enddo
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endif
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enddo
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call mfree (work6)
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call mfree (work5)
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call mfree (work4)
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call mfree (work3)
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call mfree (work2)
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call mfree (work1)
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call mfree (work0)
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call mfree (d3dywrk)
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return
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end subroutine dqrhod2v
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