mirror of https://gitlab.com/QEF/q-e.git
152 lines
4.3 KiB
Fortran
152 lines
4.3 KiB
Fortran
!
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! Copyright (C) 2003-2007 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 dvpsi_e(kpoint,ipol)
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!----------------------------------------------------------------------
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!
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! Calculates x * psi_k for each k-points and for the 3 polarizations
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! Requires on input: vkb, evc, igk
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!
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USE ions_base, ONLY : ntyp => nsp, nat, ityp
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USE kinds, ONLY: DP
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USE pwcom
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USE uspp, ONLY: nkb, vkb, dvan
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USE uspp_param, ONLY: nh
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USE wavefunctions_module, ONLY: evc
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USE becmod, ONLY: bec_type, becp, calbec, allocate_bec_type, deallocate_bec_type
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USE cgcom
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!
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IMPLICIT NONE
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INTEGER :: kpoint, ipol
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INTEGER :: i,l, na,nt, ibnd,jbnd, info, ih,jkb, iter
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real(DP) :: upol(3,3)
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real(DP), ALLOCATABLE :: gk(:,:), q(:), overlap(:,:), &
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becp_(:,:), dbec(:,:), dbec_(:,:)
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COMPLEX(DP), ALLOCATABLE :: dvkb(:,:), dvkb1(:,:), work(:,:), &
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& gr(:,:), h(:,:)
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LOGICAL:: precondition, orthonormal,startwith0
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EXTERNAL H_h
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data upol /1.0d0,0.0d0,0.0d0, 0.0d0,1.0d0,0.0d0, 0.0d0,0.0d0,1.0d0/
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!
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CALL start_clock('dvpsi_e')
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!
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! becp contains <beta|psi> - used in H_h
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!
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CALL allocate_bec_type ( nkb, nbnd, becp )
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ALLOCATE ( gk ( 3, npwx) )
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ALLOCATE ( dvkb ( npwx, nkb) )
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ALLOCATE ( dvkb1( npwx, nkb) )
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ALLOCATE ( becp_(nkb,nbnd), dbec ( nkb, nbnd), dbec_(nkb, nbnd) )
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!
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DO i = 1,npw
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gk(1,i) = (xk(1,kpoint)+g(1,igk(i)))*tpiba
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gk(2,i) = (xk(2,kpoint)+g(2,igk(i)))*tpiba
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gk(3,i) = (xk(3,kpoint)+g(3,igk(i)))*tpiba
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g2kin(i)= gk(1,i)**2 + gk(2,i)**2 + gk(3,i)**2
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ENDDO
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!
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! this is the kinetic contribution to [H,x]: -2i (k+G)_ipol * psi
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!
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DO ibnd = 1,nbnd
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DO i = 1,npw
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dpsi(i,ibnd) = gk(ipol,i)*(0.0d0,-2.0d0) * evc(i,ibnd)
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ENDDO
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ENDDO
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!
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DO i = 1,npw
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IF (g2kin(i)>1.0d-10) THEN
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gk(1,i) = gk(1,i)/sqrt(g2kin(i))
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gk(2,i) = gk(2,i)/sqrt(g2kin(i))
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gk(3,i) = gk(3,i)/sqrt(g2kin(i))
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ENDIF
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ENDDO
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!
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! and these are the contributions from nonlocal pseudopotentials
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! ( upol(3,3) are the three unit vectors along x,y,z)
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!
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CALL gen_us_dj(kpoint,dvkb)
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CALL gen_us_dy(kpoint,upol(1,ipol),dvkb1)
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!
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DO jkb = 1, nkb
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DO i = 1,npw
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dvkb(i,jkb) =(0.d0,-1.d0)*(dvkb1(i,jkb) + dvkb(i,jkb)*gk(ipol,i))
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ENDDO
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ENDDO
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!
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CALL calbec ( npw, vkb, evc, becp )
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CALL calbec ( npw, dvkb, evc, dbec )
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!
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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 (nt==ityp(na)) THEN
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DO ih=1,nh(nt)
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jkb=jkb+1
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DO ibnd = 1,nbnd
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dbec_(jkb,ibnd) = dbec(jkb,ibnd)*dvan(ih,ih,nt)
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becp_(jkb,ibnd) =becp%r(jkb,ibnd)*dvan(ih,ih,nt)
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ENDDO
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ENDDO
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ENDIF
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ENDDO
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ENDDO
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!
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IF (jkb/=nkb) CALL errore('dvpsi_e','unexpected error',1)
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!
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CALL dgemm ('N', 'N', 2*npw, nbnd, nkb,-1.d0, vkb, &
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2*npwx, dbec_, nkb, 1.d0, dpsi, 2*npwx)
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CALL dgemm ('N', 'N', 2*npw, nbnd, nkb, 1.d0,dvkb, &
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2*npwx, becp_, nkb, 1.d0, dpsi, 2*npwx)
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!
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DEALLOCATE(dbec, dbec_, becp_)
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DEALLOCATE(dvkb1)
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DEALLOCATE(dvkb)
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DEALLOCATE(gk)
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!
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! dpsi contains now [H,x] psi_v for the three cartesian polarizations.
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! Now solve the linear systems (H-e_v)*(x*psi_v) = [H,x]*psi_v
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!
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ALLOCATE ( overlap( nbnd, nbnd))
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ALLOCATE ( work( npwx, nbnd))
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ALLOCATE ( gr( npwx, nbnd))
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ALLOCATE ( h ( npwx, nbnd))
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ALLOCATE ( q ( npwx))
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!
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orthonormal = .false.
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precondition= .true.
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!
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IF (precondition) THEN
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DO i = 1,npw
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q(i) = 1.0d0/max(1.d0,g2kin(i))
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ENDDO
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CALL zvscal(npw,npwx,nbnd,q,evc,work)
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CALL calbec ( npw, work, evc, overlap )
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CALL DPOTRF('U',nbnd,overlap,nbnd,info)
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IF (info/=0) CALL errore('solve_ph','cannot factorize',info)
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ENDIF
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!
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startwith0= .true.
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dvpsi(:,:) = (0.d0, 0.d0)
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!
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CALL cgsolve (H_h,npw,evc,npwx,nbnd,overlap,nbnd, &
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orthonormal,precondition,q,startwith0,et(1,kpoint),&
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dpsi,gr,h,dpsi,work,niter_ph,tr2_ph,iter,dvpsi)
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!
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DEALLOCATE(q)
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DEALLOCATE(h)
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DEALLOCATE(gr)
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DEALLOCATE(work)
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DEALLOCATE(overlap)
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CALL deallocate_bec_type ( becp )
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!
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CALL stop_clock('dvpsi_e')
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!
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RETURN
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END SUBROUTINE dvpsi_e
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