quantum-espresso/GWW/bse/h_h.f90

69 lines
1.8 KiB
Fortran

!
! Copyright (C) 2003-2007 Quantum ESPRESSO group
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
!
!-----------------------------------------------------------------------
SUBROUTINE H_h(e,h,Ah)
!-----------------------------------------------------------------------
!
USE kinds, ONLY: DP
USE wvfct, ONLY: npwx, npw, g2kin
USE gvect, ONLY : gstart
USE uspp, ONLY : vkb, nkb
USE lsda_mod, ONLY : current_spin
USE scf, ONLY : vrs
USE becmod, ONLY: bec_type, becp, calbec
! USE cgcom
USE electrons_base, ONLY: nel
use bse_wannier, ONLY:num_nbndv
!
IMPLICIT NONE
!
real(DP):: e(num_nbndv(1))
COMPLEX(DP):: h(npwx,num_nbndv(1)), Ah(npwx,num_nbndv(1))
! real(DP), allocatable :: e(:)
! COMPLEX(DP), allocatable :: h(:,:), Ah(:,:)
!
INTEGER:: j,ibnd,nbnd
!
CALL start_clock('h_h')
! valid only for non-spin resolved calculations
nbnd=num_nbndv(1)
!
! [(k+G)^2 - e ]psi
DO ibnd = 1,nbnd
! set to zero the imaginary part of h at G=0
! needed for numerical stability
IF (gstart==2) h(1,ibnd) = cmplx( dble(h(1,ibnd)),0.d0,kind=DP)
DO j = 1,npw
ah(j,ibnd) = (g2kin(j)-e(ibnd)) * h(j,ibnd)
ENDDO
ENDDO
! V_Loc psi
CALL vloc_psi_gamma(npwx, npw, nbnd, h, vrs(1,current_spin), ah)
! V_NL psi
CALL calbec ( npw, vkb, h, becp, nbnd )
IF (nkb > 0) CALL add_vuspsi (npwx, npw, nbnd, ah)
! set to zero the imaginary part of ah at G=0
! needed for numerical stability
IF (gstart==2) THEN
DO ibnd = 1, nbnd
ah(1,ibnd) = cmplx( dble(ah(1,ibnd)),0.d0,kind=DP)
ENDDO
ENDIF
! DEALLOCATE(h)
! DEALLOCATE(Ah)
! DEALLOCATE(e)
!
CALL stop_clock('h_h')
!
RETURN
END SUBROUTINE H_h