mirror of https://gitlab.com/QEF/q-e.git
96 lines
2.4 KiB
Fortran
96 lines
2.4 KiB
Fortran
!
|
|
! Copyright (C) 2001 PWSCF 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 hdiag( max_iter, avg_iter, xk_, et_ )
|
|
!
|
|
! Diagonalizes the unperturbed Hamiltonian in a non-selfconsistent way
|
|
! by Conjugate Gradient (band-by-band)
|
|
!
|
|
#include "f_defs.h"
|
|
use kinds, only : DP
|
|
use pwcom, ONLY: g, g2kin, tpiba2, ecfixed, qcutz, q2sigma, nbnd, &
|
|
npwx, vkb, igk, npw
|
|
use g_psi_mod
|
|
USE wavefunctions_module, ONLY: evc
|
|
USE ramanm, ONLY: eth_ns
|
|
implicit none
|
|
|
|
!
|
|
! I/O variables:
|
|
!
|
|
integer :: max_iter
|
|
! maximum number of iterations
|
|
real(DP) :: avg_iter, xk_(3), et_(nbnd)
|
|
! iteration number in the diagonalization
|
|
! k-point
|
|
! eigenvalues of the diagonalization
|
|
!
|
|
! Local variables:
|
|
!
|
|
real(DP) :: cg_iter, erf
|
|
! number of iteration in CG
|
|
! error function
|
|
integer :: ig, ntry, notconv
|
|
! counter on G vectors
|
|
! number or repeated call to diagonalization in case of non convergence
|
|
! number of notconverged elements
|
|
INTEGER, ALLOCATABLE :: btype(:)
|
|
! type of band: valence (1) or conduction (0)
|
|
|
|
call start_clock ('hdiag')
|
|
|
|
allocate (h_diag( npwx), btype(nbnd))
|
|
btype(:) = 1
|
|
!
|
|
! various initializations
|
|
!
|
|
call init_us_2 (npw, igk, xk_, vkb)
|
|
!
|
|
! sets the kinetic energy
|
|
!
|
|
do ig = 1, npw
|
|
g2kin (ig) =((xk_ (1) + g (1, igk (ig) ) ) **2 + &
|
|
(xk_ (2) + g (2, igk (ig) ) ) **2 + &
|
|
(xk_ (3) + g (3, igk (ig) ) ) **2 ) * tpiba2
|
|
enddo
|
|
!
|
|
! if (qcutz > 0.d0) then
|
|
! do ig = 1, npw
|
|
! g2kin (ig) = g2kin (ig) + qcutz * (1.d0 + erf ( (g2kin (ig) &
|
|
! - ecfixed) / q2sigma) )
|
|
! enddo
|
|
! endif
|
|
|
|
!
|
|
! Conjugate-Gradient diagonalization
|
|
! h_diag is the precondition matrix
|
|
!
|
|
do ig = 1, npw
|
|
h_diag (ig) = max (1.d0, g2kin (ig) )
|
|
enddo
|
|
ntry = 0
|
|
10 continue
|
|
if (ntry > 0) then
|
|
call cinitcgg (npwx, npw, nbnd, nbnd, evc, evc, et_ )
|
|
avg_iter = avg_iter + 1.d0
|
|
endif
|
|
call ccgdiagg (npwx, npw, nbnd, evc, et_, btype, h_diag, eth_ns, &
|
|
max_iter, .true., notconv, cg_iter)
|
|
avg_iter = avg_iter + cg_iter
|
|
ntry = ntry + 1
|
|
|
|
if (ntry.le.5.and.notconv.gt.0) goto 10
|
|
|
|
deallocate (btype, h_diag)
|
|
call stop_clock ('hdiag')
|
|
|
|
return
|
|
end subroutine hdiag
|
|
|