mirror of https://gitlab.com/QEF/q-e.git
222 lines
6.7 KiB
Fortran
222 lines
6.7 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 mix_potential (ndim, vout, vin, alphamix, dr2, tr2, &
|
|
iter, n_iter, file_extension, conv)
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
! Modified Broyden's method for potential/charge density mixing
|
|
! D.D.Johnson, PRB 38, 12807 (1988)
|
|
! On input :
|
|
! ndim dimension of arrays vout, vin
|
|
! vout output potential/rho at current iteration
|
|
! vin potential/rho at previous iteration
|
|
! alphamix mixing factor (0 < alphamix <= 1)
|
|
! tr2 threshold for selfconsistency
|
|
! iter current iteration number
|
|
! n_iter number of iterations used in the mixing
|
|
! file_extension if present save previous iterations on
|
|
! file 'prefix'.'file_extension'
|
|
! otherwise keep everything in memory
|
|
! On output:
|
|
! dr2 [(vout-vin)/ndim]^2
|
|
! vin mixed potential
|
|
! vout vout-vin
|
|
! conv true if dr2.le.tr2
|
|
USE kinds, only : DP
|
|
USE mp_global, ONLY : intra_pool_comm
|
|
USE mp, ONLY : mp_sum
|
|
implicit none
|
|
!
|
|
! First the dummy variables
|
|
!
|
|
character (len=256) :: file_extension
|
|
integer :: ndim, iter, n_iter
|
|
real(DP) :: vout (ndim), vin (ndim), alphamix, dr2, tr2
|
|
logical :: conv
|
|
!
|
|
! Here the local variables
|
|
!
|
|
! max number of iterations used in mixing: n_iter must be .le. maxter
|
|
integer :: maxter
|
|
parameter (maxter = 8)
|
|
!
|
|
integer :: iunit, iunmix, n, i, j, iwork (maxter), info, iter_used, &
|
|
ipos, inext, ndimtot
|
|
! work space containing info from previous iterations:
|
|
! must be kept in memory and saved between calls if file_extension=' '
|
|
real(DP), allocatable, save :: df (:,:), dv (:,:)
|
|
!
|
|
real(DP), allocatable :: vinsave (:)
|
|
real(DP) :: beta (maxter, maxter), gamma, work (maxter), norm
|
|
logical :: saveonfile, opnd, exst
|
|
real(DP), external :: ddot, dnrm2
|
|
! adjustable parameters as suggested in the original paper
|
|
real(DP) w (maxter), w0
|
|
data w0 / 0.01d0 /, w / maxter * 1.d0 /
|
|
!
|
|
!
|
|
call start_clock ('mix_pot')
|
|
if (iter.lt.1) call errore ('mix_potential', 'iter is wrong', 1)
|
|
if (n_iter.gt.maxter) call errore ('mix_potential', 'n_iter too big', 1)
|
|
if (ndim.le.0) call errore ('mix_potential', 'ndim .le. 0', 3)
|
|
!
|
|
saveonfile = file_extension.ne.' '
|
|
!
|
|
do n = 1, ndim
|
|
vout (n) = vout (n) - vin (n)
|
|
enddo
|
|
dr2 = dnrm2 (ndim, vout, 1) **2
|
|
ndimtot = ndim
|
|
#ifdef __PARA
|
|
call mp_sum (dr2, intra_pool_comm)
|
|
call mp_sum (ndimtot, intra_pool_comm)
|
|
#endif
|
|
dr2 = (sqrt (dr2) / ndimtot) **2
|
|
|
|
conv = dr2.lt.tr2
|
|
if (saveonfile) then
|
|
do iunit = 99, 1, - 1
|
|
inquire (unit = iunit, opened = opnd)
|
|
iunmix = iunit
|
|
if (.not.opnd) goto 10
|
|
enddo
|
|
call errore ('mix_potential', 'free unit not found?!?', 1)
|
|
10 continue
|
|
if (conv) then
|
|
! remove temporary file (open and close it)
|
|
call diropn (iunmix, file_extension, ndim, exst)
|
|
close (unit=iunmix, status='delete')
|
|
call stop_clock ('mix_pot')
|
|
return
|
|
endif
|
|
call diropn (iunmix, file_extension, ndim, exst)
|
|
if (iter.gt.1.and..not.exst) then
|
|
call infomsg ('mix_potential', 'file not found, restarting')
|
|
iter = 1
|
|
endif
|
|
allocate (df( ndim , n_iter))
|
|
allocate (dv( ndim , n_iter))
|
|
else
|
|
if (iter.eq.1) then
|
|
allocate (df( ndim , n_iter))
|
|
allocate (dv( ndim , n_iter))
|
|
endif
|
|
if (conv) then
|
|
deallocate (dv)
|
|
deallocate (df)
|
|
call stop_clock ('mix_pot')
|
|
return
|
|
endif
|
|
allocate (vinsave( ndim))
|
|
endif
|
|
!
|
|
! iter_used = iter-1 if iter <= n_iter
|
|
! iter_used = n_iter if iter > n_iter
|
|
!
|
|
iter_used = min (iter - 1, n_iter)
|
|
!
|
|
! ipos is the position in which results from the present iteraction
|
|
! are stored. ipos=iter-1 until ipos=n_iter, then back to 1,2,...
|
|
!
|
|
ipos = iter - 1 - ( (iter - 2) / n_iter) * n_iter
|
|
!
|
|
if (iter.gt.1) then
|
|
if (saveonfile) then
|
|
call davcio (df (1, ipos), ndim, iunmix, 1, - 1)
|
|
call davcio (dv (1, ipos), ndim, iunmix, 2, - 1)
|
|
endif
|
|
do n = 1, ndim
|
|
df (n, ipos) = vout (n) - df (n, ipos)
|
|
dv (n, ipos) = vin (n) - dv (n, ipos)
|
|
enddo
|
|
norm = (dnrm2 (ndim, df (1, ipos), 1) ) **2
|
|
#ifdef __PARA
|
|
call mp_sum (norm, intra_pool_comm)
|
|
#endif
|
|
norm = sqrt (norm)
|
|
call dscal (ndim, 1.d0 / norm, df (1, ipos), 1)
|
|
call dscal (ndim, 1.d0 / norm, dv (1, ipos), 1)
|
|
endif
|
|
!
|
|
if (saveonfile) then
|
|
do i = 1, iter_used
|
|
if (i.ne.ipos) then
|
|
call davcio (df (1, i), ndim, iunmix, 2 * i + 1, - 1)
|
|
call davcio (dv (1, i), ndim, iunmix, 2 * i + 2, - 1)
|
|
endif
|
|
enddo
|
|
call davcio (vout, ndim, iunmix, 1, 1)
|
|
call davcio (vin, ndim, iunmix, 2, 1)
|
|
if (iter.gt.1) then
|
|
call davcio (df (1, ipos), ndim, iunmix, 2 * ipos + 1, 1)
|
|
call davcio (dv (1, ipos), ndim, iunmix, 2 * ipos + 2, 1)
|
|
endif
|
|
else
|
|
call DCOPY (ndim, vin, 1, vinsave, 1)
|
|
endif
|
|
!
|
|
do i = 1, iter_used
|
|
do j = i + 1, iter_used
|
|
beta (i, j) = w (i) * w (j) * ddot (ndim, df (1, j), 1, df (1, i), 1)
|
|
#ifdef __PARA
|
|
call mp_sum ( beta (i, j), intra_pool_comm )
|
|
#endif
|
|
enddo
|
|
beta (i, i) = w0**2 + w (i) **2
|
|
enddo
|
|
!
|
|
call DSYTRF ('U', iter_used, beta, maxter, iwork, work, maxter, info)
|
|
call errore ('broyden', 'factorization', info)
|
|
call DSYTRI ('U', iter_used, beta, maxter, iwork, work, info)
|
|
call errore ('broyden', 'DSYTRI', info)
|
|
!
|
|
do i = 1, iter_used
|
|
do j = i + 1, iter_used
|
|
beta (j, i) = beta (i, j)
|
|
enddo
|
|
enddo
|
|
!
|
|
do i = 1, iter_used
|
|
work (i) = ddot (ndim, df (1, i), 1, vout, 1)
|
|
enddo
|
|
#ifdef __PARA
|
|
call mp_sum ( work(1:iter_used), intra_pool_comm )
|
|
#endif
|
|
!
|
|
do n = 1, ndim
|
|
vin (n) = vin (n) + alphamix * vout (n)
|
|
enddo
|
|
!
|
|
do i = 1, iter_used
|
|
gamma = 0.d0
|
|
do j = 1, iter_used
|
|
gamma = gamma + beta (j, i) * w (j) * work (j)
|
|
enddo
|
|
!
|
|
do n = 1, ndim
|
|
vin (n) = vin (n) - w (i) * gamma * (alphamix * df (n, i) + dv (n, i) )
|
|
enddo
|
|
enddo
|
|
!
|
|
if (saveonfile) then
|
|
close (iunmix, status='keep')
|
|
deallocate(dv)
|
|
deallocate(df)
|
|
else
|
|
inext = iter - ( (iter - 1) / n_iter) * n_iter
|
|
call DCOPY (ndim, vout, 1, df (1, inext), 1)
|
|
call DCOPY (ndim, vinsave, 1, dv (1, inext), 1)
|
|
deallocate(vinsave)
|
|
endif
|
|
call stop_clock ('mix_pot')
|
|
return
|
|
end subroutine mix_potential
|
|
|