mirror of https://gitlab.com/QEF/q-e.git
84 lines
2.3 KiB
Fortran
84 lines
2.3 KiB
Fortran
!
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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 hdiag( npw, max_iter, avg_iter, et_ )
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!
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! Diagonalizes the unperturbed Hamiltonian in a non-selfconsistent way
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! by Conjugate Gradient (band-by-band)
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!
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USE kinds, ONLY : DP
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USE gvect, ONLY: g, gstart
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USE wvfct, ONLY: g2kin, nbnd, npwx
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USE uspp, ONLY: vkb, okvan
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USE noncollin_module, ONLY: npol
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USE wavefunctions,ONLY: evc
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USE ramanm, ONLY: eth_ns
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implicit none
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!
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! I/O variables:
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!
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integer :: npw, max_iter
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! maximum number of iterations
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real(DP) :: avg_iter, et_(nbnd)
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! iteration number in the diagonalization
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! eigenvalues of the diagonalization
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!
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! Local variables:
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!
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REAL(DP) :: cg_iter
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! number of iteration in CG
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INTEGER :: ig, ntry, notconv
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! counter on G vectors
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! number or repeated call to diagonalization in case of non convergence
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! number of notconverged elements
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INTEGER, ALLOCATABLE :: btype(:)
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! type of band: valence (1) or conduction (0)
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REAl(DP), ALLOCATABLE :: h_prec(:)
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! preconditioning matrix (diagonal)
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! CG diagonalization uses these external routines on a single band
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external h_1psi, s_1psi
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! subroutine h_1psi(npwx,npw,psi,hpsi,spsi) computes H*psi and S*psi
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! subroutine s_1psi(npwx,npw,psi,spsi) computes S*psi (if needed)
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call start_clock ('hdiag')
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allocate (h_prec( npwx), btype(nbnd))
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!
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! various initializations
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!
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btype(:) = 1
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!
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! Conjugate-Gradient diagonalization
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!
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h_prec=1.0_DP
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do ig = 1, npw
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h_prec (ig) = max (1.d0, g2kin (ig) )
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enddo
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ntry = 0
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10 continue
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if (ntry > 0) then
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call rotate_wfc &
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( npwx, npw, nbnd, gstart, nbnd, evc, npol, okvan, evc, et_ )
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avg_iter = avg_iter + 1.d0
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endif
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CALL ccgdiagg( h_1psi, s_1psi, h_prec, &
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npwx, npw, nbnd, npol, evc, et_, btype, eth_ns, &
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max_iter, .true., notconv, cg_iter)
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avg_iter = avg_iter + cg_iter
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ntry = ntry + 1
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if (ntry.le.5.and.notconv.gt.0) goto 10
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deallocate (btype, h_prec)
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call stop_clock ('hdiag')
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return
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end subroutine hdiag
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