mirror of https://gitlab.com/QEF/q-e.git
625 lines
20 KiB
Fortran
625 lines
20 KiB
Fortran
!
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! Copyright (C) 2001-2004 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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#include "machine.h"
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!
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!----------------------------------------------------------------------------
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SUBROUTINE c_bands( iter, ik_, dr2 )
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!----------------------------------------------------------------------------
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!
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! ... this is a wrapper to specific calls
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!
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! ... internal procedures :
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!
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! ... c_bands_gamma() : for gamma sampling of the BZ (optimized algorithms)
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! ... c_bands_k() : for arbitrary BZ sampling (general algorithm)
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! ... test_exit_cond() : the test on the iterative diagonalization
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!
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!
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USE kinds, ONLY : DP
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USE constants, ONLY : eps4
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USE io_global, ONLY : stdout
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USE wvfct, ONLY : gamma_only
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USE io_files, ONLY : iunigk, nwordatwfc, iunat, iunwfc, nwordwfc
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USE cell_base, ONLY : tpiba2
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USE klist, ONLY : nkstot, nks, xk, nelec
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USE us, ONLY : okvan, vkb, nkb
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USE gvect, ONLY : g, gstart, ecfixed, qcutz, q2sigma, nrxx, &
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nr1, nr2, nr3
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USE wvfct, ONLY : g2kin, wg, nbndx, et, nbnd, npwx, igk, &
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npw
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USE control_flags, ONLY : diis_ndim, istep, ethr, lscf, max_cg_iter, &
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diis_ethr_cg, isolve, reduce_io
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USE ldaU, ONLY : lda_plus_u, swfcatom
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USE scf, ONLY : vltot
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USE lsda_mod, ONLY : current_spin, lsda, isk
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USE wavefunctions_module, ONLY : evc
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USE g_psi_mod, ONLY : h_diag, s_diag
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USE diis_module, ONLY : cdiisg, rdiisg
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!
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IMPLICIT NONE
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!
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! ... First the I/O variables
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!
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INTEGER :: ik_, iter
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! k-point already done
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! current iterations
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REAL(KIND=DP) :: dr2
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! current accuracy of self-consistency
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!
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! ... local variables
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!
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REAL(KIND=DP) :: avg_iter, v_of_0
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! average number of iterations
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! the average of the potential
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INTEGER :: ik, ig, ibnd, dav_iter, diis_iter, ntry, notconv
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! counter on k points
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! counter on G vectors
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! counter on bands
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! number of iterations in Davidson
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! number of iterations in DIIS
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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: conduction (1) or valence (0)
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!
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! ... external functions
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!
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REAL(KIND=DP), EXTERNAL :: erf
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! error function
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!
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!
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CALL start_clock( 'c_bands' )
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!
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IF ( ik_ == nks ) THEN
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!
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ik_ = 0
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!
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RETURN
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!
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END IF
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!
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! ... allocate arrays
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!
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ALLOCATE( h_diag( npwx ) )
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ALLOCATE( s_diag( npwx ) )
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!
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! ... allocate specific array for DIIS
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!
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IF ( isolve == 2 ) ALLOCATE( btype( nbnd ) )
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!
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IF ( gamma_only ) THEN
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!
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CALL c_bands_gamma()
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!
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ELSE
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!
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CALL c_bands_k()
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!
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END IF
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!
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! ... deallocate arrays
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!
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DEALLOCATE( s_diag )
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DEALLOCATE( h_diag )
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!
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IF ( isolve == 2 ) DEALLOCATE( btype )
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!
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CALL stop_clock( 'c_bands' )
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!
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RETURN
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!
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CONTAINS
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!
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! ... internal procedures
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!
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!-----------------------------------------------------------------------
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SUBROUTINE c_bands_gamma()
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!-----------------------------------------------------------------------
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!
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! ... This routine is a driver for the diagonalization routines of the
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! ... total Hamiltonian at Gammma point only
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! ... It reads the Hamiltonian and an initial guess of the wavefunctions
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! ... from a file and computes initialization quantities for the
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! ... diagonalization routines.
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! ... There are two types of iterative diagonalization:
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! ... a) Davidson algorithm (all-band)
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! ... c) DIIS algorithm (all-band)
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!
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USE rbecmod, ONLY: becp
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!
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IMPLICIT NONE
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!
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!
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! ... becp contains <beta|psi> - used in h_psi and s_psi
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!
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ALLOCATE( becp( nkb, nbnd ) )
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!
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IF ( isolve == 0 ) THEN
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!
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WRITE( stdout, '(5X,"Davidson diagonalization with overlap")' )
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!
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ELSE IF ( isolve == 2 ) THEN
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!
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WRITE( stdout, '(5X,"DIIS style diagonalization")')
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!
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ELSE
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!
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CALL errore( 'c_bands', 'CG diagonalization not implemented', 1 )
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!
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END IF
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!
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avg_iter = 0.D0
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!
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! ... v_of_0 is (Vloc)(G=0)
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!
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v_of_0 = SUM( vltot(1:nrxx) ) / REAL( nr1 * nr2 * nr3 )
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!
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CALL reduce( 1, v_of_0 )
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!
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IF ( nks > 1 ) REWIND( iunigk )
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!
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! ... For each k point diagonalizes the hamiltonian
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!
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k_loop: DO ik = 1, nks
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!
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IF ( lsda ) current_spin = isk(ik)
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!
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! ... Reads the Hamiltonian and the list k+G <-> G of this k point
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!
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IF ( nks > 1 ) READ( iunigk ) npw, igk
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!
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! ... do not recalculate k-points if restored from a previous run
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!
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IF ( ik <= ik_ ) THEN
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!
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CALL save_in_cbands( iter, ik, dr2 )
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!
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CYCLE k_loop
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!
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END IF
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!
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! ... various initializations
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!
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IF ( nkb > 0 ) &
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CALL init_us_2( npw, igk, xk(1,ik), vkb )
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!
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! ... read in wavefunctions from the previous iteration
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!
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IF ( nks > 1 .OR. .NOT. reduce_io ) &
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call davcio( evc, nwordwfc, iunwfc, ik, -1 )
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!
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! ... Needed for LDA+U
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!
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IF ( lda_plus_u ) CALL davcio( swfcatom, nwordatwfc, iunat, ik, -1 )
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!
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! ... sets the kinetic energy
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!
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g2kin(1:npw) = ( ( xk(1,ik) + g(1,igk(1:npw)) )**2 + &
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( xk(2,ik) + g(2,igk(1:npw)) )**2 + &
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( xk(3,ik) + g(3,igk(1:npw)) )**2 ) * tpiba2
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!
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IF ( qcutz > 0.D0 ) THEN
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!
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DO ig = 1, npw
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g2kin(ig) = g2kin(ig) + qcutz * &
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( 1.D0 + erf( (g2kin(ig) - ecfixed ) / q2sigma ) )
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END DO
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!
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END IF
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!
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IF ( isolve == 2 ) THEN
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!
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! ... RMM-DIIS method
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!
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h_diag(1:npw) = g2kin(1:npw) + v_of_0
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!
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CALL usnldiag( h_diag, s_diag )
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!
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ntry = 0
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diis_iter = 0.D0
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!
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btype(:) = 1
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!
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IF ( iter == 1 ) THEN
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!
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! ... at the first iteration a static criterium is used to
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! ... define whether or not a band is occupied
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!
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FORALL( ibnd = 1 : nbnd, &
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ibnd > ( INT( nelec / 2.D0 ) + 4 ) ) btype(ibnd) = 0
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!
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ELSE
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!
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! ... a band is considered empty when its occupation is less
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! ... than 1.0 %
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!
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WHERE( wg(:,ik) < 0.01D0 ) btype(:) = 0
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!
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END IF
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!
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RMMDIIS_loop: DO
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!
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CALL rdiisg( npw, npwx, nbnd, diis_ndim, evc, &
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et(:,ik), ethr, btype, notconv, diis_iter, iter )
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!
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avg_iter = avg_iter + diis_iter
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!
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! ... save wave-functions to be used as input for the
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! ... iterative diagonalization of the next scf iteration
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! ... and for rho calculation
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!
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IF ( nks > 1 .OR. .NOT. reduce_io ) &
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CALL davcio( evc, nwordwfc, iunwfc, ik, 1 )
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!
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ntry = ntry + 1
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!
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! ... exit condition
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!
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IF ( test_exit_cond() ) EXIT RMMDIIS_loop
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!
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END DO RMMDIIS_loop
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!
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ELSE
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!
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! ... Davidson diagonalization
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!
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! ... h_diag are the diagonal matrix elements of the
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! ... hamiltonian used in g_psi to evaluate the correction
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! ... to the trial eigenvectors
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!
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h_diag(1:npw) = g2kin(1:npw) + v_of_0
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!
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CALL usnldiag( h_diag, s_diag )
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!
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ntry = 0
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!
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david_loop: DO
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!
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CALL regterg( npw, npwx, nbnd, nbndx, evc, ethr, &
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okvan, gstart, et(1,ik), notconv, dav_iter )
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!
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avg_iter = avg_iter + dav_iter
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!
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! ... save wave-functions to be used as input for the
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! ... iterative diagonalization of the next scf iteration
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! ... and for rho calculation
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!
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IF ( nks > 1 .OR. .NOT. reduce_io ) &
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CALL davcio( evc, nwordwfc, iunwfc, ik, 1 )
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!
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ntry = ntry + 1
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!
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! ... exit condition
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!
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IF ( test_exit_cond() ) EXIT david_loop
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!
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END DO david_loop
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!
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END IF
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!
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IF ( notconv > MAX( 5, nbnd / 4 ) ) THEN
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!
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CALL errore( 'c_bands', &
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& 'too many bands are not converged', 1 )
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!
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END IF
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!
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! ... save restart information
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!
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CALL save_in_cbands( iter, ik, dr2 )
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!
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END DO k_loop
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!
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ik_ = 0
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!
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CALL poolreduce( 1, avg_iter )
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!
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avg_iter = avg_iter / nkstot
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!
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WRITE( stdout, &
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'( 5X,"ethr = ",1PE9.2,", avg # of iterations =",0PF5.1 )' ) &
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ethr, avg_iter
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!
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! ... deallocate work space
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!
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DEALLOCATE( becp )
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!
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RETURN
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!
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END SUBROUTINE c_bands_gamma
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!
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!
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!-----------------------------------------------------------------------
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SUBROUTINE c_bands_k()
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!-----------------------------------------------------------------------
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!
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! ... This routine is a driver for the diagonalization routines of the
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! ... total Hamiltonian at each k-point.
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! ... It reads the Hamiltonian and an initial guess of the wavefunctions
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! ... from a file and computes initialization quantities for the
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! ... diagonalization routines.
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! ... There are three types of iterative diagonalization:
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! ... a) Davidson algorithm (all-band)
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! ... b) Conjugate Gradient (band-by-band)
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! ... c) DIIS algorithm
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!
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USE becmod, ONLY: becp
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!
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IMPLICIT NONE
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!
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! ... here the local variables
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!
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REAL(KIND=DP) :: cg_iter
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! number of iteration in CG
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! number of iteration in DIIS
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!
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! ... becp contains <beta|psi> - used in h_psi and s_psi
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!
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ALLOCATE( becp( nkb, nbnd ) )
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!
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! ... allocate specific array for DIIS
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!
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!
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IF ( isolve == 0 ) THEN
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!
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WRITE( stdout, '(5X,"Davidson diagonalization (with overlap)")')
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!
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ELSE IF ( isolve == 1 ) THEN
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!
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WRITE( stdout, '(5X,"Conjugate-gradient style diagonalization")')
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!
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ELSE IF ( isolve == 2 ) THEN
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!
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WRITE( stdout, '(5X,"DIIS style diagonalization")')
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!
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ELSE
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!
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CALL errore( 'c_bands', 'isolve not implemented', 1 )
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!
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END IF
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!
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avg_iter = 0.D0
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!
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! ... v_of_0 is (Vloc)(G=0)
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!
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v_of_0 = SUM( vltot(1:nrxx) ) / REAL( nr1 * nr2 * nr3 )
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!
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CALL reduce( 1, v_of_0 )
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!
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if ( nks > 1 ) REWIND( iunigk )
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!
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! ... For each k point diagonalizes the hamiltonian
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!
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k_loop: DO ik = 1, nks
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!
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IF ( lsda ) current_spin = isk(ik)
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!
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! ... Reads the Hamiltonian and the list k+G <-> G of this k point
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!
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IF ( nks > 1 ) READ( iunigk ) npw, igk
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!
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! ... do not recalculate k-points if restored from a previous run
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!
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IF ( ik <= ik_ ) THEN
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!
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CALL save_in_cbands( iter, ik, dr2 )
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!
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CYCLE k_loop
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!
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END IF
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!
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! ... various initializations
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!
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IF ( nkb > 0 ) &
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CALL init_us_2( npw, igk, xk(1,ik), vkb )
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!
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! ... read in wavefunctions from the previous iteration
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!
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IF ( nks > 1 .OR. .NOT. reduce_io ) &
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CALL davcio( evc, nwordwfc, iunwfc, ik, -1 )
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!
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! ... Needed for LDA+U
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!
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IF ( lda_plus_u ) CALL davcio( swfcatom, nwordatwfc, iunat, ik, -1 )
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!
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! ... sets the kinetic energy
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!
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g2kin(1:npw) = ( ( xk(1,ik) + g(1,igk(1:npw)) )**2 + &
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( xk(2,ik) + g(2,igk(1:npw)) )**2 + &
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( xk(3,ik) + g(3,igk(1:npw)) )**2 ) * tpiba2
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!
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!
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IF ( qcutz > 0.D0 ) THEN
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DO ig = 1, npw
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g2kin (ig) = g2kin(ig) + qcutz * &
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( 1.D0 + erf( ( g2kin(ig) - ecfixed ) / q2sigma ) )
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END DO
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END IF
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!
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IF ( isolve == 1 ) THEN
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!
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! ... Conjugate-Gradient diagonalization
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!
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! ... h_diag is the precondition matrix
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!
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h_diag(1:npw) = MAX( 1.D0, g2kin(1:npw) )
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!
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ntry = 0
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!
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CG_loop : DO
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!
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IF ( iter /= 1 .OR. istep /= 1 .OR. ntry > 0 ) THEN
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!
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CALL cinitcgg( npwx, npw, nbnd, nbnd, evc, evc, et(1,ik) )
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!
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avg_iter = avg_iter + 1.D0
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!
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END IF
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!
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CALL ccgdiagg( npwx, npw, nbnd, evc, et(1,ik), h_diag, ethr, &
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max_cg_iter, .not.lscf, notconv, cg_iter )
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!
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avg_iter = avg_iter + cg_iter
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!
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! ... save wave-functions to be used as input for the
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! ... iterative diagonalization of the next scf iteration
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! ... and for rho calculation
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!
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IF ( nks > 1 .OR. .NOT. reduce_io ) &
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CALL davcio( evc, nwordwfc, iunwfc, ik, 1 )
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!
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ntry = ntry + 1
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!
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! ... exit condition
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!
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IF ( test_exit_cond() ) EXIT CG_loop
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!
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END DO CG_loop
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!
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ELSE IF ( isolve == 2 ) THEN
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!
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! ... RMM-DIIS method
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!
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h_diag(1:npw) = g2kin(1:npw) + v_of_0
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!
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CALL usnldiag( h_diag, s_diag )
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!
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ntry = 0
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diis_iter = 0.D0
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!
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btype(:) = 1
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!
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IF ( iter == 1 ) THEN
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!
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! ... at the first iteration a static criterium is used to
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! ... define whether or not a band is occupied
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!
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FORALL( ibnd = 1 : nbnd, &
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ibnd > ( INT( nelec / 2.D0 ) + 4 ) ) btype(ibnd) = 0
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!
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ELSE
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!
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! ... a band is considered empty when its occupation is less
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! ... than 1.0 %
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!
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WHERE( wg(:,ik) < 0.01D0 ) btype(:) = 0
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!
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END IF
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!
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RMMDIIS_loop: DO
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!
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CALL cdiisg( npw, npwx, nbnd, diis_ndim, evc, &
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et(:,ik), ethr, btype, notconv, diis_iter, iter )
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!
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avg_iter = avg_iter + diis_iter
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!
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! ... save wave-functions to be used as input for the
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! ... iterative diagonalization of the next scf iteration
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! ... and for rho calculation
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!
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IF ( nks > 1 .OR. .NOT. reduce_io ) &
|
|
CALL davcio( evc, nwordwfc, iunwfc, ik, 1 )
|
|
!
|
|
ntry = ntry + 1
|
|
!
|
|
! ... exit condition
|
|
!
|
|
IF ( test_exit_cond() ) EXIT RMMDIIS_loop
|
|
!
|
|
END DO RMMDIIS_loop
|
|
!
|
|
ELSE
|
|
!
|
|
! ... Davidson diagonalization
|
|
!
|
|
! ... h_diag are the diagonal matrix elements of the
|
|
! ... hamiltonian used in g_psi to evaluate the correction
|
|
! ... to the trial eigenvectors
|
|
!
|
|
h_diag(1:npw) = g2kin(1:npw) + v_of_0
|
|
!
|
|
CALL usnldiag( h_diag, s_diag )
|
|
!
|
|
ntry = 0
|
|
!
|
|
david_loop: DO
|
|
!
|
|
CALL cegterg( npw, npwx, nbnd, nbndx, evc, ethr, &
|
|
okvan, et(1,ik), notconv, dav_iter )
|
|
!
|
|
avg_iter = avg_iter + dav_iter
|
|
!
|
|
! ... save wave-functions to be used as input for the
|
|
! ... iterative diagonalization of the next scf iteration
|
|
! ... and for rho calculation
|
|
!
|
|
IF ( nks > 1 .OR. .NOT. reduce_io ) &
|
|
CALL davcio( evc, nwordwfc, iunwfc, ik, 1 )
|
|
!
|
|
ntry = ntry + 1
|
|
!
|
|
! ... exit condition
|
|
!
|
|
IF ( test_exit_cond() ) EXIT david_loop
|
|
!
|
|
END DO david_loop
|
|
!
|
|
END IF
|
|
!
|
|
IF ( notconv > MAX( 5, nbnd / 4 ) ) THEN
|
|
!
|
|
CALL errore( 'c_bands', &
|
|
& 'too many bands are not converged', 1 )
|
|
!
|
|
END IF
|
|
!
|
|
! ... save restart information
|
|
!
|
|
CALL save_in_cbands( iter, ik, dr2 )
|
|
!
|
|
END DO k_loop
|
|
!
|
|
ik_ = 0
|
|
!
|
|
CALL poolreduce( 1, avg_iter )
|
|
!
|
|
avg_iter = avg_iter / nkstot
|
|
!
|
|
WRITE( stdout, &
|
|
'( 5X,"ethr = ",1PE9.2,", avg # of iterations =",0PF5.1 )' ) &
|
|
ethr, avg_iter
|
|
!
|
|
! ... deallocate work space
|
|
!
|
|
DEALLOCATE( becp )
|
|
!
|
|
RETURN
|
|
!
|
|
END SUBROUTINE c_bands_k
|
|
!
|
|
!
|
|
!-----------------------------------------------------------------------
|
|
FUNCTION test_exit_cond()
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
! ... this logical function is .TRUE. when iterative diagonalization
|
|
! ... is converged
|
|
!
|
|
IMPLICIT NONE
|
|
!
|
|
LOGICAL :: test_exit_cond
|
|
!
|
|
!
|
|
test_exit_cond = .NOT. ( ( ntry <= 5 ) .AND. &
|
|
( ( .NOT. lscf .AND. ( notconv > 0 ) ) .OR. &
|
|
( lscf .AND. ( notconv > 5 ) ) ) )
|
|
!
|
|
END FUNCTION test_exit_cond
|
|
!
|
|
END SUBROUTINE c_bands
|