[Pw_forum] Error in "from c_bands :"
Carlo Sbraccia
sbraccia at sissa.it
Fri Jan 30 22:29:41 CET 2004
Dear Sergei,
this error is produced by an experimental check performed on the iterative
diagonalization at the first scf iteration: it seems not to be yet well
tuned!
I hope the code attached to this mail could solve the problem (copy this
file in the PW directory).
carlo sbraccia
-------------- next part --------------
!
! Copyright (C) 2001-2004 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 .
!
#include "machine.h"
!
!----------------------------------------------------------------------------
SUBROUTINE c_bands( iter, ik_, dr2 )
!----------------------------------------------------------------------------
!
! ... this is a wrapper to specific calls
!
USE kinds, ONLY : DP
USE io_global, ONLY : stdout
USE wvfct, ONLY : gamma_only
USE io_files, ONLY : iunigk, nwordatwfc, iunat, iunwfc, nwordwfc
USE brilz, ONLY : tpiba2
USE klist, ONLY : nkstot, nks, xk
USE us, ONLY : okvan, vkb, nkb
USE gvect, ONLY : g, gstart, ecfixed, qcutz, q2sigma, nrxx, &
nr1, nr2, nr3
USE wvfct, ONLY : g2kin, wg, nbndx, et, nbnd, npwx, igk, &
npw
USE control_flags, ONLY : diis_ndim, istep, ethr, lscf, max_cg_iter, &
diis_ethr_cg, isolve, reduce_io
USE ldaU, ONLY : lda_plus_u, swfcatom
USE scf, ONLY : vltot
USE lsda_mod, ONLY : current_spin, lsda, isk
USE wavefunctions_module, ONLY : evc
USE g_psi_mod
!
IMPLICIT NONE
!
! ... First the I/O variables
!
INTEGER :: ik_, iter
! k-point already done
! current iterations
REAL(KIND=DP) :: dr2
! current accuracy of self-consistency
!
!
CALL start_clock( 'c_bands' )
!
IF ( gamma_only ) THEN
!
CALL c_bands_gamma()
!
ELSE
!
CALL c_bands_k()
!
END IF
!
CALL stop_clock( 'c_bands' )
!
RETURN
!
CONTAINS
!
!-----------------------------------------------------------------------
SUBROUTINE c_bands_gamma()
!-----------------------------------------------------------------------
!
! ... This routine is a driver for the diagonalization routines of the
! ... total Hamiltonian at Gammma point only
! ... It reads the Hamiltonian and an initial guess of the wavefunctions
! ... from a file and computes initialization quantities for Davidson
! ... iterative diagonalization.
!
USE rbecmod, ONLY: becp, becp_
!
IMPLICIT NONE
!
! ... here the local variables
!
REAL(KIND=DP) :: avg_iter, v_of_0, DSUM, ERF
! average number of iterations
! the average of the potential
! summation function
! error function
INTEGER :: ik, ig, ibnd, ntrt, ntry, notconv
! counter on k points
! counter on G vectors
! counter on bands
! number of iterations in Davidson
! number of repeated call to REGTERG
! number of notconverged elements
LOGICAL :: ltest
! .TRUE. if there are too many not converged bands
!
!
IF ( ik_ == nks ) THEN
!
ik_ = 0
!
RETURN
!
END IF
!
! ... allocate arrays
!
ALLOCATE( h_diag( npwx ) )
ALLOCATE( s_diag( npwx ) )
!
! ... becp, becp_ contain <beta|psi> - used in h_psi and s_psi
! ... they are allocate once here in order to reduce overhead
!
ALLOCATE( becp( nkb, nbnd ), becp_( nkb, nbnd ) )
!
IF ( isolve == 0 ) THEN
WRITE( stdout, '(" Davidson diagonalization with overlap")' )
ELSE
CALL errore( 'c_bands', &
& 'CG and DIIS diagonalization not implemented', 1 )
END IF
!
avg_iter = 0.D0
!
! ... v_of_0 is (Vloc)(G=0)
!
v_of_0 = DSUM( nrxx, vltot, 1 ) / REAL( nr1 * nr2 * nr3 )
!
#if defined (__PARA)
CALL reduce( 1, v_of_0 )
#endif
!
IF ( nks > 1 ) REWIND( iunigk )
!
! ... For each k point diagonalizes the hamiltonian
!
k_loop: DO ik = 1, nks
!
IF ( lsda ) current_spin = isk(ik)
!
! ... Reads the Hamiltonian and the list k+G <-> G of this k point
!
IF ( nks > 1 ) READ( iunigk ) npw, igk
!
! ... do not recalculate k-points if restored from a previous run
!
IF ( ik <= ik_ ) THEN
!
CALL save_in_cbands( iter, ik, dr2 )
!
CYCLE k_loop
!
END IF
!
! ... various initializations
!
IF ( nkb > 0 ) &
CALL init_us_2( npw, igk, xk(1,ik), vkb )
!
! ... read in wavefunctions from the previous iteration
!
IF ( nks > 1 .OR. .NOT. reduce_io ) &
call davcio( evc, nwordwfc, iunwfc, ik, -1 )
!
! ... Needed for LDA+U
!
IF ( lda_plus_u ) CALL davcio( swfcatom, nwordatwfc, iunat, ik, -1 )
!
! ... sets the kinetic energy
!
g2kin(1:npw) = ( ( xk(1,ik) + g(1,igk(1:npw)) )**2 + &
( xk(2,ik) + g(2,igk(1:npw)) )**2 + &
( xk(3,ik) + g(3,igk(1:npw)) )**2 ) * tpiba2
!
IF ( qcutz > 0.D0 ) THEN
!
DO ig = 1, npw
g2kin(ig) = g2kin(ig) + qcutz * &
( 1.D0 + ERF( (g2kin(ig) - ecfixed ) / q2sigma ) )
END DO
!
END IF
!
! ... 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 regterg( npw, npwx, nbnd, nbndx, evc, ethr, okvan, gstart, &
et(1,ik), notconv, ntrt )
!
avg_iter = avg_iter + ntrt
!
! ... 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
!
ltest = .NOT. ( ( ntry <= 5 ) .AND. &
( ( .NOT. lscf .AND. ( notconv > 0 ) ) .OR. &
( lscf .AND. ( notconv > 5 ) ) ) )
!
IF ( ltest ) EXIT david_loop
!
END DO david_loop
!
IF ( notconv /= 0 ) &
WRITE( stdout, '(" warning : ",I3," eigenvectors not",&
&" converged after ",I3," attemps")') notconv, ntry
!
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
!
#if defined (__PARA)
CALL poolreduce( 1, avg_iter )
#endif
!
avg_iter = avg_iter / nkstot
!
WRITE( stdout, &
'( 5X,"ethr = ",1PE9.2,", avg # of iterations =",0PF5.1 )' ) &
ethr, avg_iter
!
! ... deallocate work space
!
DEALLOCATE( becp, becp_ )
DEALLOCATE( s_diag )
DEALLOCATE( h_diag )
!
RETURN
!
END SUBROUTINE c_bands_gamma
!
!
!-----------------------------------------------------------------------
SUBROUTINE c_bands_k()
!-----------------------------------------------------------------------
!
! ... This routine is a driver for the diagonalization routines of the
! ... total Hamiltonian at each k-point.
! ... It reads the Hamiltonian and an initial guess of the wavefunctions
! ... from a file and computes initialization quantities for the
! ... diagonalization routines.
! ... There are three types of iterative diagonalization:
! ... a) Davidson algorithm (all-band)
! ... b) Conjugate Gradient (band-by-band)
! ... c) DIIS algorithm
!
IMPLICIT NONE
!
! ... here the local variables
!
REAL(KIND=DP) :: avg_iter, cg_iter, diis_iter, v_of_0, DSUM, ERF
! average number of iterations
! number of iteration in CG
! number of iteration in DIIS
! the average of the potential
! summation function
! error function
INTEGER :: ik, ig, ibnd, dav_iter, ntry, notconv
! counter on k points
! counter on G vectors
! counter on bands
! number of iterations in Davidson
! number or repeated call to diagonalization in case of non convergence
! number of notconverged elements
INTEGER, ALLOCATABLE :: btype(:)
! type of band: conduction (1) or valence (0)
LOGICAL :: ltest
! .TRUE. if there are too many not converged bands
!
!
IF ( ik_ == nks ) THEN
!
ik_ = 0
!
RETURN
!
END IF
!
! ... allocate arrays
!
ALLOCATE( btype( nbnd ) )
ALLOCATE( h_diag( npwx ) )
ALLOCATE( s_diag( npwx ) )
!
IF ( isolve == 0 ) THEN
!
WRITE( stdout, '(" Davidson diagonalization (with overlap)")')
!
ELSE IF ( isolve == 1 ) THEN
!
WRITE( stdout, '(" Conjugate-gradient style diagonalization")')
!
ELSE IF ( isolve == 2 ) THEN
!
WRITE( stdout, '(" DIIS style diagonalization")')
IF ( ethr > diis_ethr_cg ) &
WRITE( stdout, '(6X,"use conjugate-gradient method ", &
& "until ethr <",1PE9.2)' ) diis_ethr_cg
ELSE
!
CALL errore( 'c_bands', 'isolve not implemented', 1 )
!
END IF
!
avg_iter = 0.D0
!
! ... v_of_0 is (Vloc)(G=0)
!
v_of_0 = DSUM( nrxx, vltot, 1 ) / REAL( nr1 * nr2 * nr3 )
!
#if defined (__PARA)
CALL reduce( 1, v_of_0 )
#endif
!
if ( nks > 1 ) REWIND( iunigk )
!
! ... For each k point diagonalizes the hamiltonian
!
k_loop: DO ik = 1, nks
!
IF ( lsda ) current_spin = isk(ik)
!
! ... Reads the Hamiltonian and the list k+G <-> G of this k point
!
IF ( nks > 1 ) READ( iunigk ) npw, igk
!
! ... do not recalculate k-points if restored from a previous run
!
IF ( ik <= ik_ ) THEN
!
CALL save_in_cbands( iter, ik, dr2 )
!
CYCLE k_loop
!
END IF
!
! ... various initializations
!
IF ( nkb > 0 ) &
CALL init_us_2( npw, igk, xk(1,ik), vkb )
!
! ... read in wavefunctions from the previous iteration
!
IF ( nks > 1 .OR. .NOT. reduce_io ) &
CALL davcio( evc, nwordwfc, iunwfc, ik, -1 )
!
! ... Needed for LDA+U
!
IF ( lda_plus_u ) CALL davcio( swfcatom, nwordatwfc, iunat, ik, -1 )
!
! ... sets the kinetic energy
!
g2kin(1:npw) = ( ( xk(1,ik) + g(1,igk(1:npw)) )**2 + &
( xk(2,ik) + g(2,igk(1:npw)) )**2 + &
( xk(3,ik) + g(3,igk(1:npw)) )**2 ) * tpiba2
!
!
IF ( qcutz > 0.D0 ) THEN
DO ig = 1, npw
g2kin (ig) = g2kin(ig) + qcutz * &
( 1.D0 + ERF( ( g2kin(ig) - ecfixed ) / q2sigma ) )
END DO
END IF
!
IF ( ( isolve == 1 ) .OR. &
( isolve == 2 .AND. ethr > diis_ethr_cg ) ) THEN
!
! ... Conjugate-Gradient diagonalization
! ... and first steps of RMM-DIIS diagonalization
!
! ... h_diag is the precondition matrix
!
h_diag(1:npw) = MAX( 1.D0, g2kin(1:npw) )
!
ntry = 0
!
CG_loop : DO
!
IF ( iter /= 1 .OR. istep /= 1 .OR. ntry > 0 ) THEN
!
CALL cinitcgg( npwx, npw, nbnd, nbnd, evc, evc, et(1,ik) )
!
avg_iter = avg_iter + 1.D0
!
END IF
!
CALL ccgdiagg( npwx, npw, nbnd, evc, et(1,ik), h_diag, ethr, &
max_cg_iter, .not.lscf, notconv, cg_iter )
!
avg_iter = avg_iter + cg_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
!
ltest = .NOT. ( ( ntry <= 5 ) .AND. &
( ( .NOT. lscf .AND. ( notconv > 0 ) ) .OR. &
( lscf .AND. ( notconv > 5 ) ) ) )
!
IF ( ltest ) EXIT CG_loop
!
END DO CG_loop
!
ELSE IF ( isolve == 2 ) THEN
!
! ... when ethr <= diis_ethr_cg start the RMM-DIIS method
!
h_diag(1:npw) = g2kin(1:npw) + v_of_0
!
CALL usnldiag( h_diag, s_diag )
!
ntry = 0
diis_iter = 0.D0
!
btype(:) = 0
!
IF ( iter > 1 ) &
WHERE( wg(:,ik) < 1.0D-4 ) btype(:) = 1
!
RMMDIIS_loop: DO
!
CALL cdiisg( npw, npwx, nbnd, diis_ndim, evc, et(1,ik), ethr, &
btype, notconv, diis_iter, iter )
!
avg_iter = avg_iter + diis_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
!
ltest = .NOT. ( ( ntry <= 5 ) .AND. &
( ( .NOT. lscf .AND. ( notconv > 0 ) ) .OR. &
( lscf .AND. ( notconv > 5 ) ) ) )
!
IF ( ltest ) 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
!
ltest = .NOT. ( ( ntry <= 5 ) .AND. &
( ( .NOT. lscf .AND. ( notconv > 0 ) ) .OR. &
( lscf .AND. ( notconv > 5 ) ) ) )
!
IF ( ltest ) EXIT david_loop
!
END DO david_loop
!
END IF
!
IF ( notconv /= 0 ) &
WRITE( stdout, '(" warning : ",i3," eigenvectors not",&
&" converged after ",i3," attemps")') notconv, ntry
!
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
!
#if defined (__PARA)
CALL poolreduce( 1, avg_iter )
#endif
!
avg_iter = avg_iter / nkstot
!
WRITE( stdout, &
'( 5X,"ethr = ",1PE9.2,", avg # of iterations =",0PF5.1 )' ) &
ethr, avg_iter
!
! ... deallocate work space
!
DEALLOCATE( s_diag )
DEALLOCATE( h_diag )
DEALLOCATE( btype )
!
RETURN
!
END SUBROUTINE c_bands_k
!
END SUBROUTINE c_bands
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