<div dir="ltr">Dear PWSCF users,<br>       I turn on the 'tefield' option to relax an isolated slab system in the presence of external electric field. The input file is attached below. I use 'bfgs' for the ionic dynamics. However I always got the following error: 'bfgs history already reset at previous step'. Why 'bfgs' method does not work for this 'sawlike' electric field? Shall I change some parameters?<br>
      Thank you very much.<br><br>Hanghui Chen<br>Department of Physics,<br>Yale University<br> <br>&CONTROL<br>  calculation='relax'<br>  wf_collect=.true.<br>  pseudo_dir = './psp'<br>  outdir='/home1/hc336/scratch'<br>
  wfcdir='/home1/hc336/scratch'<br>  prefix='STO-efield-r-E0.01'  <br>  tprnfor = .true.<br>  tstress = .true.<br>  disk_io='low'<br>  verbosity='high'<br>  dt=80.D0<br>  tefield=.true.<br>
/<br>&SYSTEM   <br>  ibrav=  6<br>  celldm(1) = 7.02<br>  celldm(3) = 5.0<br>  nat=  8<br>  ntyp= 3<br>  ecutwfc = 30.0<br>  ecutrho = 180.0<br>  occupations='smearing'<br>  smearing=gauss<br>  degauss=0.005<br>
  edir=3<br>  emaxpos=0.8<br>  eopreg=0.2<br>  eamp=0.01<br>/<br>&ELECTRONS<br>  diagonalization='david'<br>  mixing_beta = 0.7D0<br>  diago_david_ndim = 4<br>  startingwfc='atomic'<br>  startingpot='atomic'<br>
  conv_thr = 1.0d-8<br>/<br>&IONS<br>  ion_dynamics = 'bfgs'<br>  phase_space = 'full'<br>  pot_extrapolation = 'second_order'<br>  wfc_extrapolation = 'second_order'<br>/<br>&CELL<br>
  cell_dynamics = 'damp-w'<br>/<br>ATOMIC_SPECIES<br> Sr  87.62   038-Sr-ca-sp-vgrp.uspp.format.UPF<br> Ti  47.90   022-Ti-ca-sp-vgrp.uspp.format.UPF<br> O   16.00   008-O-ca--vgrp.uspp.format.UPF<br>ATOMIC_POSITIONS alat<br>
 Ti 0.50 0.50 0.50<br> O  0.00 0.50 0.50<br> O  0.50 0.00 0.50<br> Sr 0.00 0.00 1.00 <br> O  0.50 0.50 1.00<br> Ti 0.50 0.50 1.50<br> O  0.00 0.50 1.50<br> O  0.50 0.00 1.50<br>K_POINTS {automatic}<br>10 10 1 0 0 0<br></div>