[Pw_forum] questions on vc-relax

[Guoying Gao]

 Dear Axel,
   I'm sorry for my ambiguous esperssions. I mean that in the process
 of relaxing, either "etot_conv_thr" or "forc_con_thr"  ( or both )
 does not converge. I have attached my input and output files(in the accessory).

 Another question:
 >>first of all, you have to make sure that your stress tensor is
 >>reasonably converged with respect to the basis set
How to judge that stress tensor converges with respect to the basis set.


The following is my input files:

&control
    calculation='vc-relax',
    restart_mode='from_scratch',
    dt=30,
    prefix='n2',
    pseudo_dir = '/home/cpmd/yanming/ggy/pseudo/',
    outdir='/home/cpmd/yanming/ggy/tmp/tmp0/',
    tstress=.t.,
    tprnfor=.t.,
    nstep= 100
 /
 &system
   ibrav=  8, celldm(1) =7.85937,celldm(2)=0.66482327482567924981,
   celldm(3)=1.21158932435681654243,
   nat=  8, ntyp= 1,ecutwfc =30, ecutrho=300, nosym = .t.
 /
 &electrons
    mixing_beta = 0.7
    conv_thr =  1.0d-8
 /
 &IONS
    ion_dynamics = 'damp'
    upscale = 20
 /
 &CELL
    cell_dynamics = 'damp-pr'
    press =800
 /
ATOMIC_SPECIES
N  14.0067  N.pbe-van_ak.UPF
ATOMIC_POSITIONS {crystal}
N     0.39750000   0.86660000   0.19890000
N     0.92010000   0.64090000   0.05920000
N     0.60250000   0.13340000   0.69890000
N     0.07990000   0.35910000   0.55920000
N     0.60250000   0.86660000   0.30110000
N     0.07990000   0.64090000   0.44080000
N     0.39750000   0.13340000   0.80110000
N     0.92010000   0.35910000  -0.05920000
K_POINTS { automatic }
5 8 4 0 0 0

Thank you again!
gao