[Pw_forum] Relaxation says max steps reached despite changing nsteps

[mohnish pandey]

Dear Alejandro,

Changing ionic relaxation steps of scf steps won't help if you are far from
convergence. Your system has convergence problem. So you need to change the
parameters which have effect on convergence. You can decrease the mixing
parameter beta, or play with smearing. They may help you to reach
convergence.


On Wed, Apr 10, 2013 at 3:55 PM, Alejandro Suarez <
al.suarez.ctr at nrl.navy.mil> wrote:

> Hello,
>
> In my relaxation calculation, my job always finishes with the following
> lines:
> ------------
>   The maximum number of steps has been reached.
>
>       End of BFGS Geometry Optimization
> Begin final coordinates
> ...
> --------------
> To remedy this, I changed nstep to and electron_maxstep to 999 in my
> input file, however the failure continues.
> This happens both in a restarted calculation or when the calculation is
> redone from scratch (and the save files are deleted).
>
> Here is a copy of my input file:
> ------------------
> &control
>      calculation='relax',
>      restart_mode='from_scratch',
>      prefix='4-BN-Gr',
>      pseudo_dir = '../pseudos',
>      outdir='../save',
>      etot_conv_thr = 1.0D-5
>      forc_conv_thr = 1.0D-4
>      tefield=.true.
>      dipfield=.true.
>      nstep = 999,
>   /
>   &system
>      ibrav=  4,
>      A=2.44624, C=33.0,
>      nat=  10, ntyp= 3,
>      ecutwfc = 45.0,
>      ecutrho = 300.0,
>      occupations='smearing',
>      degauss = 0.005
>
>
>      edir=3,
>      emaxpos=0.696
>      eopreg=0.045
>      eamp=0
>   /
>   &electrons
>    conv_thr = 1.0D-8,
>    electron_maxstep = 999
>   /
>   &ions
>   /
> ATOMIC_SPECIES
>   B 10.81   B.pz-n-kjpaw_psl.0.1.UPF
>   C 12.01   C.pz-n-kjpaw_psl.0.1.UPF
>   N 14.007  N.pz-n-kjpaw_psl.0.1.UPF
>
> ATOMIC_POSITIONS crystal
>   B  0.666666667       0.333333333       0.000000000 0 0 0
>   N  0.333333333       0.666666667       0.000000000 0 0 0
>   N  0.666666667       0.333333333       0.098182000
>   B  0.333333333       0.666666667       0.098182000
>   B  0.666666667       0.333333333       0.196364000
>   N  0.333333333       0.666666667       0.196364000
>   N  0.666666667       0.333333333       0.294545000
>   B  0.333333333       0.666666667       0.294545000
>   C  0.333333333       0.666666667       0.391818000
>   C  0.666666667       0.333333333       0.391818000
> K_POINTS {automatic}
> 10 10 1 0 0 0
> --------------------
>
> Any help would be greatly appreciated.
>
> Thank you,
>
> --
>
> Alejandro Suarez
> NRC Research Associate
> Naval Research Laboratory, Code 6877
> 4555 Overlook Ave., SW
> Washington, DC 20375
> Phone: (202) 404-4635
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>



-- 
Regards,
MOHNISH,
-----------------------------------------------------------------
Mohnish Pandey,
PhD Student,
Center for Atomic Scale Materials Design,
Department of Physics,
Technical University of Denmark
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