Dear Filipe,
I appreciate your reply. It is so helpful for me.
Best Regards
JWY
2014-04-23
yjunwei2012
????Filipe Camargo Dalmatti Alves Lima <flima at if.usp.br>
?????2014-04-23 10:59
???Re: [Pw_forum] The relax problem
????"PWSCF Forum"<pw_forum at pwscf.org>
???
By looking at the total forces. There is a part in the output that will show
the forces on the atoms and the total force of the system.
You can grep the output using this command: cat $youroutput | grep "total
force" (or something like that, I don't remember the captcha exactly). This
number should decrease along the time. If the total force reach the threshold
condition, the calculation will stop. Otherwise it can also stop after lots of
tries and it will complain saying that the convergence didn't achieved the
mininum.
For further info, the criteria for the force can be seen below:
etot_conv_thr REAL
Default: 1.0D-4
convergence threshold on total energy (a.u) for ionic
minimization: the convergence criterion is satisfied
when the total energy changes less than etot_conv_thr
between two consecutive scf steps. Note that etot_conv_thr
is extensive, like the total energy.
See also forc_conv_thr - both criteria must be satisfied
forc_conv_thr REAL
Default: 1.0D-3
convergence threshold on forces (a.u) for ionic minimization:
the convergence criterion is satisfied when all components of
all forces are smaller than forc_conv_thr.
See also etot_conv_thr (note that the latter is extensive,
forc_conv_thr is not) - both criteria must be satisfied
source:
http://www.quantum-espresso.org/wp-content/uploads/Doc/INPUT_PW.html#id3119460
Regards,
Filipe
On Tue, Apr 22, 2014 at 10:04 PM, yjunwei2012 <yjunwei2012 at 163.com> wrote:
Dear manchugh?
Thank you for your reply! I still have some problems and need your help.
When we relax the system, how can we judge the relax result is successful or
fail? and is there have some big different aspects between relax and vc-relax?
Thank you again!
Best wishes!
JWY
2014-04-23
yjunwei2012
????manchugh at iitk.ac.in
?????2014-04-23 05:04
???Re: [Pw_forum] The relax problem
????"PWSCF Forum"<pw_forum at pwscf.org>
???
Dear JWY
Your output file still has the same number of atoms. There is no problem
with your system. You can see the missing atoms in the image you sent by
using "Number of units drawn" option in Modify tab of xcrysden.
Thank you
Manjusha
Ph.D student
IIT Kanpur
India
> Hello dear QE users,
> I have used the 'calculation=relax' to calculation a 48 atomes' system,
> and I compare the structure data(after relax) with the one from input
> file(before relax),I find that there has a big difference. Then I
> import the two structures to Xcrysden, the result as the above two
> pictures show that, I do not understand why and wonder if some problems
> with symmetry? I am not sure.
> I look forward to your suggestion! Thank you!
>
> Best wishes!
> JWY
>
> 2014-04-22
>
>
>
> yjunwei2012_______________________________________________
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--
_________________________________________
Filipe Camargo Dalmatti Alves Lima
PhD Student
University of S?o Paulo, Physics Institute, Materials Physics Department,
Nanomol Group, Brazil.
Phones: (11) 3091-6881 (USP)
(11) 97408-2755 (Vivo)
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