[Wien] force optimization with MSR1a

[shamik chakrabarti]

Dear Prof. Blaha Sir & wien2k users,

                                        In continuation with previous mails
I want to further inform that after 85 iterations energy is already
converged & the display is saying that MSR1a in case.inm has been changed
to MSR1 and that the process will only converge the charge-density now.
However, on some atoms the force :FR is still more than 200 mRy/a.u.

Then what about the force convergence?

Any response regarding this is eagerly awaited.

Thanking you,

with regards,


On Thu, Aug 28, 2014 at 5:31 PM, shamik chakrabarti <shamikphy at gmail.com>
wrote:

> Dera Prof. Blaha Sir,
>
>                 Thank you very much for your reply. It is indeed very
> helpful. Yes energy convergence has been reached up to ~ 0.001 so far. Also
> E-tot & FR is decreasing. We are using 14 k-points for a 56 atomic cell.
> However, there is one doubt...the material is found to be in semiconducting
> range with a band gap of ~3 eV. Do you think for such a high band-gap
> material 80 iterations may not be much &  should we wait?
>
> Thanks in advance.
>
> with regards,
>
>
> On Thu, Aug 28, 2014 at 3:22 PM, Peter Blaha <pblaha at theochem.tuwien.ac.at
> > wrote:
>
>> 80 iterations for a more complicated MSR1a optimization is NOT much. I
>> often need a couple of 100 iterations for a big (metallic and magnetic)
>> system with 3d elements.
>>
>> However, make sure:
>>
>> grep :DIS case.scf is showing a "reasonable" convergence" (eg. it should
>> not stay long above 1.0)
>> grep :ENE case.scf   shows a trend that E-tot is reducing (not
>> necessarily monotonically, but overall .
>> grep :FR case.scf   is decreasing (overall).
>>
>> If these criteria are fulfilled, continue.
>>
>> If not, you may have started very poorly ?? or you should use a better
>> k-mesh or TEMP+smearing, or your RMT,... is bad ....
>>
>>
>>
>> On 08/28/2014 10:46 AM, shamik chakrabarti wrote:
>>
>>>
>>> Dear wien2k users,
>>>
>>>                         We are doing force minimization of a spinel
>>> compound using MSR1a. After even 80 iterations, force on some atoms are
>>> 200 mRy/a.u. while on some atoms it is ~ 7 mRy/a.u. We are using a
>>> mixing grid of default 0.2 in case.inm.
>>>
>>> My query is that should we change this grid to say at 0.5 for speeding
>>> up the process or will that change eventually sets some undesirable
>>> oscillations in the calculation?....or should we just wait with all
>>> default values as long as the force will not come below 5
>>> mRy/a.u.?....or is their any prescription for optimizing the process to
>>> get correct output in real time scale?
>>>
>>> Thanks in advance,
>>>
>>> with regards,
>>> --
>>> Shamik Chakrabarti
>>> Senior Research Fellow
>>> Dept. of Physics & Meteorology
>>> Material Processing & Solid State Ionics Lab
>>> IIT Kharagpur
>>> Kharagpur 721302
>>> INDIA
>>>
>>>
>>> _______________________________________________
>>> Wien mailing list
>>> Wien at zeus.theochem.tuwien.ac.at
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>>> wien at zeus.theochem.tuwien.ac.at/index.html
>>>
>>>
>> --
>>
>>                                       P.Blaha
>> ------------------------------------------------------------
>> --------------
>> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
>> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
>> Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/
>> theochem/
>> ------------------------------------------------------------
>> --------------
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>>
>
>
>
> --
> Shamik Chakrabarti
> Senior Research Fellow
> Dept. of Physics & Meteorology
> Material Processing & Solid State Ionics Lab
> IIT Kharagpur
> Kharagpur 721302
> INDIA
>



-- 
Shamik Chakrabarti
Senior Research Fellow
Dept. of Physics & Meteorology
Material Processing & Solid State Ionics Lab
IIT Kharagpur
Kharagpur 721302
INDIA
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