[Wien] force optimization with MSR1a

[Peter Blaha]

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
>
>
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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