[Wien] Problem with mixer

[Björn Hülsen]

Dear L. Marks,

I investigate the interface between an insulator and a magnetic material, looking for the stable structures 
for different terminations and registries. So there are certainly some "unphysical" configurations in the 
candidate pool. Maybe I can compare the stability of the structures with the number of iteration needed to 
converge them when all calculations finished.

At the moment I try different (smaller) values for the mixer which seem to help a bit.

There are 7500 PW's (from case.outputd*) and around 33000 CLM's (number of lines in case.clmsum*). According 
to your second statement this causes troubles.
Since finally everything converges I would rather wait until the final release of the next version.

Best regards
Bjoern

Laurence Marks wrote:
> I can only suspect a problem at 40 iterations.
> 
> 50-70 is a very large number, and normally convergence takes < 30. The
> default 0.40 in the mixing is a bit greedy, and 0.3 or 0,2 might be
> better. You may also (perhaps more importantly) be incorrectly posing
> the physics or using -it when :DIS is small (which can have some
> problems and lead to poor convergence),
> 
> Do you have a relatively small number of PW's which are > 1D-12
> compared to the number of CLM's? If so I think I know why your
> convergence is slow but you will have to wait until the next release
> unless you are having pathalogical problems and want to test a beta
> version.
> 
> On 10/22/07, Björn Hülsen <huelsen at fhi-berlin.mpg.de> wrote:
>> The error occurred in the 40th iteration.
>> But this problem appears somewhat randomly. I had several (order of 50) other calculations running for 50 - 70
>>   iterations without it.
>>
>> Thank you for the hint.
>>
>> Best regards
>> Bjoern
>>
>> Laurence Marks wrote:
>>> On 10/22/07, Björn Hülsen <huelsen at fhi-berlin.mpg.de> wrote:
>>>> Dear L .Marks,
>>>>
>>>> thanks for the code.
>>>> But, as I wrote in my first email, I used the default input for the mixer with a history setting of 8.
>>>>
>>>> MSEC1  0.0   YES  (BROYD/PRATT, extra charge (+1 for additional e), norm)
>>>> 0.40            mixing FACTOR for BROYD/PRATT scheme
>>>> 1.00  1.00      PW and CLM-scaling factors
>>>> 9999  8         idum, HISTORY
>>>>
>>>> Best regards
>>>> Bjoern
>>>>
>>> I missed that. Did it occur at the 20th iteration, or perhaps the
>>> 40th? If it did I think I know what it is. Unfortunately I cannot
>>> currently reach my cluster to check. As a patch you can remove the
>>> history files (rm *bro*) and run with the option "-r 99999". There is
>>> an obsolete option in the runXX_lapw to reset the mixing after some
>>> number of iterations which should not be there (with the new mixer)
>>> and might be causing problems.
>>>
>> --
>> Björn Hülsen
>> Fritz-Haber-Institute
>> Theory Department
>> Faradayweg 4-6
>> 14195 Berlin
>>
>> phone:  +49 30 8413-4863
>> email:  huelsen at fhi-berlin.mpg.de
>> www:    www.fhi-berlin.mpg.de
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
> 
> 

-- 
Björn Hülsen
Fritz-Haber-Institute
Theory Department
Faradayweg 4-6
14195 Berlin

phone:  +49 30 8413-4863
email:  huelsen at fhi-berlin.mpg.de
www:    www.fhi-berlin.mpg.de