[CP2K:4460] neb : question about the number of scf optimizations for each band step for each replica

[wolfshow]

Dear All,

I am facing with the similar questions.
In my calculations, if I used NO_LS, the results seem more reasonable (the 
total energy of each image converged). I want to know if there is some 
disadvantageous consequence of using NO_LS in a NEB calculation

Thank you in advance.

Best Regards,

Fengchao


在 2013年5月21日星期二UTC+8上午1时52分23秒，afloris写道：
>
>
>
>
> On Mon, May 20, 2013 at 4:08 PM, Teodoro Laino <teod... at gmail.com<javascript:>
> > wrote:
>
>> DIIS performs a LS - what you see is the result of the line search.
>> Use NO_LS<http://manual.cp2k.org/trunk/CP2K_INPUT/MOTION/BAND/OPTIMIZE_BAND/DIIS.html#list_NO_LS> if 
>> you don't like that.
>>
>>
>
>
> What are the consequences of using NO_LS in a NEB calculation? Using NO_LS 
> would result in a single optimization of the image
> (per band step) and  (maybe separate issue) no electronic optimization at 
> all for "fixed" images?
>
> I am just running a test, with 3-5 replica only.  I see quite a strong 
> dependence on the K_SPRING constant if I vary it from 0.05 to 0.02 
> (the barrier decreases of about 0.05eV and the path is different).  
> Is is correct to expect a much reduced variation of the barrier with 
> K_SPRING, if the number of
> images is increased, e.g. to 10-15? Which distance is typically OK between 
> adiacent images, 0.5 A?
> Thank you for your help
> Best
> Andrea
>
>
>
>  
>
>> Moreover, I have no idea if this is a production run or simply a test, 
>> but you want to keep the distance between your replica much smaller than 
>> 3.0+ Angstrom.
>> Hope this helps.
>> Teo
>>  
>>
> On May 20, 2013, at 1:14 PM, Andrea Floris <an.... at gmail.com<javascript:>> 
>> wrote:
>>
>> Dear Teo, 
>>
>> I attach the input and output and all relevant files. 
>>
>> My problem is in the BAND* files , whose number is indeed equal to the 
>> number of replica (three in my case). 
>> If you in one of these files (prefix is neba) do  
>>
>> grep -i  'Band  Step  Nr.'  neba-BAND1.out
>>
>> you have as output something like
>> ... 
>>  ** Band  Step  Nr. :   13                                               
>>      **
>>  ** Band  Step  Nr. :   13                                               
>>      **
>>  ** Band  Step  Nr. :   13                                               
>>      **
>>  ** Band  Step  Nr. :   13                                               
>>      **
>>  ** Band  Step  Nr. :   13                                               
>>      **
>>  ** Band  Step  Nr. :   14                                               
>>      **
>>  ** Band  Step  Nr. :   14                                               
>>      **
>>  ** Band  Step  Nr. :   14                                               
>>      **
>> ...
>>
>> so, e.g. 5 optimizations (but geometrical or purely electronic scf???) in 
>> the band  step 13, and 3 in the band step 14...
>> That's the point I don't understand...
>>
>>
>> Moreover, I also do not understand why this is done *also* for the end 
>> points, when you choose to not optimize 
>> the initial and final replica...For example in my case here replica 1 was 
>> fixed.  In fact in the 
>>
>> neba-1.ener
>>
>> file, the energy of replica 1 is fixed, i.e. it has always the same 
>> energy through the band optimization steps. But in the file  neba-BAND1.out 
>> many total energies are found...
>> one for each scf optimization.
>>
>> Thanks in advance for you answer,
>>
>> Best
>> Andrea
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Mon, May 20, 2013 at 9:54 AM, Teodoro Laino <teod... at gmail.com<javascript:>
>> > wrote:
>>
>>> >>
>>> >> 1. why  more than one scf optimization is performed? (every 
>>> optimization being achieved with ~40 scf steps)
>>> > it depends on how many processors you are using and how many 
>>> processors per replica you requested. On the top of that, the number of scf 
>>> optimisations depends also on the type of optimiser you are using.
>>> > Again without an input is almost useless to cover all possible things 
>>> you may see.
>>> Correction: forget about the parallel setup - you should always have a 
>>> number of BAND* files equal to the number of frames of your NEB.
>>> So not sure at all what you are seeing… (probably it is only the output 
>>> of the OUTER_SCF cycle)
>>>
>>> In any case, without input..
>>>
>>> >
>>> >> 2. Are these purely electronic optimizations, or there is a 
>>> geometrical minimization involved?
>>> > the geometry optimisation steps are not shown in the *BAND* output
>>> >
>>> > Regards
>>>
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>>>
>>
>>
>> -- 
>>  Dr Andrea Floris
>>  Research Associate
>>  King's College London
>>  Strand, London WC2R 2LS
>>  United Kingdom
>>  Phone: +44 (0) 207 848 2064
>>  Fax    : +44 (0) 207 848 2420
>>  Location:  Strand Building, 4th floor, Room 4.02 
>>  Emails: andr... at kcl.ac.uk <javascript:>, an.... at gmail.com<javascript:> 
>>
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>>  
>> <neb_test_3replicas.tgz>
>>
>>
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>>  
>>
>
>
>
> -- 
>  Dr Andrea Floris
>  Research Associate
>  King's College London
>  Strand, London WC2R 2LS
>  United Kingdom
>  Phone: +44 (0) 207 848 2064
>  Fax    : +44 (0) 207 848 2420
>  Location:  Strand Building, 4th floor, Room 4.02 
>  Emails: andr... at kcl.ac.uk <javascript:>, an.... at gmail.com<javascript:> 
>
>
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