[CP2K-user] NEB - number of replicas

[Matt W]

Hi,

sorry you didn't get a reply, we normally try to.

I haven't checked this, but I believe that the NUMBER_OF_REPLICA keyword is 
used for start up and tells CP2K how many _intermediate_ images to create, 
filling in any not given explicitly using interpolation. So if you set it 
to 6 and only provide initital and final coordinates there will be 8 images 
running - beginning and end + NUMBER_OF_REPLICA intermediates.

Matt

On Monday, February 18, 2019 at 10:36:15 AM UTC, tobias... at gmail.com 
wrote:
>
> Hi, Sorry I did not get an answer to the issue so far, and I did not work 
> on it to figure the problem out.
> But I would be really happy, if someone else could find a suitable answer 
> to the problem.
> Let me know, if you are more successful.
>
> Best wishes and good luck
> Tobias
>
>
> Am Donnerstag, 25. Oktober 2018 14:18:04 UTC+2 schrieb 
> tobias... at gmail.com:
>>
>> Dear all,
>>
>> I want to perform a nudged elastic band (NEB) calculation using cp2k.
>> I get the "CPASSERT failed", when I try to calculate too many replica at 
>> once.
>> Does anyone know the difference between the "Number of Images" and 
>> "Number of Replicas"?
>> Does anyone have experience, how to choose the number of processors per 
>> replica NPROC_REP  and the number of calculated replica  
>> NUMBER_OF_REPLICA   
>> for the best performance? 
>> Is there a thump rule, how many Open MP threads to use for best 
>> performance?
>>
>> I tried to match the total cpu cores with nproc_rep * number_of_replica 
>> but the number_of_replica input seems to be ignored, instead cp2k uses the 
>> number of intermediate structures (replicas) as number of images.
>>
>> When I use 6 replicas and 12 nproc_rep the calculation runs on the 72 
>> core node.
>> however I set the number of replicas to 6 and provided 6 structures. CP2k 
>> now gives as output:
>>
>> Number of Images :            6 **
>>  **  ##     ## ######### ##  #### ##     ##   Number of 
>> Replicas:           1 **
>>  **  ##     ## ##     ## ##   ### ##     ##   Number of 
>> Procs/Rep:         12
>>
>> Why does it change the number of replicas during the run?
>>
>> When I use 9 replicas and 8 nproc_rep the calculation does not run, but 
>> as far as I understand the input should work this way.
>>
>> Best wishes 
>> Tobias
>>
>
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