[Pw_forum] parallelization issues

[Mahmoud Payami]

Dear Gabriele and Stefano,

Thank you very much for your explanations.
Bests,
         Mahmoud
 


> It means that since very little communication is needed across different 
> images this parallelization does not suffer much (at all) if the 
> communication network is not very fast... however it does not 
> distribute  the memory and I/O ... which may be bad for the efficiency 
> of the calculation as we are learning these days from the discussion 
> going on on pool parallelization (which also is less-communication and 
> more-memory&I/O intensive than R&G parallelization)...
> My today understanding of this is that one could increase the number of 
> processors using R&G parallelization as far as the network at hand 
> allows to get a good scaling... then one can increase further the number 
> of processors by adding pool parallelization and, in case of  NEB 
> calculations, some image parallelization.
> 
> Hope this helps,
>  Stefano de Gironcoli
> 
> Mahmoud Payami wrote:
>> Dear ALL,
>>  
>> In sec. of "parallelization issues" of UG, is mentioned that: "As a 
>> general rule, image parallelization may give good scaling..."
>> Could anybody please explain what exactly it means in terms of say, 
>> static linking, using more npools, or so.
>>  
>> Bests,
>>            Mahmoud Payami
>> Physics Group, AEOI.
>>  
>>  
>>  
>>  
>>  
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