[Pw_forum] parallel for single k point calculation

[Mahmoud Payami]

Dear Carlo,

Thank you very much for your clear explanation of different kinds of 
paralellizations.
I checked the first case and it works.
Thank you again.
Mahmoud


> Dear Mahmoud Payami,
>
> of course you can.
>
> If you run the parallel version of the program on N cpus, the code will
> distribute the plane waves among the processors (this is called R&G
> parallelization) so that both the memory and workload are distributed.
> This is done automatically.
>
> When you have k points and you want to parallelize also on k points, you
> must run your job with the option -npool NK, where NK is some number
> smaller than the total number of k-points and smaller than the number of
> cpus.
>
> Here some exaples, where I suppose that your job has 10 k-points. When
> you have just 1 k-point (for example gamma), the case 1 is the only
> possibility. Whenever possible a balance of the two parallelizations
> (case 2) gives the best speedup.
>
> 1) without k-points (only R&G):
>
>  mpirun -np 10 pw.x -in input > output
>
>
> 2) with k-points (10) and R&G :
>
>  mpirun -np 10 pw.x -npool 2 -in input > output
>
>
> 3) with k-points (10) only (no R&G):
>
>  mpirun -np 10 pw.x -npool 10 -in input > output
>
>
> Best,
>
> carlo sbraccia
>
>
> Mahmoud Payami wrote:
>> Dear All,
>>
>> How can I run pw.x for a single k point in parallel? Is it possible?
>> Thanks in advance.
>>
>> Mahmoud Payami
>>
>
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