[Pw_forum] Parallel scf calculations

[Francesco Pelizza]

Hi dear Kondrin

I do not have nothing as you suggested wrote in my output file

At this point is not clear to me what i have to do to be able to run 
pw.x in parallel calculations

many of my colleagues just installed OpenMpi and used the below commands 
i firstly wrote:

mpirun -np 4 ~/Software/espresso-5.1/bin/pw.x -ni2 -nk2 -i pvdf.scf.in >pvdf.scf.out

without doing anything on the already installed QE, so i do not know what is missing

Where can i find useful information about this topic?

Or, Can you give me some suggestion?

Cheers

Wish you a nice weekend

Francesco




Il 14/02/2015 12:57, MKondrin ha scritto:
> Francesco Pelizza wrote:
>> Hello Dear Paolo and co-workers,
>>
>> I am having some difficulties in obtaining output file when I run
>> parallel calculation with scf (pw.x).
>>
>> Using OpenMPI, I used these commands:
>> mpirun -np 4 ~/Software/espresso-5.1/bin/pw.x -ni2 -nk2 -i pvdf.scf.in
>>   >pvdf.scf.out
>> mpirun -np 4 ~/Software/espresso-5.1/bin/pw.x -i pvdf.scf.in >pvdf.scf.out
>>
>>
>> and the calculation works but the problem is the output file, where
>> everything is written many times, the same number of times of the number
>> of processors i've been used, so if i use 4 processor the output file
>> data are written 4 times, if i use 3 processors the data are written in
>> the same output file 3 times and so on
>> and everything in the output file became FUZZY
>>
>> grep or awk command give multiple data instead of only once per
>> simulation, it prints me many data as the same amount of processors i use
>>
>> I had the same problem with the input file with this synthax:
>> mpirun -np 4 ~/Software/espresso-5.1/bin/pw.x -ni2 -nk2 < pvdf.scf.in
>>   >pvdf.scf.out
>>
>> I solved the problem for the input file with this synthax:
>> mpirun -np 4 ~/Software/espresso-5.1/bin/pw.x -ni2 -nk2 -i pvdf.scf.in
>>   >pvdf.scf.out
>>
>> This synthax doesn't solve the problem:
>> mpirun -np 4 ~/Software/espresso-5.1/bin/pw.x -ni2 -nk2 -i pvdf.scf.in
>> -o pvdf.scf.out
>>
>>
>> So now the input file is written only once (avoiding problems during the
>> reading), but i do not know how to solve the problem witht the output
>> file tha tis still written many times instead of only once
>>
>> I am not finding anywhere a complete list of argument i can use in
>> pw.x......
>>
>> Can you help me?
>>
>> Best wishes
>>
>> Sincerly
>>
>> Francesco Pelizza
>>
>>
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>>
>>    
> Did you really use parallel version of pw.x? If so you should have in
> the beginning of output file something like:
>
>    Parallel version (MPI), running on    64 processors
>       K-points division:     npool     =    8
>       R & G space division:  proc/pool =    8
>
> Your problems looks like your having serial  copies of the pw.x launched
> on different nodes  and each  of them  overwriting the same output file.
>
> Best regards,
>
> M. V. Kondrin (High Pressure Physics Institute RAS, Troitsk, Russia)
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