[Pw_forum] Parallel scf calculations

[MKondrin]

Francesco Pelizza wrote:
> 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
>
>
It depends on how your version  was compiled and linked (Quantum 
Espresso allows both serial and parallel versions).  To enable parallel 
version QE should be linked with appropriate MPI libraries. You might 
contact your system administrator for more information. In theory there 
is not much difference between serial and parallel execution (both give 
right answers) however the latter somewhat faster (not much because the 
problem is not massively parallel). May be your colleagues just did not 
pay attention to the multiple output in the output file?

Best regards,

M. V. Kondrin