[Pw_forum] DOS in parallel mode

[Goranka Bilalbegovic]

Cyrille Barreteau wrote:

>I know that the dos.x (and other post processing codes) are
>not available in parallel mode. However is it possible to
>obtain the file.pun with pw.x (nscf calculation) in parallel mode and
>use this file.pun to obtain the dos in serial mode with dos.x.
>I have tried this but the code stops with the error
>
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>     from read_file : error #       154
>     reading eigenvalues
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>     stopping ...
>
>
>Does it mean this is not possible, or did I make a mistake?
>  
>
Hello Cyrille,

Although it is true that many postprocessing routines do not run in the 
parallel mode, according to the example 8 ("shows how to use pw.x and 
dos.x to calculate the Density of States of Ni"),  dos.x  runs in parallel:
$PARA_PREFIX $PW_ROOT/bin/dos.x $PARA_POSTFIX < ni.dos2.in > ni.dos2.out

However,  I was  using dos.x  last year (old versions of PWscf) together 
with some tricks.

On old SGI O2K I had a line as (please note that there is no < for input 
file, pw.x ran on the same number of processors):
mpirun -np 2 dos.x -npool 1 inp.dos.in > inp.dos.out

On the Linux cluster (pw.x ran on several processors):
mpirun -np 1 dos.x -npool 1 < inp.dos.in > inp.dos.out


Best regards,
Goranka