[Pw_forum] Parallel scf calculations

[Francesco Pelizza]

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