[Pw_forum] a question about a calculation on a relatively large system

[degironc]

What happens if you restart the calculation (restart_mode='restart' in 
&CONTROL namelist) ?
does it go on or does it stop at the same point ?
stefano

Peter Winey wrote:

> Dear all,
>  
> I am trying to do a structural relaxation on a relatively large 
> system, which
> has 240 atoms in one unit cell.
>  
> I know it may sound crazy, but the crystal contains only C and H atoms,
> so I thought that my cluster might be able to handle it.
>  
> Indeed, I was able to run pwscf structural relaxation calculations. 
> The 1st
> iteration finished ok. However, at the end of the 2nd iteration (which 
> also
> finished ok), after the program printed out:
> ------------------------------------------
> ...
> number of scf cycles = 2
> number of bfgs steps = 1
> energy old =  - 2084.xxx
> energy new = - 2086.xxx
> CASE: energy_new < energy_old
> ------------------------------------------
> The run stopped without giving any information expect saying that "mpi
> stopped without calling mpi_finalize" or sth like that.
>  
> I repeated the calculation and it always stopped at the same place. 
> It is wierd since I had no problem before when running smaller systems
> (say, 150 atoms).
>  
> Could some one give me a hint on what could be the reason? Is it related
> to the system size? If so, I have no idea why the pw.x program is able to
> finish the first and the second iteration, but does not continue...
>  
> Thanks in advance for any suggestions that you may have!
>
> -Peter
>
> ********************************************
> Peter Winey, Ph.D., DuPont
> peterwiney at gmail.com <mailto:peterwiney at gmail.com>
> ********************************************