[Pw_forum] Problem

[Chao Cao]

Hi, 
Thanks for reply. But does this part of the manual actually apply
here? Coz the program actually didn't crash, it was running but doing wierd 
stuff without any output. I tried to make it write to the screen, however, 
it turns out to be exactly the same situation. The output stopped after 
certain steps, and the program was still executing.


Best wishes,

Chao Cao

On Thu, 9 Dec 2004, Paolo Giannozzi wrote:

> On Wednesday 08 December 2004 18:38, Chao Cao wrote:
> 
> > I guess what you mean is the program just got stalled,
> > without any error, output whatsoever, am I right?
> 
> the following items in the manual:
> ----------------------------------
> - pw.x crashes with no error message at all.
> 
> This happens quite often in parallel execution, or under a batch
> queue, or if you are writing the output to a file.
> When the program crashes, part of the output, including the error
> message, may be lost, or hidden into error files where nobody looks
> into. It is the fault of the operating system, not of the code.
> Try to run interactively and to write to the screen.
> ----------------------------------
> [ it may also be useful to #define DEBUG in startup.f90: all processes 
>   will write their output to file ] and:
> ----------------------------------
> - pw.x runs but nothing happens.
> 
> Possible reasons:
>  -in parallel execution, the code died on just one processor.
>     Unpredictable behavior may follow.
>  -in serial execution, the code encountered a floating-point error
>     and goes on producing NaN's (Not a Number) forever unless
>     exception handling is on (and usually it isn't).
> ----------------------------------
> [ actually the second point may also happen in parallel execution ] 
> apply to this case as well
> 
> > It seems that this problem is actually related with MPI, and, somehow 
> > with the library you used. I tried to use a serial version of pw, and it
> > runs  OK. Furthermore, if I abandon MKL, it also runs without stalled.
> 
> it looks like a problem with linear algebra routines
> 
> Paolo
> 
> -- 
> Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
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