[Carpet] Bugzilla Bug 118

[Erik Schnetter]

On Feb 22, 2008, at 09:00:20, Luca Baiotti wrote:

> Hallo Erik, hallo Thomas, hallo everyone.
>
> Is there any news about Carpet Bugzilla Bug 118 filed by Bela long  
> ago?
>
> I might have encountered it again, in a simulation that ran for a few
> weeks and had performed > 10^5 iterations. The run had recently
> recovered, ~300 iterations before this fatal error:
>
> INFO (CarpetRegrid2): Centre 0 is at position [0,0,0]
> INFO (CarpetRegrid2): Centre 1 is at position [0,0,0]
> INFO (CarpetRegrid2): Centre 2 is at position [0,0,0]
> INFO (CarpetRegrid2): Regridding
> INFO (Carpet): Grid structure statistics:
> INFO (Carpet): GF: rhs: 371k active, 485k owned (+31%), 843k total
> (+74%), 46.9 steps/time
> INFO (Carpet): GF: vars: 85, pts: 263M active, 330M owned (+25%), 568M
> total (+72%), 1.0 comp/proc
> INFO (Carpet): GA: vars: 581, pts: 3M active, 3M total (+0%)
> INFO (Whisky): Setting up the atmosphere mask: all points are  
> not_atmosphere
> INFO (Whisky): Setting up the atmosphere mask: all points are  
> not_atmosphere
> INFO (Whisky): Setting up the atmosphere mask: all points are  
> not_atmosphere
> WARNING level 0 in thorn CarpetLib processor 0 host node0052.admin
>   (line 257 of
> /data1/baiotti/Cactus/configs/belladonna_NoDebug/build/CarpetLib/ 
> gdata.cc):
>   -> Internal error: extrapolation in time.  time=3153
> times=[3153,3152.94,3152.87]

This looks as if there was an accumulation of floating point error.   
This should not happen -- the times of the individual levels should be  
re-synchronised when the levels are aligned in time.  This may not  
happen correctly.

> Actually this might be a different problem. Of course I am producing
> output with verbose=yes, but debug information will require more time,
> since the machines I am using have problems running with DEBUG = yes.
> So I first wanted to know whether there is any new info about this.
>
>
> While I was writing this email, the run with increased verbosity
> finished. You can find the 49Mb output file on belladonna in
> /home/baiotti/tmp


The output file says that there is a core file.  Can you load the core  
file into a debugger and output both "time" and "times" with very high  
accuracy?

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>   http://www.cct.lsu.edu/~eschnett/

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