[Gate-users] "Segmentation violation" aborts my run

[Ida Häggström]

Dear Marcin,
thank you so much for your very thorough reply! I will surely try and find
out about this process 7508. As for point #2, It seems very plausible that
that could cause problems for the system. However, I have already tried
disabling all visualization but I always get the same errors. =( I will try
and find some unix expert that can come have a look at my errors and maybe
tell me the origin. For point #3, I have only simulated back to back 511keV
photons as a first simple case. I figured I'd get that to work, then go via
the positrons... And unfortunately I only have the one computer I'm working
on. I will look into the geometry test errors as well (my other post
"geomTest Error: overlapping daughters and overshooting daughter volume"),
and see if that is connected somehow. Either way, if I manage so solve the
problem I will post the solution! Thank you very much again, I really
appreciate your help!
sincerely,
Ida

2009/9/24 Marcin Balcerzyk <m.balcerzyk at pluri.ucm.es>

>  Dear Ida.
>
>
>
> I am no expert in debugging Gate, but I have three suggestions:
>
>
>
> 1.       Double *check what is the process 7508 doing* (number in your
> description of the problem from 23 Sept.). If this is Gate itself, there is
> no clue, but if any other program – it may be indicative.
>
> 2.       *Disconnect visualization of gamma tracks.* I have seen it once
> in early days of my Gate simulations, that graphic subsystem simply chokes
> at high rate or amount of the events or when there is simply too many. If
> you use 10Bq it does not seem as high activity at all, but… As the problem
> appears only at longer times of simulation, it is rather not the Gate macro
> itself. Note first sensible (to me) message of stacking the trace in your
> debugging message: #5  0x011aaa56 in TUnixSystem::*StackTrace. *All* *else
> seems like very deep Unix system error, distantly related to Gate.
>
> 3.       For the same reason of speed, as in point 2: if you have a
> choice, *try to run the same macro on a significantly slower system*. I
> experienced segmentation violations when positrons did not annihilate on the
> way from the source and did not find any material to react with and escaped.
> On a slow system a few escapes during few tens of minutes of simulation were
> not a problem, Gate could handle this, but on a same Gate version with the
> same macro on a system with 4x the speed, the escaping positrons induced
> rapid segmentation violation.
>
> If anything of that works, let me know. I am just curious.
>
>
>
> Best regards
>
>
>
> Marcin Balcerzyk
>
> Instituto Pluridisciplinar
>
> Universidad Compultense de Madrid
>
> Paseo Juan XXIII n. 1
>
> 28040 Madrid, Spain
>
> tel. +34 91 3943261
>
> fax. +34 91 3943266
>
> movil +34 697 322 126
>
> Skype: balcerzm
>
>
>
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