[gate-users] Random seed

[Angela M K Foudray]

Martin,

Let me make sure that I have this straight - you want to know how to
control whether or not you have the same events happening within a study
- it looks like you are both trying to have the same events to simulate
the system with two sets of detectors, but you also then want to know
how to change the seed so that you can run many iterations of this same
system?

Ange

On Tue, 2005-06-28 at 15:00 -0500, janecekm at mir.wustl.edu wrote:
> Hello GATE users, 
> We are having trouble with the random seed in GATE. We are developing
> a PET system with two different detectors, and we therefore run GATE
> twice with the same seed. The first time we attach detector type #1 as
> crystalSD, and detector type #2 as phantomSD, and in the second run
> - with the same seed - we switch the crystalSD and phantomSD for the
> detectors. This produces two output (singles) files which we later
> sort into sinograms. 
> This approach is working with the exception of producing original data
> in different runs. If we subtract sinograms from two different runs
> (with different seeds) from each other, it turns out that all events,
> except for a few hundred, are identical. 
>  
> We have tried several different approaches to getting original
> data. One approach is running a short dummy program, and copying the
> endOfRun.rndm file onto our random-file and then running GATE (both
> times) with : 
> /gate/output/root/setSaveRndmFlag 0 
> /random/resetEngineFrom beginOfRunDummy.rndm 
> 
> We have also tried setting "/gate/output/root/setSaveRndmFlag 1" for
> the first run, and copying beginOfRun.rndm onto our random file for
> the second simulation, but that doesn't produce correlated data. 
> Does anybody have an idea of how to solve this problem? 
> Sincerely, 
> Martin Janecek 
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-- 
Angela M K Foudray <afoudray at stanford.edu>