[gate-users]

[Mutanga Theodore]

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

>>>> for the method to work shouldn't it read
/random/resetEngineFrom endOfRun.rndm

Where the endOfRun.rndm is the file copied from the dummy simulation ?

You should also make sure the files are in the same directory as from
where you launch gate. Or better still check the GATE manual.


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