[gate-users] How to make uncorrelated random number seeds?

Fri Dec 17 18:08:11 CET 2004

Hello There,

Please refer to some of the posts I made earlier. I solved this by making
a mock simulation with a very weak source like 10Bq or even less. Then I
made a script that runs this simulation say 100 times (four times in your
case), in each instance, I get the file endOfrun.rndm , rename it to
status00i.rndm where i goes from 1 - 100 or whatever number of randoms you
want to generate. ( in your case four maybe)
Then use this status00i.rndm files and force your simulations to use them
by using the comand /random/resetEngineFrom .

Atleast with this method you have different seeds to begin your
simulations with, however if they are uncorrleted or not is another issue,
I made a post about using this method but no one commented about it so Im
using it for now and Im getting some results

hope this helps

Cheers

Theo

 Hello All,
>
> I have read all of your previous discussions on controlling the random
> number seed to ensure that
> each run is independant and have tried to follow these instructions to
> only
> have my system perform
> four identical runs.
>
> I am running 4 parallel simulations each at different time intervals of
> GATE
> on my dual processor machine.  I have dedicated a separate folder to each
> simulation within which i have placed beginOfRun.rndm,  endOFRun.rndm, the
> macro file, and the GATE executable.
>
> In each copy of my macro file I have the following code:
>
> /gate/output/root/enable
> /gate/output/rootsetSaveRndmFlag 1
> /random/setSavingFlag 1
>
> In my output, I find the exact same event numbers in each of the four hits
> files, the only difference is the time of each event, which are just
> offset
> by the starting point of the interval for that run.
>
> This is disconcerting, since I have run several simulations only to
> recently
> discover that none of them are really admissable.
>
> You help is always appreciated.
>
> Ananth Ravi
>
>
> ----- Original Message -----
> From: <gate-users-request at lphe1pet1.epfl.ch>
> To: <gate-users at lphe1pet1.epfl.ch>
> Sent: Friday, December 17, 2004 6:00 AM
> Subject: gate-users Digest, Vol 9, Issue 16
>
>
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>>
>> Today's Topics:
>>
>>    1. Re: ring diameter (Claude Comtat)
>>    2. (pas de sujet) (Sebastien JAN)
>>    3. Derenzo phantom (Jin Zhang)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Thu, 16 Dec 2004 13:40:36 +0100
>> From: Claude Comtat <comtat at ieee.org>
>> Subject: Re: [gate-users] ring diameter
>> To: GATE feedback and helpline for Users
>> <gate-users at lphe1pet1.epfl.ch>
>> Message-ID: <41C18244.5040000 at ieee.org>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>>
>>
>> Mutanga Theodore wrote:
>>
>> > I also found out that the axial sampling interval is 1/2*axial pitch
>> ???
>> > Am I right ?
>>
>>
>> Yes
>>
>>
>> Claude
>>
>>
>> --
>> Claude Comtat comtat at ieee.org
>> Image acquisition and processing group tel: +33 1 69 86 77 02
>> Frederic Joliot Hospital Facility fax: +33 1 69 86 77 49
>> French Atomic Energy Commission www-dsv.cea.fr/shfj
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Thu, 16 Dec 2004 16:41:58 +0100
>> From: Sebastien JAN <jan at shfj.cea.fr>
>> Subject: [gate-users] (pas de sujet)
>> To: GATE feedback and helpline for Users
>> <gate-users at lphe1pet1.epfl.ch>
>> Message-ID: <41C1ACC6.5010304 at shfj.cea.fr>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>>
>>  From Els Wieers :
>> -----------------------
>>
>> Dear gaters,
>>
>> I'm trying to build the geometry of the ClearPET scanner of Brussels.
>> Up to the building of the cassettes everything goes ok. These cassettes
>> should be repeated along  a ring repeater and the second, the fourth,
>> the sixth, ... copy should be shifted along the z-axis over a distance
>> of 5 mm compared to the first, third, fifth, .. copy.
>>
>> So I used the following commands
>>
>> /gate/cassette/repeaters/insert ring
>> /gate/cassette/ring/setRepeatNumber 20
>> /gate/cassette/ring/setModuloNumber 2
>> /gate/cassette/ring/setZshift1 -2.5 mm
>> /gate/cassette/ring/setZshift2 +2.5 mm
>>
>> Unfortunately when I compile, I get the following messages:
>> /gate/cassette/repeaters/insert ring
>> /vis/scene/notifyHandlers scene-0
>> /gate/cassette/ring/setRepeatNumber 20
>> /vis/scene/notifyHandlers scene-0
>> /gate/cassette/ring/setModuloNumber 2
>> ***** COMMAND NOT FOUND </gate/cassette/ring/setModuloNumber 2> *****
>> ***** Command ignored *****
>> /gate/cassette/ring/setZshift1 -2.5 mm
>> ***** COMMAND NOT FOUND </gate/cassette/ring/setZshift1 -2.5 mm> *****
>> ***** Command ignored *****
>> /gate/cassette/ring/setZshift2 +2.5 mm
>> ***** COMMAND NOT FOUND </gate/cassette/ring/setZshift2 +2.5 mm> *****
>> ***** Command ignored *****
>>
>> I do not understand since I used the exact commands as the one used in
>> the usersguide page 32.
>> Can somebody tell me if what is wrong? Is this function out of Gate? And
>> if so, how can I get this shift?
>>
>> Greets
>> Els
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Thu, 16 Dec 2004 17:35:32 -0800
>> From: Jin Zhang <jinzhang at stanford.edu>
>> Subject: [gate-users] Derenzo phantom
>> To: GATE feedback and helpline for Users
>> <gate-users at lphe1pet1.epfl.ch>
>> Message-ID: <41C237E4.4030505 at stanford.edu>
>> Content-Type: text/plain; charset=us-ascii; format=flowed
>>
>> Hi guys:
>>
>> Is there any better way to generate a Derenzo phantom with about 100
>> sphere sources totally with different diameters? Or I have to create
>> them one by one manully? It's easily got messed-up on the positions of
>> the sources.
>>
>> Thanks a lot,
>>
>> Jin Zhang
>>
>>
>> ------------------------------
>>
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>> End of gate-users Digest, Vol 9, Issue 16
>> *****************************************
>>
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