[gate-users] uncorrelated random number seeds

[Hiroshi Watabe]

Dear Dirk,

Thank you for your quick response.

Although my generated seed files contain totally different numbers (only
first line of all files is same as 9876), it is not guarantee for the
independencies of these files, isn't it?

I will try simulations with your seeds.

regards,

Hiroshi

 From: Dirk Kruecker <d.kruecker at fz-juelich.de>
Subject: Re: [gate-users] uncorrelated random number seeds
Date: Mon, 17 Oct 2005 10:36:46 +0200
Message-ID: <200510171036.46083.d.kruecker at fz-juelich.de>

> Dear Hiroshi
> 
> the method  Mutanga Theodore described does not create independent random 
> seeds but in most cases this should not be a real problem.  Maybe there is 
> some other reason for your results but it is difficult to say what the reason 
> is for the correlations you see. I posted a detailed explaination how to 
> handle the random files on this list at Jun 30, 2005. I also include a set of 
> random seed files that are indepent for sure. 
> 
> Best regards
> Ditrk
> 
> 
> Am Montag, 17. Oktober 2005 09:01 schrieb Hiroshi Watabe:
> > Dear Gate-users,
> >
> > I try to do 4 simulations with different seeds. In the past gate-users
> > talk, I found the article (posted by Mutanga Theodore on 17 Dec 2004)
> > which explain how to generate different seeds files.
> > As the article explains, I did mock simulation with 10 Bq source and
> > generated four different endOfRun.rndm. By using the command
> > /random/resetEngineFrom, I initialized random seeds.
> > I supposed to get four different results but four simulations produced
> > very similar results. I say "similar" because I got exactly same
> > projection data but the root outputs were slightly different in each
> > others. In the root file, I found only event ID and time
> > were different but else (for instance, source position and global
> > position) were exactly same in Singles trees (I'm doing SPECT simulation).
> >
> > Any suggestions and advice are appreciate.
> >
> > Hiroshi
> >
> > --------------------------------------------------
> >              Hiroshi Watabe, PhD
> >
> > watabe at ri.ncvc.go.jp
> > Department of Investigative Radiology
> > Advanced Medical Engineering Center
> > National Cardiovascular Center Research Institute
> >
> > 5-7-1 Fujishirodai, Suita, Osaka 565-8565
> >
> > Tel:06-6833-5012-2560 or 06-6833-5004-2560
> > Fax:06-6835-5429
> > --------------------------------------------------
> >
> > _______________________________________________
> > gate-users mailing list
> > gate-users at lphe1pet1.epfl.ch
> > http://lphe1pet1.epfl.ch/mailman/listinfo/gate-users