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Question Not random enough 

Forum: Run Management
Date: 03 Jul, 2008
From: Yuri Burmistenko <Yuri Burmistenko>

My problem is that I get right result after too many histories. For example ti get flux tally of an isotropic source with no mateials and 40 cm between source and detector I need to make 3*10^7 histories. Too much, isn't it? In MCNP i get such a tally after 10^4 histories, or even less! I suppose somethig is wrong with my random numbers generator, but i set the seed. I wrote such a code:

void RunAction::BeginOfRunAction(const G4Run* aRun)
{
    long seeds[2];
    time_t systime = time(NULL);
    seeds[0] = (long) systime;
    seeds[1] = (long) (systime*G4UniformRand());
    // G4cout << "seed1: " << seeds[0] << "; seed2: " << seeds[1] << G4endl;
    CLHEP::HepRandom::setTheSeeds(seeds);
    CLHEP::HepRandom::showEngineStatus();
}  

and also i tryed with code:

 CLHEP::HepRandom::setTheSeed(time(0));

It doesn't help. It seems to me that I get the same random numbers all the time. Can any one help me, please?

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1 Feedback: Re: Not random enough   (Gumplinger Peter - 03 Jul, 2008)
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