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Question random number generation 

Keywords: ranecu, random
Forum: Run Management
Date: 07 Nov, 2005
From: Carter Hall <Carter Hall>

Hello,

I'm trying to simulate a large number of events, something like several billion. I've been doing this by running multiple jobs in parallel, using the ranecu engine and setting a unique initial seed for each job with HepRandom::setTheSeed(seed).

But I've just realized that this doesn't work so well. One problem is that the ranecu engine uses a table of initial seeds of length 215, and HepRandom::setTheSeed(seed) just picks an entry in this table. So it's not possible to have more than 215 independent jobs running in parallel - I had been attempting to run 2000 jobs.

Another problem seems to be that random numbers are repeating even within the first 215 jobs.

Is there another engine I can use to get more independent random numbers? Are there any examples illustrating the use of other engines? Thanks,

Carter

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1 Feedback: Re: random number generation   (Gabriele Cosmo - 08 Nov, 2005)
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