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Question Random generator correlation on quad-core PC 

Keywords: random number correlation quad-core PC
Forum: Run Management
Date: 08 Jun, 2007
From: Ilya <Ilya>

Dear all,

I have encountered a problem for which I don't see immediate solution. I am running 4 instances of one simulation program on a quad-core PC. These simulations use each different random seed numbers that are restored from different files in the beginning of run (similar as in /examples/novice/N03). I am using the defaul random generator.

Normally if I run the simulations on different PC's I get perfectly uncorrelated outputs. But after looking at the results obtained in 4 simulations on quad-core PC I found that the outputs are almost identical (only few events out of 3e6 are different).

I start the simulations within about 1 min time interval.

Can somebody explain why this happens (I guess it is due to some correlation of random generators but why...?)? And how to avoid this correlation?

I am using GEANT4.8.2.p1 under SUSE Linux

Thanks a lot for help, Ilya.

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1 None: Re: Random generator correlation on quad-core PC   (Vladimir IVANTCHENKO - 08 Jun, 2007)
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