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Forum: Multithreading
Re: None Unique Events
Re: Note Re: Unique Events (Andrea Dotti)
Date: 08 Aug, 2016
From: <herr_apa>

Hi Andrea,

I delved into the code a little bit. As you say, it looks like two seeds are prepared per event by default. Initially they are doubles, but then they are cast to long by the G4RNGHelper class. This is done by multiplying by 100000000, so the seed queue contains numbers between 0 and 10^8 - 1. Every event, two seeds are popped from the queue and used to initialize the RNG. I checked for my RNG class (MTwistEngine), and information from both seeds is indeed used.

The number of possible ways to initialize the RNG is thus 10^16. As long as the number of events doesn't get close to that, the probability of getting identical events is low.

// Anders

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