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Multiple independent random number streams cannot be implemented.

• To: mathgroup at smc.vnet.net
• Subject: [mg130148] Multiple independent random number streams cannot be implemented.
• From: Roger Wilson <rogerhw999 at gmail.com>
• Date: Thu, 14 Mar 2013 07:14:50 -0400 (EDT)
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Hopefully the title is enough of a red flag for someone to try to prove me wrong.

I want to implement two functions; lets call them f and g so that they both return random numbers.  For example...

f[]:=RandomReal[];
g[]:=RandomReal[];

However I want f and g to return the same number when they're called for the nth time.  So the first call to f is always the same number and the first call to g is always the same number.

In the above case (on my machine)...
SeedRandom[1]; {f[], g[]} gives {0.168697, 0.113119}

and of course..
SeedRandom[1]; {g[], f[]} gives the same {0.817389, 0.11142}

Essentially I want f and g to to be independent random sources.

It is possible to localize the random number generators using BlockRandom but I do not see how that helps me in this case.  BlockRandom localizes the state of the random number generators within the block where as I want to localize them into the symbol names.

Roger

• Follow-Ups:
  • Re: Multiple independent random number streams cannot
    • From: Waclaw Kusnierczyk <waku@idi.ntnu.no>
  • Re: Multiple independent random number streams cannot be implemented.
    • From: Sseziwa Mukasa <mukasa@gmail.com>