Re: rand("state")

[Francesco Potorti`]

>I was worried about the likelihood that random streams generated on the
>nodes of a cluster of computers might overlap.  My conclusion was that
>the probability is so small it can be ignored, even on a large cluster.

If the simple results I got is correct, for computer that exists today
or in the next many years, the probability is negligible from any
possible point of view.

Suppose you have a grid of extremely powerful computers ten years from
now, and you need to generate 1e50 independent sequences of random
numbers, each 1e50 numbers long.  If you choose the seeds randomly, the
probability of any two overlapping is around 1e-5851.

I am no expert in physics, but I suspect this is similar to the
probability of a ball appearing on my desk because of quantic
fluctuations.

If the formula I posted previously is correct.

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Francesco Potortì (ricercatore)        Voice: +39 050 315 3058 (op.2111)
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