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Posted by Gert-Jan Strik on 06/15/07 16:14
> >> Well, that definitely rules out newid() as a "good" pseudo random number
> >> generator, then. A sequence of random numbers should have a chance to
> >> hold duplicates.
> >
> >Good observation. And so you correctly concluded that RAND() also does
> >not do this.
>
> Am I reading you incorrectly, or are you saying that the sequence of
> numbers generated by RAND() never produces the same value twice?
No, I am not saying that. It might, I haven't analyzed the algorithm
thoroughly. But that doesn't matter. A good pseudo random number
generator should incorporate the idea that in a range of 2 billion
values, there is a one in 2 billion chance that the same value is
selected next. And after that, then again there is a one in 2 billion
chance it will appear again. And that is something the algorithm doesn't
do. The algorithm is totally deterministic.
Gert-Jan
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