# Random algorithm

Wed Nov 12 16:41:41 CST 2008

```Jacques Hausser wrote:

>>>> Me too.  Wouldn't it suffice to do this before each
>>>> run?:
>>>>   set the randomSeed to random(4570422)
...
>> It would seem that resetting the randomSeed each time you use the
>> random function would only have a 1-in-4,570,422 chance of getting
>> the same seed as the previous run, no?
>
> It depends of what you use to reset the randomSeed.

Right.  Using even a psuedo-random number would seem acceptable in most
cases because it's being used to reset the basis of the next
psuedo-random number.

By changing the basis each time it's run, it would seem that the
likelihood of emerging patterns would be greatly reduced.

Since Rev's randomSeed is in the range of 4 million+, it seems that it
would take an extraordinarily large sequence of operations to have any
discernible pattern.

> Some papers (reference burried to deep in my memory to be retrieved)
> suggest to generate an array of random numbers at start, and then to
> reset the seed each time it's needed with one of these elements, the
> index being randomly choosen. And the first x random numbers you draw
> are used to replace the array for the next time...
> But that is only a sophisticated kind of reshuffling.
> I just looked at the Web of Science for "Random number generator":
> 1252 papers. I do not think there is ONE obvious solution...

For pure science, probably not.  But for getting work done in Rev, maybe.

True, the method I mentioned above is still not truly "random", but some
philosophers among us might argue that in the meta-patterns that drive
the universe there is ultimately no such thing as pure "randomness".
Even roulette wheels have a discernible bias; more than a few people
have made good money from observing them carefully (which is why casinos
today often swap wheels among tables periodically).

So all that said, I'm having a tough time imagining the sorts of
applications for which a one-in-four-million chance of having a pattern
which even then might be discernible only after hundreds of thousands of
iterations would be built in Rev.

Maybe I just missed something from an earlier post.

What is the application in question?

People build the most amazing stuff with this tool....

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