Interesting Challenge...

[Bartek]

Hi,

So I think this formula, or a variant thereof, will be perfect. I can see why various values were selected but what is the logic behind the value 2836 - out of curiousity, why not something higher or lower?

This generator is based on so-called linear congurency - the most popular method to generate random numbers. I found it in one book about casino gambling (Casino Operations Management by J.Kilby, J. Fox) and then implemented in VBA, so I don't know the exact origin of the generator.
The core principle of random number generator is the Mod operation with high prime number - in that way random generators are similar to encryption tools.

 

[Andrew Fergus]

Thanks very much! I tried your formula last night in a simulator and I couldn't detect a single repeating value in the first 685 million numbers. However, if I try to use other values (in place of the two factors for 2^31, including a high prime number) then I start getting repeats very early into the run.....I'm not sure why, or what is so significant about using 127773 that it yields such a high non-repeating sequence compared to other prime numbers.

Thanks again
Andrew