Re: [stella] entropy & randomness

Subject: Re: [stella] entropy & randomness
From: "Thomas Jentzsch" <tjentzsch@xxxxxx>
Date: Wed, 10 Oct 2001 10:52:06 +0200
I wrote:
> I've done the same tests with the River Raid LFSR, here are the results:
> (The complete two bytes squence repeats after 57337 values.)


> While Chi square is still very bad, the Monte Carlo and Serial correlation test look much better. 
> I think, a high serial correlation should be avoided in games, because that's something the human player will notice. So that's maybe the most important test for us.

Oops again, I didn't notice that I had generated the test sequences by iterating the random function 16 times. With only one iteration, the River Raid results are quite similar to Suicide Mission. 

Now I've tested the random functions with different iteration values, and the tests show, that the serial correlation is divided by two with each iteration. (Monto Carlo mostly improves a bit too, but there's no exact rule, sometimes it's getting worse with one more iteration. All other values stay the same.)

So for better randomness, one should consider to call the random function more than once.

Have fun!
Thomas Jentzsch         | *** Every bit is sacred ! ***
tjentzsch at web dot de |

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