On 7 Feb 2001 21:49:22 -0500, Pete wrote:
>Ron Parker wrote:
>
> <snippage>
>>find a better PRNG for 3.5, since we've all seen some of the bad results
>>you can get from the current one.
>
>        I am curious: "bad results?"  Is the povray generator *that*
>bad?  I mean, I have not done a rigorous statistical analysis of the
>random output but it seems as good (as bad?) as any other random
>number generator that I've used.  Whenever I get bad results, I use
>a different seed.

There's a high correlation between results, and it can lead to very
recognizable patterns.  I can find a reference to the original 
discussion here, if you're interested.

>        On thing I *have* noticed about the the random numbers that
>pov kicks out is that they *seem* to be more like a stream of pink
>"1/f" noise rather than the expected "white" noise: consecutive
>values do not differ as much as one would expect (it's as if a "real"
>random stream had been run through a mild low pass filter).  I have
>read that for more "artistic" uses, this "1/f" noise yeilds more
>"pleasing" or "natural" results.

Nope, the generator is the one I posted.  Nothing fractal about it.  It's
just not a very good generator.  The numbers (or at least the 12345) look
just a little arbitrary.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

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