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> Many thanks - I still remain relatively clueless, but that's my problem, not
> yours...
The pseudo random number generator of povray is
(as by peeking into the source) a linear congruence
generator. THE random number stream is a sequence
x(n), where
x(0) = 1
x(n+1) = (a*x(n)+b) mod 2^32
where a and b are fixed numbers. As each element of this stream is only
determined by its predecessor which is a 32-bit number, the stream must
repeat after at most 2^32 iterations. I tested that it does not repeat
earlier. So the stream is a repetition of a sequence of all 32-bit numbers.
More about pseudo random number generators can be read here:
http://crypto.mat.sbg.ac.at/results/karl/server/server.html
--
max_trace_level 256media{absorption.02}camera{location<1,.3,1.7>}sphere{0
.8pigment{color.6}interior{media{emission<2,2,-2>absorption 2}}hollow}#macro
p(f,n)plane{n f-1finish{reflection<f,1f>}}#end p(1y)p(1z-x)p(-1,-z)p(1x-y)
// Mark Weyer
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"Mark Weyer" <wey### [at] informatik uni-freiburgde> wrote:
>
> More about pseudo random number generators can be read here:
>
> http://crypto.mat.sbg.ac.at/results/karl/server/server.html
...or in Donald Knuth's "The Art of Conputer Programming", Vol. 2,
"Semi-numerical Algorithms" (that is IMHO the best source of information on
RNGs, including linear congruence generator used in POV-Ray).
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