[PD] [random] and seed value

[Julian Brooks]

Thx for fix & additional info IOhannes - not too shabby then...



------- Original Message -------
On Thursday, December 15th, 2022 at 11:23, IOhannes m zmoelnig <zmoelnig at iem.at> wrote:


> 
> 
> On 12/14/22 23:55, Julian Brooks wrote:
> 
> > Yes, I'm one of those...
> 
> 
> then i think you should start setting an explicit seed right now.
> 
> the simplest way i've found to force the currently hardcoded seed (for
> the first instantiated random generater), is something like this:
> 
> 1. seed the random generator with 255406
> 2. discard the first 3186 random numbers
> 
> like so:
> #N canvas 2082 640 533 344 12;
> #X msg 307 69 seed 255406;
> #X msg 327 123 3186;
> #X obj 327 148 until;
> #X obj 230 246 spigot;
> #X msg 307 174 1;
> #X obj 230 271 print;
> #X msg 202 166 bang;
> #X obj 307 94 t b b a b;
> #X msg 367 172 0;
> #X obj 230 221 random 100;
> #X obj 281 197 t a;
> #X obj 367 200 t f;
> #X text 311 45 reset;
> #X connect 0 0 7 0;
> #X connect 1 0 2 0;
> #X connect 2 0 10 0;
> #X connect 3 0 5 0;
> #X connect 4 0 11 0;
> #X connect 6 0 9 0;
> #X connect 7 0 4 0;
> #X connect 7 1 1 0;
> #X connect 7 2 10 0;
> #X connect 7 3 8 0;
> #X connect 8 0 11 0;
> #X connect 9 0 3 0;
> #X connect 10 0 9 0;
> #X connect 11 0 3 1;
> 
> > [random] seems to rear its head now & then.
> 
> 
> of course it loops. it's a pseudo random generator.
> however, i find that the underlying algorithm is somewhat perfect with
> regard to repetition (last time i checked, it required about 4294967295
> iterations to repeat, which is pretty good for a 32bit integer number).
> 
> that's not to say that the distribution for small ranges as output by
> [random] might not be ideal.
> 
> > My memory is that when asked on here, Miller was a little coy about the algo (when was highlighted on-list as an 'interesting' [non-standard] implementation:)
> 
> 
> iirc, miller always claimed that he was just blindly hitting the number
> keys to generate large numbers.
> 
> i don't fully trust this statement for the actual random generator
> (given that it consumes all possible numbers before repeating), but for
> the seed generator this is somewhat plausible, as this one only takes
> 536870912 iterations to repeat itself (so the PRNG itself has an 8-times
> longer period)
> _______________________________________________
> Pd-list at lists.iem.at mailing list
> UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list