[chuck-users] random seed

Stefan Blixt stefan.blixt at gmail.com
Sat Sep 11 16:37:14 EDT 2010


Sorry if I'm just acting like my head is made of wood, but 1: why would
anyone want to reproduce a chuck program sample-accurately? and 2: if
reproducing something sample-accurately is important to you, you can still
accomplish that by having a single global randomizer in your program
(seeded), and use that one.

/Stefan

2010/9/11 Kassen <signal.automatique at gmail.com>

>
>
> 2010/9/11 Stefan Blixt <stefan.blixt at gmail.com>
>
> Gotcha! Or at least, I can see a flaw here in ChucK's randomizers: there is
>> only one of them!
>
>
> That's not really a flaw; everything random, including the Std.rand*
> functions, all UGen noise sources and all noisy components of STK
> instruments depend on the same PRNG. I looked at the source back when I was
> obsessed with audio-rate resetting of the seed. This means that pieces with
> a set seed will be perfectly and sample-accurately be reproducible. CSound
> has always taken that into account, as well as backwards compatibility,
> which means that we can now listen to CSound pieces composed decades ago
> using modern converters for exact accuracy.
>
> This is a non-trivial feature from a "serious computer music" point of
> view.
>
> What we can do is implement our own PRNG in ChucK. Random number generators
> have been under a LOT of analysis as cryptographic security and thus banking
> and government secrets depend on them. To facilitate this PRNG of a strength
> way beyond our needs are open and free.
>
> For a more music-based look at it all I can't recommend "A Look at random
> Numbers, Noise and Chaos with Csound" by John Ffitch in the CSound handbook
> highly enough. Sadly I can't quickly find a online version; you may be more
> lucky or a local library might (should!) have the book.
>
> Yours,
> Kas.
>
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>
>


-- 
Release me, insect, or I will destroy the Cosmos!
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