[PD] timing question

[Andy Farnell]

I don't know if you fell into the same trap as me Derek (because it confused
the heck out of me for ages), but if you've come from Csound, which is a true
multi-rate system it's easy to see messages the wrong way. On one hand
theres a useful analogy between Csound k-rate signals and the Pd message
domain, on the other hand their rates are actually the other way around
because Pd signal domain is much like Csound a-rate, but message domain
is "fast as you like (timeless) logical time". That's why I've gradually
trained myself to drop the habit of saying "control rate", when I mean 
"message domain". 


On Mon, 17 Dec 2007 17:58:01 +0100
Derek Holzer <derek at umatic.nl> wrote:

> OK, now I've got it. This can be explained! It especially makes sense 
> with the old "infinite looping" counter patch:
> 
> [f]X[+ 1]
> 
> where [+ 1] gets sent to the hot rather than the cold inlet of [f]. It 
> wouldn't be such a problem if it only counted on signal blocks, but it 
> actually counts as fast as the CPU will let it.
> 
> Great, concept is clear, I can continue!
> 
> best,
> d.
> 
> IOhannes m zmoelnig wrote:
> > Derek Holzer wrote:
> >> So now that I've been told that actually DSP objects are "slower", it 
> >> shakes up my world view a bit, so I'm looking for new metaphors to get 
> >> it back together ;-)
> > 
> > 
> > all the "slower" vs "faster" is non-sense.
> > 
> > signals are handled in a _synchronous_ way (they have to process 44100 
> > samples per second; synchronized with the soundcard); they do this 
> > continuosly (once you have started the audio-engine they will process 
> > 44100 samples/sec until the end of the world, or the audio engine gets 
> > stopped)
> > 
> > messages are handled in an _asynchronous_ way: "they happen on demand!"; 
> > they might occur every now and then; two messages might occur at the 
> > same logical time,...
> > 
> > so all in all, messages are way more powerful than signals.
> > 
> > unfortunately, CPU is not.
> > that is one reason, why the oh-so-powerful messages are not used for 
> > signal processing.
> > 
> > 
> > 
> > mfg.asdr
> > IOhannes
> > 
> 
> -- 
> derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
> ---Oblique Strategy # 22:
> "Be less critical more often"
> 
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