[Jack-Devel] graph simplification using mathematics?

[Thomas Brand]

On Sun, July 3, 2016 11:52, Fons Adriaensen wrote:
> On Sun, Jul 03, 2016 at 05:04:17AM +0200, Thomas Brand wrote:
>
>
>> Given that a processing graph doesn't change constantly (except in some
>>  special cases), i'd imagine to kind of "freeze" the plugins setup to a
>>  single instance to gain more room per cycle. Maybe this is just a pipe
>>  dream. Having all involved DSP in a declarative text language instead
>> of BLOBs. Whole DAWs could be built like this. As i said, just a pipe
>> dream
>
> Keep in that in all but the simplest algorithms, audio processing doesn't
>  just involve calculations on samples, but also logic, maintaining state,
>  and in general things that don't happen at the audio sample rate but
> have their own independent timing which isn't regular and can't be
> predicted. Faust isn't particularly good at any of that.
>
>
> In theory all of that could be expressed in a 'formula', but the
> complexity of such a formula will explode exponentially unless you express
> it as a chain or graph of separete operations with no or limited
> interaction. And then we are back where we started.
>

it's a very theoretical thing indeed, with the premise that as long as a
plugin acts deterministically, it could be expressed as a formula (which
can get large/complex). That alone doesn't make it "better" or solve any
problem yet, easy to agree.

> You may think that running the entire combined algorithm sample per
> sample, avoiding all intermediate buffers, would be more efficient than
> having separate modules which communicate by passing blocks of samples
> between them. But that is NOT the case. Short loops using a small set of
> variables make much better use of CPU registers and the cache, and will be
> faster.
>
> In other words, even if it would practically possible to do what you
> suggest, nothing will be gained, on the contrary.
>

OK. Thanks for your insights Fons! As always much appreciated.

> Ciao,
>
>
> --
> FA
>
>
> A world of exhaustive, reliable metadata would be an utopia.
> It's also a pipe-dream, founded on self-delusion, nerd hubris
> and hysterically inflated market opportunities. (Cory Doctorow)
>
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