[PD] reading and handling of multichannel data request

Mathieu Bouchard matju at artengine.ca
Fri Apr 14 18:54:06 CEST 2006


On Fri, 14 Apr 2006, Frank Barknecht wrote:

> As Derek recommended, you should definitely look a the matrix objects
> for this. To see this approach in action: I used [mtx_*~] to build the
> operator matrix of the PDX7 V2 (http://footils.org/cms/show/51). It just
> has 6 oscillator operators, however as they all can modulate each other,
> even with that I have 36 multiplications going on inside [mtx_*~], which
> would be horrible to patch without the matrix object. (I can show you
> some details if you're at ZKM during LAC2006.)

Note that execution time of such a thing goes with the number of inputs
times the number of outputs, so if there's some kind of organisation in
the way inputs contribute to outputs, then you should cut the work into
smaller parts, because if one of the smaller matrices is all zeroes, you
can omit it completely and that's less CPU usage.

Note also that one of the two matrix multiplicators for signals is
backwards (OTOH, from the perspective of its author, all other matrix
multiplicators for pd are backwards...). This just means that one kind of
object makes rows of the grid correspond to inputs, while the other makes
columns of the grid correspond to inputs.

 _ _ __ ___ _____ ________ _____________ _____________________ ...
| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada




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