[PD] Understanding the mechanics of rebuilding Pd's DSP graph

Jonathan Wilkes jancsika at yahoo.com
Mon Nov 23 20:44:14 CET 2015


Hi William,In practice, I'm not sure how inefficient they are.  Pd already has [switch~] for situations where some 
subpatch doesn't need to compute audio.
-Jonathan
   

 On Monday, November 23, 2015 1:58 PM, William Huston <williamahuston at gmail.com> wrote:
 

 > what qualifies as a "complex orphaned network"?

and [osc~] with no wires is the most trivial example of an 
orphaned tilde object. There is no need to add  it to the
DSP graph or compute audio for such. 

An orphaned (tilde) network is created when I connect two orphaned 
tilde objects together.

> how do you determine whether a dsp-object has I/O?

A tilde object is "active" (not orphaned) when its output is connected to 
any object which stores computed audio in memory, or sends audio 
external to PD,  like [dac~], [tabwrite~], or [writesf~].  

(OK-- externals become tricky, as PD's DSP compiler needs to understand
wither the external object sends audio outside PD, such as across
a network, or stores audio in memory)

A [throw~] / [catch~] network is orphaned if the output of [catch~]
is connected to an orphaned tilde network. 

These kinds of orphans (at least for PD vanilla objects) 
should be easy to detect if it is true as Jonathan says,
that there is a single DSP graph for each running instance of PD,
since they can be determined by examining the netlist alone. 
The reason I'm asking this is because since moving to a Raspberry Pi-based setup,
I'm trying to optimize my code for performance, since there is definitely a 
CPU budget on a Pi which is easily exceeded. 

I want to understand whether orphaned tilde objects are part of
the DSP graph, and steal cycles? or are they harmless? 



On Mon, Nov 23, 2015 at 1:18 PM, IOhannes m zmölnig <zmoelnig at iem.at> wrote:

On 11/23/2015 06:31 PM, William Huston wrote:
>
> *What about a complex "orphaned network" containing various tilde objects?*
>

what qualifies as a "complex orphaned network"?
how do you determine whether a dsp-object has I/O?


mfds
IOhannes


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