[PD-dev] avoiding reuse of vectors in multichannel external

/*j jasch at kat.ch
Mon Apr 3 11:43:09 CEST 2006


hello,

I'm working on porting the icst-ambisonics externals to PD and i have  
a couple of questions concerning the dsp-structure of externals in PD.

1)
I'm currently experiencing what i think is reuse of signal vectors in  
the dsp-chain. it looks like input-vectors get overwritten with the  
output-vector before I'm done with my multichannel processing. in MSP  
there's a flag to prevent this. it's part of the x->pxobject the x- 
 >x_obj.z_misc = Z_NO_INPLACE; flag. is there something equivalent in  
PD?
from the MSP docs: "If you set this bit in z_misc, the compiler will  
guarantee that all the signal vectors passed to your object will be  
unique. It is common that one or more of the output vectors your  
object will use in its perform method will be the same as one or more  
of its input vectors. Some objects are unable to handle this  
restriction; typically, this occurs when an object has pairs of  
inputs and outputs and writes an entire output on the basis of a  
single input before moving on to another input-output pair."

2)
what i could glean from the docs/pdf's there is no way a signal inlet  
could be used for message-input at the same time, is that correct or  
is there a hack to get this work? i specifically need the left-most  
inlet to set the objects state etc. what the standard way of dealing  
with this in PD?

I'm grateful for any hints or ideas

/*j






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