Hi there and hi Victor,

I'm afraid to have no other choice to continue this thread today about a problem yet simple. 

I just want in order to set a given number of chnset(pfield value, string for name of the channel) and after set all corresponding chnget in a udo whose the xout ouptut is a array of k values.

I guess this is an other story of i- and k- rate confusion and maybe a misunderstanding of chnset and chnget behavior such as chnseti(ival[], []Sname), kval[] chngetk Sname[], etc.

I test the following code both in a udp maxmsp context and in a python script/app using udp, the problem comes from chnget who are set on the same S_name... I can just control the last channel, in this case ctrlArr[4] corresponding to the amplitude of an oscil. 

Here the code, out of udp context for test, with some comments which will be more telling than my words:



-odac ;--port=7777 



sr = 48000
ksmps = 32
nchnls = 2 
0dbfs  = 1

opcode test(n:i):(k[])

npfield:i = n // number of pfields

ctrlArr:k[] = init(npfield)
;S_chnstr:S = init(1)
bar:i[] = [1 ... npfield]

for j in [0 ... npfield-1] do
  chnstr:S = sprintf("%.02f_p%d", p1, bar[j])
  ;S_chnstr[j] = sprintf("%.02f_p%d", p1, bar[j])
  fieldvalue:i = pindex(bar[j])
  bar[j] = fieldvalue
  chnset(bar[j],chnstr)
  ;chnset(bar[j],S_chnstr[j])
  // use chnsetk, chnseti ?

  ctrlArr[j] = init(bar[j]) 
  ctrlArr[j] = chnget(chnstr) 
  ;ctrlArr[j] = chnget(S_chnstr[j])
  //I guess here is the problem : 
  //all chnget are seted on the same Sname, in this case the last
  // use chngetk ? Get an error linked to the previous chnset use

  print(j)
  print(bar[j]) // values of pfield
  puts(chnstr,1) // names of channels
  printk2(ctrlArr[0]) // values stored at index in a krate array 
  printk2(ctrlArr[1]) // 
  printk2(ctrlArr[2]) // 
  printk2(ctrlArr[3]) // 
  printk2(ctrlArr[4]) // 
od

xout(ctrlArr)
endop

instr 1
ctrlArr:k[] = test(5) 
asig = oscil(ctrlArr[4], ctrlArr[3])
outs(asig,asig)
endin 



i 1 0 1 80 0.5
e 

 

Thank you for your quick look, help and advice,

Best,

JB

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I think the problem is that the channel names are created at i-time and the loop runs at perf time.

Why don't you try first creating the array with the channel names - then using that in the k-rate loop. Don't put the sprintf() in the k-rate loop.


Prof. Victor Lazzarini
Maynooth University
Ireland

> On 9 Jun 2026, at 10:53, Jean Basile Sosa  wrote:
>
> Hi there and hi Victor,
>
> I'm afraid to have no other choice to continue this thread today about a problem yet simple.
>
> I just want in order to set a given number of chnset(pfield value, string for name of the channel) and after set all corresponding chnget in a udo whose the xout ouptut is a array of k values.
>
> I guess this is an other story of i- and k- rate confusion and maybe a misunderstanding of chnset and chnget behavior such as chnseti(ival[], []Sname), kval[] chngetk Sname[], etc.
>
> I test the following code both in a udp maxmsp context and in a python script/app using udp, the problem comes from chnget who are set on the same S_name... I can just control the last channel, in this case ctrlArr[4] corresponding to the amplitude of an oscil.
>
> Here the code, out of udp context for test, with some comments which will be more telling than my words:
>
> 
> 
> -odac ;--port=7777
> 
> 
>
> sr = 48000
> ksmps = 32
> nchnls = 2
> 0dbfs  = 1
>
> opcode test(n:i):(k[])
>
> npfield:i = n // number of pfields
>
> ctrlArr:k[] = init(npfield)
> ;S_chnstr:S = init(1)
> bar:i[] = [1 ... npfield]
>
> for j in [0 ... npfield-1] do
>  chnstr:S = sprintf("%.02f_p%d", p1, bar[j])
>  ;S_chnstr[j] = sprintf("%.02f_p%d", p1, bar[j])
>  fieldvalue:i = pindex(bar[j])
>  bar[j] = fieldvalue
>  chnset(bar[j],chnstr)
>  ;chnset(bar[j],S_chnstr[j])
>  // use chnsetk, chnseti ?
>
>  ctrlArr[j] = init(bar[j])
>  ctrlArr[j] = chnget(chnstr)
>  ;ctrlArr[j] = chnget(S_chnstr[j])
>  //I guess here is the problem :
>  //all chnget are seted on the same Sname, in this case the last
>  // use chngetk ? Get an error linked to the previous chnset use
>
>  print(j)
>  print(bar[j]) // values of pfield
>  puts(chnstr,1) // names of channels
>  printk2(ctrlArr[0]) // values stored at index in a krate array
>  printk2(ctrlArr[1]) //
>  printk2(ctrlArr[2]) //
>  printk2(ctrlArr[3]) //
>  printk2(ctrlArr[4]) //
> od
>
> xout(ctrlArr)
> endop
>
> instr 1
> ctrlArr:k[] = test(5)
> asig = oscil(ctrlArr[4], ctrlArr[3])
> outs(asig,asig)
> endin
>
> 
> 
> i 1 0 1 80 0.5
> e
> 
> 
>
> Thank you for your quick look, help and advice,
>
> Best,
>
> JB
>
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