posted 12 April 2003 02:32            

How can I change a variable in a funtcion with another funtion from outside?

r := Random new.
t := 0.
x := 0.05.
a := 3.95.
p := #( 0 2 4 6 7 9 11 12).
200 timesRepeat: [
fr := a*x*(1-x).
self
keyDownAt: t s
duration: 15 s
frequency: 2 c sharp + (p at: ((fr*7 + 1) truncated)) .
t := t + (7 * r next).
x := fr].

Now I would like to change a every 20 repeats and change the octave through another function?
Thanks for help

Best Regards

posted 12 April 2003 12:33            

!KeyDown nextChaotic: !k seed: 0.77 reset: !Inject

In answer to your question on how to change the octave in your script, if you were to use a do: loop instead of timesRepeat: then you would have an index (i) that you could test for the number of repeats. Every 20 times you could change the octave number. You would need another variable to hold the octave (which could take the values -3, -2, -1, 0, 1, 2, 3 as the numbers of octaves above or below the octave of the pitch you read out of the array using fr). For example,

oct := 0.
1 to: 200 do: [:i
fr := a*x*(1-x).
((i mod: 20) = 0) ifTrue: [oct := (fr * 2 - 1 * 3) rounded].
self
keyDownAt: t s
duration: 15 s
frequency: 2 c sharp + (p at: ((fr*7 + 1) truncated)) + (oct * 12 nn).
t := t + (7 * r next).
x := fr].

I didn't actually run the compiler on this, so please just look at it as a suggestion as to how to approach it.

posted 12 April 2003 13:52            

quote:

---

Originally posted by SSC:
You may prefer to do this in real time, without having to construct a MIDI script. You can ask for the value of the next iteration of the map of the interval each time you trigger, using the expression:

!KeyDown nextChaotic: !k seed: 0.77 reset: !Inject

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Sorry but perhaps I expressed my question the wrong way. In the following function I want to change th variable "a" every 20 repeats. I can do it with another if-function but it would interest me how I can use the expression from above. Please excuse my difficulties with the english language.

| r t x fr a p oct|
r := Random new.
t := 0.
x := 0.05.
a := 3.89.
p := #( 0 2 4 6 8 9 11 12).
oct := 0.
1 to: 200 do: [:i |
fr := a*x*(1-x).
((i mod: 20) = 0) ifTrue: [oct := (fr * 2 + 1) rounded].

posted 12 April 2003 15:04            

The variable a in your script corresponds to the hot value (!k + 3) in the expression I suggested. This is the scalar value (usually called R) that determines whether your iterated function will go into a cycle or whether it will be in a chaotic area. You could change !k every 20th time by: