Hey, I'm just starting out in Pd and I'm confused on how I would replicate a mathematical function. What I'm trying to do is generate a harmonic tree which is defined by the function...

x = value
d = destination harmonic
r = relative harmonic

f(xn+1) = f(xn) * d / r

The description of the site is here http://www.csounds.com/ezine/trees/

So what I have kind of does that but my question is, Can i create a patch that will do this can call itself again? (The f(xn) within the f(xn+1) part kind of confuses me)

Here is what I have so far..

Thanks.

The f(xn) and f(xn+1) part is just saying to use the output of the previous iteration and feed it into the current iteration. To me, it makes more sense to look at it like this:

f(xn) = f(xn-1) * d / r

f(xn-1) is the frequency output of the previous pass, and will give you f(xn). f(xn) then becomes f(xn-1) in the next pass.

An easy way to do this would be to make a subpatch with the equation and feed the output back into it. I made an example to illustrate this. In mine, I actually made two copies of the same patch; the output of 1 feeds into 2 and vice versa. Doing it this way allows you to have different destinations and relatives for each one, and you can chain as many as you like. I also set up a randomization option with min and max boundaries for the destination and relative.

Edit: by the way, thanks for bring this to concept to our attention. It's quite a musical approach to random intervals.

http://www.pdpatchrepo.info/hurleur/harmonic.tree.mmb.pd