[PD] derivative?

[Frank Barknecht]

Hallo,
Oded Ben-Tal hat gesagt: // Oded Ben-Tal wrote:

> Does anyone know of a patch/object that calculates the derivative of an 
> incoming sequence of messages (not signal)?

A very simple way is a cross-connected trigger with substraction: 

 [t f f]
   \/
   /\
  [- ]

to take the difference between successive values as derivatives.

> I am trying to figure out a way of calculating the derivative (by DPCM) 
> but all I can come up with are very cumbersome and ugly (keeping the last 
> 4 values and then switching their positions ready for the next iteration 
> works in c, but seems awkward in pd) I presume there is a simple elegant 
> way of doing it but I just can't see it.

Maybe some objects of the [list]-abs collection can make what you want
easier to patch, especially [list-lastx], [list-map] and
[list-reduce]. I would try to help more if you could explain the
algorithm you want to use with a bit more depth.

Ciao
-- 
 Frank Barknecht                 _ ______footils.org_ __goto10.org__