Does anyone know of a patch/object that calculates the derivative of an incoming sequence of messages (not signal)? 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.
Thanks Oded
# What is DPCM, and how is derivative defined in it? Are the messages coming with constant time intervals? # I was thought that the simplest model of the derivative in discrete signals is calculated by taking the differences between successive samples and dividing the difference to the time interval between them. # Where do you keep the last 4 values? Maybe using a table is easier. -ugur-
On 9/3/07, Oded Ben-Tal oded@ccrma.stanford.edu wrote:
Does anyone know of a patch/object that calculates the derivative of an incoming sequence of messages (not signal)? 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.
Thanks Oded
-- ___________________________________________________ Oded Ben-Tal http://ccrma.stanford.edu/~oded oded@ccrma.stanford.edu
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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__
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Frank Barknecht -
Oded Ben-Tal -
ugur guney