seabed

There are many ways in MaxMsp to keep a running average of a signal. However, I would like to calculate instantly the mean and the variance of a whole signal. So by the time I load a sample in a buffer to have its mean and variance.

Is that possible somehow? This can be done easily in non real-time process programs like Matlab, but I want to do the calculations with MaxMsp.

calculating-mean-instantly

What do you mean by " a whole signal"? Are you talking about a loaded sample?

You can get all signal values of the sample/buffer with [uzi] and [peek].

@broc yeah, but it isn't instant as such.

for peak, divide the putput of +=~ through the output of index~.

for average, divie the output of average~ into +=~ through the output of the average window.

Weetterberg, yes I mean a loaded sample and by instantly I mean as fast as possible. I made a patch using uzi and peek, it takes a couple of seconds to do the calculations. Is there a faster way?

Actually Roman I didn't understand clearly what do you suggest.

Actually Roman I didn't understand clearly what do you suggest.
Cheers


The calculation involves Addition, Subtraction and Multiplication of each signal value.

So it may take some time depending on the buffer size.

But the Java external 'mxj buf.Op' will probably be faster.

(although personally I try to avoid Java due to possible issues with Mac OS X)

The calculation involves Addition, Subtraction and Multiplication of each signal value.
So it may take some time depending on the buffer size.

But the Java external 'mxj buf.Op' will probably be faster.
(although personally I try to avoid Java due to possible issues with Mac OS X)


Well as you said Broc I am having a few issues with Java and Max. Anyways, I am using uzi and peek to do my job.

So here is another question. After I calculate the mean I calculate how many samples exceed that value during 4 secs. Then I do the same for the next 4 secs of my sample. I want to scale that numbers in a range of 30 - 2000. The problem is that I don't know the range of that values before scaling. Any ideas or tricks that can help?

This would give you "instant" min, max, and mean values. There is definitely something to be said for using jitter matrices in such cases.

This would give you "instant" min, max, and mean values.  There is definitely something to be said for using jitter matrices in such cases.


Nice I will look it up. But now the problem is that I don't know in advance how many values exceed the mean per one second or four seconds. Any ideas about that?

jit.op @op >p would be a good place to start

jit.op @op >p    would be a good place to start


Calculating mean instantly