Hi,

Can anyone explain to me how I add a logarithmic label to an array. Right now I'm using the internale message (; array1 xlabel 0 1 2 3 ...) to add labels to my array. But this only gives me a linear scale.
My scenario is as follows: I display a frequency spectrum with an array. The standard is of course a linear view if the bins. I already managed it to display my spectrum in a logarithmic scale. Now I also want to add a label to the x-axis with a logarithmic scale.

Thanks for your help.

Best,
Matthias

An array displays its indexes in the x-axis, I'm pretty sure you know that. How can the indexes of an array be logarithmic? Can you share what you've done so far?

Hi,
here is a patch demonstrating what I try to do:
abstract_spec2.pd
It writes the magnitudes of an audio input (the one inlet) in two arrays. One with a linear frequency scale on the x-axis and one with a log frequency scale. My goal is it to label the x-axis with the matching frequencies in Hz and not just the indices of the array (aka the bin numbers).
Thanks for your help.

best,
Matthias

@bilberry79 Hello Matthias..... I don't know of an easy automatic way to do that. You could derive all of the log (10?) values for 20, 40, 60 etc. and using $ values in your message to y-label replace the values that you have with the log values automatically, but they will still appear spaced linearly.
It is probably easier just to calculate them by hand and enter them in the y-label message....
David.

Or you might try using data structures. It's probably possible, although it surely won't be easy.

@whale-av thanks for the suggestion but you're right, the scale still will be linear.

@LiamG I never used data structures in PD before, though I read this manual real quick and it looks like it might be possible but it's a hell of a workaround

Would be great if we had logarithmic representations of arrays in PD.

I agree, I've always found data structures to be more trouble than they are worth.

You might try bringing this question up on the list, where the PD developers can respond.

I think about it. Thanks for your help.

You could use canvas labels created dynamically
an idea gleaned from Help Browser 13.sliderule.pd in 4.data.structures
log-label.pd

Oh right. Thanks that might really help. I'm going to adjust this patch a little and share the results.