mexican hat

Roman Thilenius's icon

does anyone have a function generator (float data) to generate a "mexican hat" waveform?

i have a custom gaussian generator, and i have peter castines patch for
laplace, (which i think is identically with the mexican hat) but both dont
create curves for waves, they are only creating random numbers of the
respective distribution.

-110

lut lei's icon

Not sure what kind of function you are after, but there are some very handy patches out there for similar things.

Try the patch sm.window-maker by Steven Miller.

Also one of Fredrik Olafsons abstractions could be the one. Look at "Make envelopes".

And Graham Wakefield posted a very nice patch in this thread:

Maybe not what you where after?

Roman Thilenius's icon

sm.window-maker ... yeah i have my custom window makers, too, that is what it is about.

the function "flat-top" seems to be at least something similar to laplace, the form
looks familiar, just the weighting seems different.
mexican hat / laplace should result in almost identical sqare-roots (energy) for both poles.

X37V's icon

OK, let me start off by saying that I know fuck all about this.

However, if a mexican hat is a negative normalised distribution of a second derivative of a Gaussian function, then is this any help?

Gaussian function.

a*e^(-((x-b)^2)/(2*(c^2)))

Second derivative of a Gaussian function.

(a*e^(-((b-x)^2)/(2*c^2)) * (b^2 - 2*b*x - c^2 + x^2)) / c^4

;)

Roman Thilenius's icon

... hmm ... set new members to "moderated" ?

EMV's icon

Or add a difficult captcha for new members? Or implement the Akismet API? (the latter is probably a lot of work, but it works very well)