mexican hat

    Sep 10 2010 | 7:59 am
    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.

    • Sep 10 2010 | 8:38 am
      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?
    • Sep 11 2010 | 3:31 pm
      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.
    • Sep 17 2010 | 12:55 am
      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.
      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
    • Sep 21 2010 | 10:21 am
      ... hmm ... set new members to "moderated" ?
    • Sep 21 2010 | 11:08 am
      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)