> Chris Wright also threw in the sigmoid function > (http://en.wikipedia.org/wiki/Sigmoid_function) -- thank you, Chris(x2). The > difficulty is in fitting the curve to the desired range -- any tips, > mathemagicians?
Going with the sigmoid, you have an equation like this: y = 1 / (1 + e^-x) We can generalize this a bit more, and turn it into this: y = r / (1 + e^(-(x - o) * s)) Where r is the "range" (0 to r), s is the "scale" (or "sharpness"?) (higher numbers make the change from 0 to r occur more rapidly, default is 1), and o is the "offset", where the transition takes place (normally 0). Varying r, s, and o will give you a sigmoid mapped however you'd like. (and varying e will make you impossibly powerful ;) The other equations (sin being another good easy one) have similar scale/offset changes to tweak them as necessary. (disclaimer: i'm not a real mathemagician, and was also educated by the US education system ;) Chris _______________________________________________ Do not post admin requests to the list. They will be ignored. Quartzcomposer-dev mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/quartzcomposer-dev/archive%40mail-archive.com This email sent to [email protected]
