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?
thanks, dan On Mar 19, 2010, at 4:15 PM, Chris Wood wrote: > See also gaussian curve/bell curve/s-curve... Although of course that was a > straight spline curve in the first pic. Splines will give you what you want, > but maybe not in the most simple way. > > Chris > > > On 19 Mar 2010, at 19:52, Dan Winckler wrote: > >> Thanks, Tom and Jon! I remembered Grapher earlier today and it was a big >> help, even though polynomial curves are not among its examples (sure beats >> my old TI-82). Now to tweak the numbers until they give me the shape I >> need. Additional help still welcome if offered. :) >> >> best, >> dan >> >> >> >> <Screen shot 2010-03-19 at 3.49.57 PM.png> >> >> >> On Mar 19, 2010, at 3:40 PM, Jon Pugh wrote: >> >>> At 3:14 PM -0400 3/19/10, Dan Winckler wrote: >>>> What do you call a curve like the one in the attached image? Rather, >>>> what's the mathematical term for the equation that produces such a double >>>> curve. I am trying to scale an incoming float number (0.0 1.0) so that >>>> it changes more quickly in the middle of the range (~0.2 - 0.8) than at >>>> the top and bottom (~ 0.0 - 0.2, 0.8 - 1.0). Right now I've got >>>> exponential scaling, which works for the bottom of the range but not the >>>> top. >>> >>> This is a curve produced by a polynomial equation. I recommend opening the >>> application Grapher, which came with your Mac, and entering this equation: >>> x = y^3+y^2+y >>> >>> This will give you a curve approximating the one you've drawn. Then you >>> can play with adding numbers before the various terms (i.e. 3y^3, etc) to >>> change the shape of the curve. >>> >>> Good luck. >>> >>> Jon >>> _______________________________________________ >>> 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/dan%40danwinckler.com >>> >>> This email sent to [email protected] >> >> _______________________________________________ >> 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/psonice%40gmail.com >> >> This email sent to [email protected] > _______________________________________________ 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]
