Question: And can you give me an example of an algorithm?
[alt text http://ryancalderoni.com/archive/ideal\_curve.jpg](http://ryancalderoni.com/archive/ideal_curve.jpg)

EDIT: And then how would I calculate the math using Javascript? Can someone add that? Sorry to not include that context originally..

NOTE: I am using 'flot' to graph it and the input for flot is a javascript array like this:

[[x,y],[x,y],[x,y]...]

So given the values that change the curve I output all the points to an array with a loop and spit it out to flot to graph.

Answer: 
Try to lookup sigmoid function, it looks a lot like it.

[![alt text](https://i.stack.imgur.com/foU2Q.gif)](https://i.stack.imgur.com/foU2Q.gif)  

(source: [iag at ulcar.uml.edu](http://ulcar.uml.edu/~iag/CS/Sigmoid-function.GIF))
A [Bézier curve](http://en.wikipedia.org/wiki/B%C3%A9zier_curve)? The corresponding algorithm to draw it would be [de Casteljau's algorithm](http://en.wikipedia.org/wiki/De_Casteljau%27s_algorithm).