Function generation by input $y$ and $x$ values I wonder if there are such tools, that can output function formulas that match input conditions. Lets say I will make input like that:

$y=0, x=0$
$y=1, x=1$
$y=2, x=4$

and tool should generate for me function formula y=x^2. I am aware its is not possible to find out exact function, but it would be great to get some possibilities. I'm game developer and i need to code some behaviours in game mechanics, that aren't simply linear, sometimes I need for example arcus tangens, when i want my value to increase slower and slower for higher arguments. Problem is that I finished my school long time ago and simply I don't remember how does many functions looks like and such tool would be great to quickly find out what i need.

One of my favorite curve-fitting resources is zunzun.  They have many, many possible types of curves that can fit the data you give it.
