This is cool, but it has some serious numerical issues that ought to be ironed out. I took their example cubic function, and plotted the first, second and thir

This is cool, but it has some serious numerical issues that ought to be ironed out. I took their example cubic function, and plotted the first, second and third derivatives. The third derivative goes crazy as x goes away from zero. (See screenshot http://farm6.static.flickr.com/5088/5361267299_a976c64dcb.jpg http://farm6.static.flickr.com/5088/5361267299_a976c64dcb.jp...)