The program I'm writing uses some differential equations and currently has the following: Euler's method. A busted 4th order Runge-Kutta method. Since I can't seem to work out why the RK is broken, are there any freely available libraries I could use instead?
p.s. If I got some of the terms/usages wrong here it's because math isn't really my subject. I got someone else to do the math code.