Question

BigDecimal has some modules which are hardly documented, like Newton.

“Solves the nonlinear algebraic equation system f = 0 by Newton’s
method. This program is not dependent on BigDecimal.

To call:

n = nlsolve(f,x) where n is the number of iterations required,
x is the initial value vector
f is an Object which is used to compute the values of the equations to be solved. “

And that’s it. Google did not result in something I could understand. I’d like to see some sample code with a bit of not-too-math-heavy explanation; to get a better idea of what that weird thing at the bottom of the toolbox is.

Answer 1

Newton’s Method is a way of approximating the root of an equation. It’s pretty good, provided your function meets some continuity requirements.

The method is:

1. Take a starting point
2. At that point, find a tangent line
3. Figure out where that tangent line has a root. Take the root as a point.
4. If you’ve reached tolerance, return this point as the solution. If not, go back to #1 using this as your new point.