I managed to solve it to the extent that it works well enough for me.
I pinched some code and changed it a little for my purposes:
https://stackoverflow.com/questions/32494230/newton-raphson-method-using-the-math-commons-library
public static void main(String args[])
{
//setup all variables
final double R =(new Double(args[0])).doubleValue(); //=250.0;
final double om1 =(new Double(args[1])).doubleValue(); //= 5.0;
final double om2 =(new Double(args[2])).doubleValue(); //= 15.0;
final double th21=(new Double(args[3])).doubleValue(); //= 29.07965;
final double th22=(new Double(args[4])).doubleValue(); //= 29.69008;
final double D_obs = th21 - th22;
BisectionSolver solver = new BisectionSolver();
UnivariateFunction f = new UnivariateFunction()
{
public double value(double s) {
return ((delta(R,om1,th21,s)-delta(R,om2,th22,s)) - (D_obs));
}
};
System.out.printf("The speciment offset is %.3f mm.\n", solver.solve(1000,
f, -3, 3));
}
On Thu, 4 Apr 2019 at 23:15, Matthew Rowles <rowle...@gmail.com> wrote:
> I'm having difficulty even beginning to solve this problem. All examples
> that I have found are either too simple or way too complex to digest.
>
> I want to to find the value S given a series of inputs. The function is
> univariate but non-linear. S will always be between -3 .. 3.
>
> I would like to use the Apache Commons library, as I have had prior
> experience in other sections of the code.
>
> For each time I want to solve my problem, I know the following information:
>
> double R =250.0;
> double om1 = 5.0;
> double om2 = 15.0;
> double th21 = 29.07965;
> double th22 = 29.69008;
> double D_obs = th21 - th22;
>
> The actual values will change between solutions, but they are fixed for
> any one particular solution.
>
> The value I want to find is:
>
> double S = 0.0;
>
> such that
>
> double d1 = delta(R,om1,th21,S);
> double d2 = delta(R,om2,th22,S);
> double D_calc = d1 - d2;
>
> have values to make
>
> double minme = Math.abs(D_obs - D_calc);
>
> a minimum. (ideally zero, but a minimum).
>
> The function delta is defined as
>
> public static double delta(double R, double om, double th2, double s)
> {
> if(Math.abs(s) <= 0.0001) //is the displacement == 0?
> {
> return 0.0;
> }
> else
> {
> return
> Math.toDegrees((-1*Cos(th2)*s-R*Sin(om)+Sqrt(-1*Math.pow(Cos(th2),2)*Math.pow(s,2)+2*Cos(th2)*Sin(om)*R*s-Math.pow(Cos(om),2)*Math.pow(R,2)+Math.pow(R,2)+2*Math.pow(s,2)))/(Sin(th2)*s));
> }
> }
>
> where, for example, Cosis defined elsewhere as
> Math.cos(Math.toRadians(val))
>
> Where/what can I read/do to get a start on this problem?
>
>
> Thanks
>
>
> Matthew
>
