Example 1: Nonlinear least-squares problem

A nonlinear least-squares problem is solved using a finite-difference Jacobian.
using System;
using Imsl.Math;

public class NonlinLeastSquaresEx1 : NonlinLeastSquares.IFunction
{
	public void F(double[] x, double[] f)
	{
		f[0] = 10.0 * (x[1] - x[0] * x[0]);
		f[1] = 1.0 - x[0];
	}


	public static void  Main(String[] args)
	{
		int m = 2;
		int n = 2;
		double[] x = new double[m];
		NonlinLeastSquares zs = new NonlinLeastSquares(m, n);
		zs.SetGuess(new double[]{- 1.2, 1.0});
		zs.SetXscale(new double[]{1.0, 1.0});
		zs.SetFscale(new double[]{1.0, 1.0});
		x = zs.Solve(new NonlinLeastSquaresEx1());
		
		for (int k = 0; k < n; k++)
		{
			Console.Out.WriteLine("x[" + k + "] = " + x[k]);
		}
	}
}

Output

x[0] = 1
x[1] = 1

Link to C# source.