Example 2: Nonlinear least-squares problem

using System;
using Imsl.Math;

public class NonlinLeastSquaresEx2 : NonlinLeastSquares.IJacobian
{
	public void F(double[] x, double[] f)
	{
		f[0] = 10.0 * (x[1] - x[0] * x[0]);
		f[1] = 1.0 - x[0];
	}

	public void Jacobian(double[] x, double[,] fjac)
	{
		fjac[0,0] = - 20.0 * x[0];
		fjac[1,0] = 10.0;
		fjac[0,1] = - 1.0;
		fjac[1,1] = 0.0;
	}


	public static void  Main(String[] args)
	{
		int m = 2;
		int n = 2;
		double[] x = new double[n];
		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 NonlinLeastSquaresEx2());
		
		for (int k = 0; k < n; k++)
		{
			Console.Out.WriteLine("x[" + k + "] = " + x[k]);
		}
	}
}

Output

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