package com.imsl.test.example.math;

import com.imsl.math.*;

/**
 * <p>
 * Solves a system of nonlinear equations. </p>
 *
 * This example solves the following system of nonlinear equations: 
 * $$
 * \begin{align}
 * y_0 &= x_0 + \exp(x_0-1.0) + (x_1+x_2)^2-27.0 \\
 * y_1 &= \exp(x_1-2.0)/x_0 + x_2^2 - 10.0 \\
 * y_2 &= x_2 + \sin(x_1-2.0) + x_1^2 - 7.0
 * \end{align}
 * $$
 *
 * @see <a href="ZeroSystemEx1.java">Code</a>
 * @see <a href ="doc-files/ZeroSystemEx1.out">Output</a>
 */
public class ZeroSystemEx1 {

    public static void main(String args[]) throws com.imsl.IMSLException {

        ZeroSystem.Function fcn = new ZeroSystem.Function() {

            @Override
            public void f(double x[], double f[]) {
                f[0] = x[0] + Math.exp(x[0] - 1.0)
                        + (x[1] + x[2]) * (x[1] + x[2]) - 27.0;
                f[1] = Math.exp(x[1] - 2.0) / x[0] + x[2] * x[2] - 10.0;
                f[2] = x[2] + Math.sin(x[1] - 2.0) + x[1] * x[1] - 7.0;
            }
        };

        ZeroSystem zf = new ZeroSystem(3);
        double guess[] = {4, 4, 4};
        zf.setGuess(guess);
        new PrintMatrix("zeros").print(zf.solve(fcn));
    }
}