package com.imsl.test.example.math;

import com.imsl.math.*;

/**
 * <p>
 * Quadrature Example 2: Approximates the integral of \(e^{-x}\). </p>
 * The integral $$\int_0^\infty e^{-x} \, dx$$ is computed and compared to its
 * expected value.
 *
 *
 * @see <a href="QuadratureEx2.java">Code</a>
 * @see <a href="doc-files/QuadratureEx2.out">Output</a>
 */
public class QuadratureEx2 {

    public static void main(String args[]) {

        Quadrature.Function fcn = new Quadrature.Function() {
            @Override
            public double f(double x) {
                return Math.exp(-x);
            }
        };

        Quadrature q = new Quadrature();
        double result = q.eval(fcn, 0.0, Double.POSITIVE_INFINITY);

        double expect = 1.;
        System.out.println("result = " + result);
        System.out.println("expect = " + expect);
    }
}