// test_gauleg.java

public class test_gauleg
{
  public test_gauleg()
  {
    double area;
    double a = 1.0;
    double b = 2.0;
    int n = 4;
    double x[] = new double[n+1];
    double w[] = new double[n+1];

    System.out.println("test gauleg.java integrate f(p)=p^2 from a=1 to b=2");
    System.out.println("calling new gaulegf(a, b, x, w, 4)");
    new gaulegf(a, b, x, w, n);
    System.out.println("x="+x[1]+" "+x[2]+" "+x[3]+" "+x[4]);
    System.out.println("w="+w[1]+" "+w[2]+" "+w[3]+" "+w[4]);
    area = 0.0;
    for(int i=1; i<=n; i++)
    {
      area += w[i]*f(x[i]);
    }
    System.out.println("exact area=7/3");
    System.out.println("computed area = "+area);
    System.out.println("error= "+(area-7.0/3.0));
  }

  double f(double p) // function to integrate
  {
    return p*p;
  }

  public static void main (String[] args)
  {
    new test_gauleg();
  }
} // end test_gauleg.java