// RKuser.java  test interface, user provides function and boundary
//              for ordinary differential equation.  y'=f(x,y)
//              starting at xmin,y using step size h, stop at xmax

public class RKuser implements RKlib
{
  public double xmin=1.0;
  public double xmax=2.0;
  public double y=1.0;
  public double h=0.1;
  public boolean printAll=true;

  public double f(double xx, double yy)
  {
    return xx*xx+yy; // just sample function
  }
}