Method saddle

src/org/opensourcephysics/display2d/TestData.java:41–44

Saddle function centered at x=0 and y=0.

(double x, double y)

   * Saddle function centered at x=0 and y=0.
   */
  public static double saddle(double x, double y) {
    double rSqr = x*x-y*y;
    return Math.exp(rSqr);
  }

  /**
   * Generate a dipole scalar field.