public class AntiPodalAlgorithm {

  public static double findLargestDistance (Pointd[] points) {

    // 1. Compute the convex hull:
    Hull grahamHull = new Hull(points);

    // 2.0 Extract the hull points:
    Pointd[] hullPoints = grahamHull.getHull();

    // 2.1 Extract the number of points in the hull (hullSize):
    int hullSize = grahamHull.getSize();

    // variables to be used.
    double largest=0.0;
    int q0, q1, q2, i=0;

    // 3.0 Find the farthest point to size s0 of the hull
    //    incident at points[hullSize-1] and points[0]:
    while (Geometry.area(hullPoints[hullSize-1], hullPoints[0], hullPoints[i])
           < Geometry.area(hullPoints[hullSize-1], hullPoints[0], hullPoints[(i+1)%hullSize]))
      i++;
    q0 = i;

    // 3. Find farthest points to other sizes of the hull.
    //     Compute largest distance:
    for (int j=0; j<hullSize-1; j++) {

      // 3.1 Find farthest points:
      while (Geometry.area(hullPoints[j], hullPoints[j+1], hullPoints[i % hullSize])
           < Geometry.area(hullPoints[j], hullPoints[j+1], hullPoints[(i+1) % hullSize]))
        i++;
      q2 = i;
      q1 = i;

      // 3.2 Now the antipodal points of hullPoints[j] are between q0 and q1, inclusive.
      //     Compute the largest distance between antipodal pairs containing hullPoints[j]  
      while (!(q2<q0)) {
        largest = Math.max(largest,
          Geometry.distance(hullPoints[j], hullPoints[q2 % hullSize]));
        q2--;
      }
      q0 = q1;
    }

    return largest; 
  }

}