/** insert in a triangle the barycenter point of its incident vertices */
public void insertBarycenter(TriangulationDSFace_2<X> f) {
if (f == null) throw new Error("null face error");
Point_[] points = f.verticesPoints();
Point_ newPoint = new Point_2();
newPoint.barycenter(points);
this.insertInTriangle((X) newPoint, f);
}
