code: public void scale(double s, Vector3d v1) {
          x = s * v1.x;
          y = s * v1.y;
          z = s * v1.z;
      }
docs: Scales the elements of vector v1 by <code>s</code> and places the results
  in this vector.
  
  @param s
  scaling factor
  @param v1
  vector to be scaled