public double distanceSq(Vector other){
  return Math.pow(other.x - x,2) + Math.pow(other.y - y,2) + Math.pow(other.z - z,2);
}

public double distanceSq ( Vector other ) { return Math . pow ( other . x - x , 2 ) + Math . pow ( other . y - y , 2 ) + Math . pow ( other . z - z , 2 ) ; }
get the distance between this vector and another vector , squared .
