double n = FastMath.sqrt(norm()); x /= n; y /= n; z /= n; w /= n;
float n = FastMath.invSqrt(norm()); x *= n; y *= n; z *= n; w *= n;
    public void normalize() {        double n = FastMath.sqrt(norm());        x /= n;        y /= n;        z /= n;        w /= n;    }