docs: public final void inverse() {
  		double norm;  
  
  		norm = 1f/(this.w*this.w + this.x*this.x + this.y*this.y + this.z*this.z);
  		this.w *=  norm;
  		this.x *= -norm;
  		this.y *= -norm;
  		this.z *= -norm;
  	}