docs: @Pure
  	public final double getAngle() {
  		double mag = this.x*this.x + this.y*this.y + this.z*this.z;  
  
  		if ( mag > EPS ) {
  			mag = Math.sqrt(mag);
  			return (2.f*Math.atan2(mag, this.w)); 
  		}
  		return 0f;
  	}