if (SIRassignment == null) return null; return (Coordinate)SIRassignment.get(str);
if (layout.SIRassignment == null) return null; return (Coordinate)layout.SIRassignment.get(str);
    public static Coordinate getTile(SIROperator str)     {	if (SIRassignment == null) return null;	return (Coordinate)SIRassignment.get(str);    }