public TreeSet get2DCombos() {
        TreeSet params = new TreeSet();

        for (Iterator i = parameters.keySet().iterator(); i.hasNext();) {
            Parameter p = (Parameter)(parameters.get(i.next()));
            if (p.getNumDim()== 2) {
                String foo = p.getDimension(0).getName() + "," + p.getDimension(1).getName();
                params.add(foo);
            }
        }
        return (params);
    }