public int compareDescendWeight(Object o) {
        PredictedTopic pt = (PredictedTopic)o;

        double wgt1 = getWeight();
        double wgt2 = pt.getWeight();
        if (wgt1 < wgt2) { return 1; }
        if (wgt1 > wgt2) { return -1;}
        return 0;
    }
Compares this topic to another topic, according to weight descending
fsa/src/main/java/com/yahoo/fsa/topicpredictor/PredictedTopic.java