blueflood-core/src/main/java/com/rackspacecloud/blueflood/types/BasicRollup.java
protected void computeFromSimpleMetrics(Points<SimpleNumber> input) throws IOException {

        super.computeFromSimpleMetrics( input );

        if (input.isEmpty()) {
            return;
        }

        Map<Long, Points.Point<SimpleNumber>> points = input.getPoints();
        for (Map.Entry<Long, Points.Point<SimpleNumber>> item : points.entrySet()) {
            SimpleNumber numericMetric = item.getValue().getData();
            sum += numericMetric.getValue().doubleValue();
        }
    }
protected void computeFromSimpleMetrics(Points<SimpleNumber> input) throws IOException {

        super.computeFromSimpleMetrics( input );

        if (input.isEmpty()) {
            return;
        }

        Map<Long, Points.Point<SimpleNumber>> points = input.getPoints();
        for (Map.Entry<Long, Points.Point<SimpleNumber>> item : points.entrySet()) {
            SimpleNumber numericMetric = item.getValue().getData();
            sum += numericMetric.getValue().doubleValue();
        }
    }
merge simple numbers with this rollup.