blueflood-core/src/main/java/com/rackspacecloud/blueflood/rollup/Granularity.java
private static Granularity granularityFromPointsLessThanEqual(double requestedDuration, int points, long assumedIntervalMillis) {
        Granularity gran = granularityFromPointsLinear(requestedDuration, points, assumedIntervalMillis);

        if (requestedDuration / gran.milliseconds() > points) {
            try {
                gran = gran.coarser();
            } catch (GranularityException e) { /* do nothing, already at 1440m */ }
        }

        return gran;
    }
private static Granularity granularityFromPointsLessThanEqual(double requestedDuration, int points, long assumedIntervalMillis) {
        Granularity gran = granularityFromPointsLinear(requestedDuration, points, assumedIntervalMillis);

        if (requestedDuration / gran.milliseconds() > points) {
            try {
                gran = gran.coarser();
            } catch (GranularityException e) { /* do nothing, already at 1440m */ }
        }

        return gran;
    }
Find the granularity in the interval that will yield a number of data points that are
closest to the requested points but <= requested points.

@param requestedDuration
@param points
@return