for _, n := range ns {
				score[n] = n.Cum
			}
			s = nodeSorter{ns, scoreOrder}
		case EntropyOrder:
			score = make(map[*Node]int64, len(ns))
			for _, n := range ns {
				score[n] = entropyScore(n)
			}
			s = nodeSorter{ns, scoreOrder}
		}
	default:
		return fmt.Errorf("report: unrecognized sort ordering: %d", o)
	}
	sort.Sort(s)
	return nil
}