A curve indicating the percentage of points that are mild in- and extrusions
or keep their rank.

## Arguments

- Q
a co-ranking matrix

## Value

A vector with the values for Q_NX(K)

## Details

$$ Q_{NX}(K) = \frac{1}{KN} \sum_{k=1}^{K}\sum_{l=1}^{K}Q_{kl} $$

## References

Lueks, W., Mokbel, B., Biehl, M., & Hammer, B. (2011). How to
Evaluate Dimensionality Reduction? - Improving the Co-ranking Matrix.
ArXiv:1110.3917 [Cs]. http://arxiv.org/abs/1110.3917