RN_X curveArea under the \(R_{NX}(K)\) curve when \(K\) is put on a logarithmic scale.
AUC_ln_K(R_NX)A value, the area under the curve.
The R_NX curve, a vector of values
Guido Kraemer
It is calculated as: $$ AUC_{\ln K}(R_{NX}(K)) = \left(\sum_{K=1}^{N-2}R_{NX}(K)/K\right)/\left(\sum_{K=1}^{N-2}1/K\right) $$
Lee, J. A., Peluffo-Ordóñez, D. H., & Verleysen, M., 2015. Multi-scale similarities in stochastic neighbour embedding: Reducing dimensionality while preserving both local and global structure. Neurocomputing, 169, 246–261. https://doi.org/10.1016/j.neucom.2014.12.095