Add the metric AUC

[miguelgfierro]

This can be used by any algo that implemented regression metrics

[yueguoguo]

To clarify, AUC is meant for binary classification, right? Probably this would be useful to the content-based algorithms for predicting hit/not-hit?

[miguelgfierro]

yes, that's exactly the reason. It was used in xDeepFM

[miguelgfierro]

Metrics to implement:

• limited AUC
• average AUC
• direct AUC from sklearn