Multiple threshold for Multilabel metrics

[ding3820]

🚀 Feature

Allow multiple thresholds for every multilabel metrics

Motivation

I notice that for every multilabel metrics, threshold only allows a float. In some cases, we would like to use different threshold for different class.

Pitch

For example: mla = MultilabelAccuracy(threshold=[0.3, 0.7, 0.55], num_labels=3, average=None)

Alternatives

Additional context