Multi-label classification support

[aaarrti]

Description of the problem

• afaik so far, Quantus assumes categorical encoding of y_batch, where each input data-point is assigned to exactly 1 label.

Description of a solution

• Investigate possibilities to support multi-label classification.
• Add tutorial showcasing multi-label classification.

[JonasKlotz]

Is this issue still relevant? Currently, I'm working on my master thesis in XAI and MLC. For the evaluation I've forked Quantus and started to implement some very basic MLC support. My current design choices are strongly based on my own use-case, but if you are interested we could discuss your requirements to make these changes public.

I can keep you updated on my progress and write a more detailed description of my approach if you want.