Attention weights in TransformerConv

[VaniOFX]

Hi Matt, I was wondering if there is a reason why TransformerConv does not have a return_attention_weights just like GATConv? What do you think would be the easiest way to get the attention scores for the edges?

[wsad1]

I guess one way would be to implement a return_attention_weights functionality. Another simple hack would be to add this line self.alpha=alpha to the message function in TransformerConv, and get alpha from the object of TransformerConv after calling forward.

[rusty1s]

Yes, I think we should definitely provide such functionality. Putting it on the roadmap.

[rusty1s]

Fixed in #2807 thanks to @wsad1