Comment by montebicyclelo

The author asks:

> Has the model ever seen cosine similarity?

Yes - most of the time, at least for deep learning based semantic search. E.g. for semantic search of text, the majority are using, SentenceTransformers [1], models which have been trained to use cosine similarity. Or e.g. for vector representations of images, people are using models like CLIP [2], which has again been trained to use cosine similarity. (Cosine similarity being used in the training loss, so the whole model is fundamentally "tuned" for cosine similarity.)

Articles like these cause confusion, e.g. I've come across people saying: "You shouldn't use cosine similarity", when they've seen SentenceTransformers being used, and linking articles like these, when in fact you very much should be using cosine similarity with those models.

[1] https://sbert.net

[2] https://arxiv.org/abs/2103.00020