LPKY distance measure

[Fernando Alves]

Hi,

Does anyone know how to change the distance measure used for knn in the user knn?

Thanks

Best regards

Fernando

[Michael Ekstrand]

Fernando,

Unfortunately, the user KNN algorithm is not very reconfigurable. In LKPY we have de-emphasized the extensive configurability of the previous version of LensKit in favor of algorithms that work pretty well out of the box. Cosine similarity over normalized vectors seems to work at least as well as any of the other common configurations (https://grouplens.org/blog/similarity-functions-for-user-user-collaborative-filtering/), so we just do that, and it gives us substantial performance benefits.

I would entertain pull requests to add generalized / configurable neighborhood models, but it hasn't been a development priority.

- Michael

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Michael D. Ekstrand — michael...@boisestate.edu — https://md.ekstrandom.net
Assistant Professor, Dept. of Computer Science, Boise State University

People and Information Research Team (PIReT) — http://coen.boisestate.edu/piret/

[Fernando Alves]

Aye, thanks.