Update IDSelector to support vector filtering by distance

[jaepil]

Currently, there is no way to select vectors using distance with IDSelector. This PR adds overloaded version of is_member(idx, [d]) function to IDSelector, so the user can make a decision based on the distance.

Let me know, if Faiss already supports similar functionality in different ways.

[mnorris11]

Hi @jaepil , sorry for the delay. I took a look through it.

Is range_search not suitable to your use case? (guessing you are interested mainly in HNSW given it was updated in the PR, so range_search for HNSW is found at

faiss/faiss/IndexHNSW.cpp

Line 336 in 749163e

void IndexHNSW::range_search(

)

If range_search is not right here, my first questions are:

1. Can you share more info on why you need distance for your use case?
2. Can you add a unit test demonstrating/testing it?
3. Is this applicable for other indexes besides HNSW?

[mnorris11]

Closing PR at team's request. But if range_search is not suitable, please reach out / reopen.

Adding some more details:

• IDSelector's purpose is to just select based on ids.
• To customize more it’s still possible to implement a custom result collector (now known as Result Handler) for HNSW. For context, Generalize ResultHanlder, support range search for HNSW and Fast Scan #3190 may be useful. You can inherit from ResultHandler at

  faiss/faiss/impl/ResultHandler.h

  Line 72 in 0363934

  struct ResultHandler {

  and that can be passed in to hnsw’s search https://github.com/facebookresearch/faiss/blob/main/faiss/impl/HNSW.h#L201.