Function faiss_IDSelectorBatch_nbits 

pub unsafe extern "C" fn faiss_IDSelectorBatch_nbits(
    arg1: *const FaissIDSelectorBatch,
) -> c_int

Remove ids from a set. Repetitions of ids in the indices set passed to the constructor does not hurt performance. The hash function used for the bloom filter and GCC’s implementation of unordered_set are just the least significant bits of the id. This works fine for random ids or ids in sequences but will produce many hash collisions if lsb’s are always the same