Struct faiss::InvertedListScanner

struct InvertedListScanner

Object that handles a query. The inverted lists to scan are provided externally. The object has a lot of state, but distance_to_code and scan_codes can be called in multiple threads

Public Functions

inline InvertedListScanner(bool store_pairs = false, const IDSelector *sel = nullptr)

virtual void set_query(const float *query_vector) = 0: from now on we handle this query.

virtual void set_list(idx_t list_no, float coarse_dis) = 0: following codes come from this inverted list

virtual float distance_to_code(const uint8_t *code) const = 0: compute a single query-to-code distance

virtual size_t scan_codes(size_t n, const uint8_t *codes, const idx_t *ids, float *distances, idx_t *labels, size_t k) const

scan a set of codes, compute distances to current query and update heap of results if necessary. Default implementation calls distance_to_code.

Parameters:

n – number of codes to scan
codes – codes to scan (n * code_size)
ids – corresponding ids (ignored if store_pairs)
distances – heap distances (size k)
labels – heap labels (size k)
k – heap size

Returns:

number of heap updates performed

virtual size_t iterate_codes(InvertedListsIterator *iterator, float *distances, idx_t *labels, size_t k, size_t &list_size) const

virtual void scan_codes_range(size_t n, const uint8_t *codes, const idx_t *ids, float radius, RangeQueryResult &result) const

scan a set of codes, compute distances to current query and update results if distances are below radius

(default implementation fails)

virtual void iterate_codes_range(InvertedListsIterator *iterator, float radius, RangeQueryResult &result, size_t &list_size) const

inline virtual ~InvertedListScanner()

Public Members

idx_t list_no = -1: remember current list

bool keep_max = false: keep maximum instead of minimum

bool store_pairs: store positions in invlists rather than labels

const IDSelector *sel: search in this subset of ids

size_t code_size = 0: used in default implementation of scan_codes