File DirectMap.h

namespace faiss

Implementation of k-means clustering with many variants.

Copyright (c) Facebook, Inc. and its affiliates.

This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree.

IDSelector is intended to define a subset of vectors to handle (for removal or as subset to search)

PQ4 SIMD packing and accumulation functions

The basic kernel accumulates nq query vectors with bbs = nb * 2 * 16 vectors and produces an output matrix for that. It is interesting for nq * nb <= 4, otherwise register spilling becomes too large.

The implementation of these functions is spread over 3 cpp files to reduce parallel compile times. Templates are instantiated explicitly.

This file contains callbacks for kernels that compute distances.

Throughout the library, vectors are provided as float * pointers. Most algorithms can be optimized when several vectors are processed (added/searched) together in a batch. In this case, they are passed in as a matrix. When n vectors of size d are provided as float * x, component j of vector i is

x[ i * d + j ]

where 0 <= i < n and 0 <= j < d. In other words, matrices are always compact. When specifying the size of the matrix, we call it an n*d matrix, which implies a row-major storage.

I/O functions can read/write to a filename, a file handle or to an object that abstracts the medium.

The read functions return objects that should be deallocated with delete. All references within these objectes are owned by the object.

Definition of inverted lists + a few common classes that implement the interface.

Since IVF (inverted file) indexes are of so much use for large-scale use cases, we group a few functions related to them in this small library. Most functions work both on IndexIVFs and IndexIVFs embedded within an IndexPreTransform.

In this file are the implementations of extra metrics beyond L2 and inner product

Implements a few neural net layers, mainly to support QINCo

Defines a few objects that apply transformations to a set of vectors Often these are pre-processing steps.

Functions

inline uint64_t lo_build(uint64_t list_id, uint64_t offset)

inline uint64_t lo_listno(uint64_t lo)

inline uint64_t lo_offset(uint64_t lo)

struct DirectMap

#include <DirectMap.h>

Direct map: a way to map back from ids to inverted lists

Public Types

enum Type

Values:

enumerator NoMap

enumerator Array

enumerator Hashtable

Public Functions

DirectMap()

void set_type(Type new_type, const InvertedLists *invlists, size_t ntotal)

set type and initialize

idx_t get(idx_t id) const

get an entry

inline bool no() const

for quick checks

void check_can_add(const idx_t *ids)

throw if Array and ids is not NULL

update the direct_map

void add_single_id(idx_t id, idx_t list_no, size_t offset)

non thread-safe version

void clear()

remove all entries

size_t remove_ids(const IDSelector &sel, InvertedLists *invlists)

remove ids from the InvertedLists, possibly using the direct map

operations on inverted lists that require translation with a DirectMap

void update_codes(InvertedLists *invlists, int n, const idx_t *ids, const idx_t *list_nos, const uint8_t *codes)

update entries, using the direct map

Public Members

Type type

std::vector<idx_t> array

map for direct access to the elements. Map ids to LO-encoded entries.

std::unordered_map<idx_t, idx_t> hashtable

struct DirectMapAdd

#include <DirectMap.h>

Thread-safe way of updating the direct_map.

Public Types

using Type = DirectMap::Type

Public Functions

DirectMapAdd(DirectMap &direct_map, size_t n, const idx_t *xids)

void add(size_t i, idx_t list_no, size_t offset)

add vector i (with id xids[i]) at list_no and offset

~DirectMapAdd()

Public Members

DirectMap &direct_map

DirectMap::Type type

size_t ntotal

size_t n

const idx_t *xids

std::vector<idx_t> all_ofs