File IndexReplicas.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.

Typedefs

using IndexReplicas = IndexReplicasTemplate<Index>
using IndexBinaryReplicas = IndexReplicasTemplate<IndexBinary>
template<typename IndexT>
class IndexReplicasTemplate : public faiss::ThreadedIndex<IndexT>
#include <IndexReplicas.h>

Takes individual faiss::Index instances, and splits queries for sending to each Index instance, and joins the results together when done. Each index is managed by a separate CPU thread.

Public Types

using component_t = typename IndexT::component_t
using distance_t = typename IndexT::distance_t

Public Functions

explicit IndexReplicasTemplate(bool threaded = true)

The dimension that all sub-indices must share will be the dimension of the first sub-index added

Parameters:

threaded – do we use one thread per sub-index or do queries sequentially?

explicit IndexReplicasTemplate(idx_t d, bool threaded = true)
Parameters:
  • d – the dimension that all sub-indices must share

  • threaded – do we use one thread per sub index or do queries sequentially?

explicit IndexReplicasTemplate(int d, bool threaded = true)

int version due to the implicit bool conversion ambiguity of int as dimension

inline void add_replica(IndexT *index)

Alias for addIndex()

inline void remove_replica(IndexT *index)

Alias for removeIndex()

void train(idx_t n, const component_t *x) override

faiss::Index API All indices receive the same call

void add(idx_t n, const component_t *x) override

faiss::Index API All indices receive the same call

void search(idx_t n, const component_t *x, idx_t k, distance_t *distances, idx_t *labels, const SearchParameters *params = nullptr) const override

faiss::Index API Query is partitioned into a slice for each sub-index split by ceil(n / #indices) for our sub-indices

void reconstruct(idx_t, component_t *v) const override

reconstructs from the first index

void syncWithSubIndexes()

Synchronize the top-level index (IndexShards) with data in the sub-indices

Protected Functions

virtual void onAfterAddIndex(IndexT *index) override

Called just after an index is added.

virtual void onAfterRemoveIndex(IndexT *index) override

Called just after an index is removed.