File GpuIndexFlat.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.

namespace gpu

struct GpuIndexFlatConfig : public faiss::gpu::GpuIndexConfig

Public Functions

bool ALIGNED (8) useFloat16

Whether or not data is stored as float16.

Public Members

bool storeTransposed = false

Deprecated: no longer used Previously used to indicate whether internal storage of vectors is transposed

class GpuIndexFlat : public faiss::gpu::GpuIndex

#include <GpuIndexFlat.h>

Wrapper around the GPU implementation that looks like faiss::IndexFlat; copies over centroid data from a given faiss::IndexFlat

Subclassed by faiss::gpu::GpuIndexFlatIP, faiss::gpu::GpuIndexFlatL2

Public Functions

GpuIndexFlat(GpuResourcesProvider *provider, const faiss::IndexFlat *index, GpuIndexFlatConfig config = GpuIndexFlatConfig())

Construct from a pre-existing faiss::IndexFlat instance, copying data over to the given GPU

GpuIndexFlat(std::shared_ptr<GpuResources> resources, const faiss::IndexFlat *index, GpuIndexFlatConfig config = GpuIndexFlatConfig())

GpuIndexFlat(GpuResourcesProvider *provider, int dims, faiss::MetricType metric, GpuIndexFlatConfig config = GpuIndexFlatConfig())

Construct an empty instance that can be added to.

GpuIndexFlat(std::shared_ptr<GpuResources> resources, int dims, faiss::MetricType metric, GpuIndexFlatConfig config = GpuIndexFlatConfig())

~GpuIndexFlat() override

void copyFrom(const faiss::IndexFlat *index)

Initialize ourselves from the given CPU index; will overwrite all data in ourselves

void copyTo(faiss::IndexFlat *index) const

Copy ourselves to the given CPU index; will overwrite all data in the index instance

size_t getNumVecs() const

Returns the number of vectors we contain.

virtual void reset() override

Clears all vectors from this index.

virtual void train(idx_t n, const float *x) override

This index is not trained, so this does nothing.

virtual void add(idx_t, const float *x) override

Overrides to avoid excessive copies.

virtual void reconstruct(idx_t key, float *out) const override

Reconstruction methods; prefer the batch reconstruct as it will be more efficient

virtual void reconstruct_n(idx_t i0, idx_t num, float *out) const override

Batch reconstruction method.

virtual void reconstruct_batch(idx_t n, const idx_t *keys, float *out) const override

Batch reconstruction method.

virtual void compute_residual(const float *x, float *residual, idx_t key) const override

Compute residual.

virtual void compute_residual_n(idx_t n, const float *xs, float *residuals, const idx_t *keys) const override

Compute residual (batch mode)

inline FlatIndex *getGpuData()

For internal access.

Protected Functions

void resetIndex_(int dims)

virtual bool addImplRequiresIDs_() const override

Flat index does not require IDs as there is no storage available for them

virtual void addImpl_(idx_t n, const float *x, const idx_t *ids) override

Called from GpuIndex for add.

virtual void searchImpl_(idx_t n, const float *x, int k, float *distances, idx_t *labels, const SearchParameters *params) const override

Called from GpuIndex for search.

Protected Attributes

const GpuIndexFlatConfig flatConfig_

Our configuration options.

std::unique_ptr<FlatIndex> data_

Holds our GPU data containing the list of vectors.

class GpuIndexFlatL2 : public faiss::gpu::GpuIndexFlat

#include <GpuIndexFlat.h>

Wrapper around the GPU implementation that looks like faiss::IndexFlatL2; copies over centroid data from a given faiss::IndexFlat

Public Functions

GpuIndexFlatL2(GpuResourcesProvider *provider, faiss::IndexFlatL2 *index, GpuIndexFlatConfig config = GpuIndexFlatConfig())

Construct from a pre-existing faiss::IndexFlatL2 instance, copying data over to the given GPU

GpuIndexFlatL2(std::shared_ptr<GpuResources> resources, faiss::IndexFlatL2 *index, GpuIndexFlatConfig config = GpuIndexFlatConfig())

GpuIndexFlatL2(GpuResourcesProvider *provider, int dims, GpuIndexFlatConfig config = GpuIndexFlatConfig())

Construct an empty instance that can be added to.

GpuIndexFlatL2(std::shared_ptr<GpuResources> resources, int dims, GpuIndexFlatConfig config = GpuIndexFlatConfig())

void copyFrom(faiss::IndexFlat *index)

Initialize ourselves from the given CPU index; will overwrite all data in ourselves

void copyTo(faiss::IndexFlat *index)

Copy ourselves to the given CPU index; will overwrite all data in the index instance

void copyFrom(const faiss::IndexFlat *index)

Initialize ourselves from the given CPU index; will overwrite all data in ourselves

void copyTo(faiss::IndexFlat *index) const

Copy ourselves to the given CPU index; will overwrite all data in the index instance

size_t getNumVecs() const

Returns the number of vectors we contain.

virtual void reset() override

Clears all vectors from this index.

virtual void train(idx_t n, const float *x) override

This index is not trained, so this does nothing.

virtual void add(idx_t, const float *x) override

Overrides to avoid excessive copies.

virtual void reconstruct(idx_t key, float *out) const override

Reconstruction methods; prefer the batch reconstruct as it will be more efficient

virtual void reconstruct_n(idx_t i0, idx_t num, float *out) const override

Batch reconstruction method.

virtual void reconstruct_batch(idx_t n, const idx_t *keys, float *out) const override

Batch reconstruction method.

virtual void compute_residual(const float *x, float *residual, idx_t key) const override

Compute residual.

virtual void compute_residual_n(idx_t n, const float *xs, float *residuals, const idx_t *keys) const override

Compute residual (batch mode)

inline FlatIndex *getGpuData()

For internal access.

Protected Functions

void resetIndex_(int dims)

virtual bool addImplRequiresIDs_() const override

Flat index does not require IDs as there is no storage available for them

virtual void addImpl_(idx_t n, const float *x, const idx_t *ids) override

Called from GpuIndex for add.

virtual void searchImpl_(idx_t n, const float *x, int k, float *distances, idx_t *labels, const SearchParameters *params) const override

Called from GpuIndex for search.

Protected Attributes

const GpuIndexFlatConfig flatConfig_

Our configuration options.

std::unique_ptr<FlatIndex> data_

Holds our GPU data containing the list of vectors.

class GpuIndexFlatIP : public faiss::gpu::GpuIndexFlat

#include <GpuIndexFlat.h>

Wrapper around the GPU implementation that looks like faiss::IndexFlatIP; copies over centroid data from a given faiss::IndexFlat

Public Functions

GpuIndexFlatIP(GpuResourcesProvider *provider, faiss::IndexFlatIP *index, GpuIndexFlatConfig config = GpuIndexFlatConfig())

Construct from a pre-existing faiss::IndexFlatIP instance, copying data over to the given GPU

GpuIndexFlatIP(std::shared_ptr<GpuResources> resources, faiss::IndexFlatIP *index, GpuIndexFlatConfig config = GpuIndexFlatConfig())

GpuIndexFlatIP(GpuResourcesProvider *provider, int dims, GpuIndexFlatConfig config = GpuIndexFlatConfig())

Construct an empty instance that can be added to.

GpuIndexFlatIP(std::shared_ptr<GpuResources> resources, int dims, GpuIndexFlatConfig config = GpuIndexFlatConfig())

void copyFrom(faiss::IndexFlat *index)

Initialize ourselves from the given CPU index; will overwrite all data in ourselves

void copyTo(faiss::IndexFlat *index)

Copy ourselves to the given CPU index; will overwrite all data in the index instance

void copyFrom(const faiss::IndexFlat *index)

Initialize ourselves from the given CPU index; will overwrite all data in ourselves

void copyTo(faiss::IndexFlat *index) const

Copy ourselves to the given CPU index; will overwrite all data in the index instance

size_t getNumVecs() const

Returns the number of vectors we contain.

virtual void reset() override

Clears all vectors from this index.

virtual void train(idx_t n, const float *x) override

This index is not trained, so this does nothing.

virtual void add(idx_t, const float *x) override

Overrides to avoid excessive copies.

virtual void reconstruct(idx_t key, float *out) const override

Reconstruction methods; prefer the batch reconstruct as it will be more efficient

virtual void reconstruct_n(idx_t i0, idx_t num, float *out) const override

Batch reconstruction method.

virtual void reconstruct_batch(idx_t n, const idx_t *keys, float *out) const override

Batch reconstruction method.

virtual void compute_residual(const float *x, float *residual, idx_t key) const override

Compute residual.

virtual void compute_residual_n(idx_t n, const float *xs, float *residuals, const idx_t *keys) const override

Compute residual (batch mode)

inline FlatIndex *getGpuData()

For internal access.

Protected Functions

void resetIndex_(int dims)

virtual bool addImplRequiresIDs_() const override

Flat index does not require IDs as there is no storage available for them

virtual void addImpl_(idx_t n, const float *x, const idx_t *ids) override

Called from GpuIndex for add.

virtual void searchImpl_(idx_t n, const float *x, int k, float *distances, idx_t *labels, const SearchParameters *params) const override

Called from GpuIndex for search.

Protected Attributes

const GpuIndexFlatConfig flatConfig_

Our configuration options.

std::unique_ptr<FlatIndex> data_

Holds our GPU data containing the list of vectors.