Class faiss::gpu::GpuIndexFlatL2

class GpuIndexFlatL2 : public faiss::gpu::GpuIndexFlat

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

Public Types

using component_t = float

using distance_t = float

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.

int getDevice() const

Returns the device that this index is resident on.

std::shared_ptr<GpuResources> getResources()

Returns a reference to our GpuResources object that manages memory, stream and handle resources on the GPU

void setMinPagingSize(size_t size)

Set the minimum data size for searches (in MiB) for which we use CPU -> GPU paging

size_t getMinPagingSize() const

Returns the current minimum data size for paged searches.

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

x and ids can be resident on the CPU or any GPU; copies are performed as needed Handles paged adds if the add set is too large; calls addInternal_

virtual void assign(idx_t n, const float *x, idx_t *labels, idx_t k = 1) const override

x and labels can be resident on the CPU or any GPU; copies are performed as needed

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

x, distances and labels can be resident on the CPU or any GPU; copies are performed as needed

virtual void search_and_reconstruct(idx_t n, const float *x, idx_t k, float *distances, idx_t *labels, float *recons, const SearchParameters *params = nullptr) const override

x, distances and labels and recons can be resident on the CPU or any GPU; copies are performed as needed

virtual void range_search(idx_t n, const float *x, float radius, RangeSearchResult *result, const SearchParameters *params = nullptr) const

query n vectors of dimension d to the index.

return all vectors with distance < radius. Note that many indexes do not implement the range_search (only the k-NN search is mandatory).

Parameters:

• n – number of vectors

• x – input vectors to search, size n * d

• radius – search radius

• result – result table

virtual size_t remove_ids(const IDSelector &sel)

removes IDs from the index. Not supported by all indexes. Returns the number of elements removed.

virtual DistanceComputer *get_distance_computer() const

Get a DistanceComputer (defined in AuxIndexStructures) object for this kind of index.

DistanceComputer is implemented for indexes that support random access of their vectors.

virtual size_t sa_code_size() const

size of the produced codes in bytes

virtual void sa_encode(idx_t n, const float *x, uint8_t *bytes) const

encode a set of vectors

Parameters:

• n – number of vectors

• x – input vectors, size n * d

• bytes – output encoded vectors, size n * sa_code_size()

virtual void sa_decode(idx_t n, const uint8_t *bytes, float *x) const

decode a set of vectors

Parameters:

• n – number of vectors

• bytes – input encoded vectors, size n * sa_code_size()

• x – output vectors, size n * d

virtual void merge_from(Index &otherIndex, idx_t add_id = 0)

moves the entries from another dataset to self. On output, other is empty. add_id is added to all moved ids (for sequential ids, this would be this->ntotal)

virtual void check_compatible_for_merge(const Index &otherIndex) const

check that the two indexes are compatible (ie, they are trained in the same way and have the same parameters). Otherwise throw.

virtual void add_sa_codes(idx_t n, const uint8_t *codes, const idx_t *xids)

Add vectors that are computed with the standalone codec

Parameters:

• codes – codes to add size n * sa_code_size()

• xids – corresponding ids, size n

Public Members

int d

vector dimension

idx_t ntotal

total nb of indexed vectors

bool verbose

verbosity level

bool is_trained

set if the Index does not require training, or if training is done already

MetricType metric_type

type of metric this index uses for search

float metric_arg

argument of the metric type

Protected Functions

void copyFrom(const faiss::Index *index)

Copy what we need from the CPU equivalent.

void copyTo(faiss::Index *index) const

Copy what we have to the CPU equivalent.

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.

std::shared_ptr<GpuResources> resources_

Manages streams, cuBLAS handles and scratch memory for devices.

const GpuIndexConfig config_

Our configuration options.

size_t minPagedSize_

Size above which we page copies from the CPU to GPU.