#include <IndexIVF.h>

Inheritance diagram for faiss::IndexIVF:

Public Member Functions
	IndexIVF (Index *quantizer, size_t d, size_t nlist, MetricType metric=METRIC_INNER_PRODUCT)

virtual void	reset () override
	removes all elements from the database.

virtual void	train (idx_t n, const float *x) override
	Trains the quantizer and calls train_residual to train sub-quantizers.

virtual void	add (idx_t n, const float *x) override
	Quantizes x and calls add_with_key.

virtual void	train_residual (idx_t n, const float *x)

virtual void	merge_from (IndexIVF &other, idx_t add_id)

virtual void	merge_from_residuals (IndexIVF &other)=0

void	make_direct_map ()
	intialize a direct map

double	imbalance_factor () const
	1= perfectly balanced, >1: imbalanced

void	print_stats () const
	display some stats about the inverted lists

Public Member Functions inherited from faiss::Index
	Index (idx_t d=0, MetricType metric=METRIC_INNER_PRODUCT)

virtual void	add_with_ids (idx_t n, const float x, const long xids)

virtual void	search (idx_t n, const float x, idx_t k, float distances, idx_t *labels) const =0

virtual void	range_search (idx_t n, const float x, float radius, RangeSearchResult result) const

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

virtual long	remove_ids (const IDSelector &sel)

virtual void	reconstruct (idx_t key, float *recons) const

virtual void	reconstruct_n (idx_t i0, idx_t ni, float *recons) const

void	compute_residual (const float x, float residual, idx_t key) const

void	display () const

virtual std::string	get_typename () const

virtual void	set_typename ()=0

Public Attributes
size_t	nlist
	number of possible key values

size_t	nprobe
	number of probes at query time

Index *	quantizer
	quantizer that maps vectors to inverted lists

bool	quantizer_trains_alone
	just pass over the trainset to quantizer

bool	own_fields
	whether object owns the quantizer

ClusteringParameters	cp
	to override default clustering params

std::vector< std::vector< long > >	ids
	Inverted lists for indexes.

bool	maintain_direct_map
	map for direct access to the elements. Enables reconstruct().

std::vector< long >	direct_map

Public Attributes inherited from faiss::Index
std::string	index_typename

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

Additional Inherited Members
Public Types inherited from faiss::Index
typedef long	idx_t
	all indices are this type

Detailed Description

Index based on a inverted file (IVF)

In the inverted file, the quantizer (an Index instance) provides a quantization index for each vector to be added. The quantization index maps to a list (aka inverted list or posting list), where the id of the vector is then stored.

At search time, the vector to be searched is also quantized, and only the list corresponding to the quantization index is searched. This speeds up the search by making it non-exhaustive. This can be relaxed using multi-probe search: a few (nprobe) quantization indices are selected and several inverted lists are visited.

Sub-classes implement a post-filtering of the index that refines the distance estimation from the query to databse vectors.

Definition at line 46 of file IndexIVF.h.

Constructor & Destructor Documentation

faiss::IndexIVF::IndexIVF	(	Index *	quantizer,
		size_t	d,
		size_t	nlist,
		MetricType	metric = `METRIC_INNER_PRODUCT`
	)

The Inverted file takes a quantizer (an Index) on input, which implements the function mapping a vector to a list identifier. The pointer is borrowed: the quantizer should not be deleted while the IndexIVF is in use.

Definition at line 32 of file IndexIVF.cpp.

Member Function Documentation

void faiss::IndexIVF::merge_from	(	IndexIVF &	other,
		idx_t	add_id
	)

virtual

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

Definition at line 163 of file IndexIVF.cpp.

virtual void faiss::IndexIVF::merge_from_residuals ( IndexIVF & other )

pure virtual

implemented by sub-classes

Implemented in faiss::IndexIVFPQR, faiss::IndexIVFFlat, and faiss::IndexIVFPQ.

void faiss::IndexIVF::train_residual	(	idx_t	n,
		const float *	x
	)

virtual

Sub-classes that encode the residuals can train their encoders here does nothing by default

Reimplemented in faiss::IndexIVFPQR, and faiss::IndexIVFPQ.

Definition at line 125 of file IndexIVF.cpp.

The documentation for this struct was generated from the following files:

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation