Classes
struct	MinimaxHeap

struct	NodeDistCloser
	to sort pairs of (id, distance) from nearest to fathest or the reverse More...

struct	NodeDistFarther

Public Types
typedef int	storage_idx_t
	internal storage of vectors (32 bits: this is expensive)

typedef Index::idx_t	idx_t
	Faiss results are 64-bit.

typedef std::pair< float, storage_idx_t >	Node

Public Member Functions
void	set_default_probas (int M, float levelMult)

void	set_nb_neighbors (int level_no, int n)
	set nb of neighbors for this level (before adding anything)

int	nb_neighbors (int layer_no) const
	nb of neighbors for this level

int	cum_nb_neighbors (int layer_no) const
	cumumlative nb up to (and excluding) this level

void	neighbor_range (idx_t no, int layer_no, size_t begin, size_t end) const
	range of entries in the neighbors table of vertex no at layer_no

	HNSW (int M=32)
	only mandatory parameter: nb of neighbors

int	random_level ()
	pick a random level for a new point

void	fill_with_random_links (size_t n)
	add n random levels to table (for debugging...)

void	add_links_starting_from (DistanceComputer &ptdis, storage_idx_t pt_id, storage_idx_t nearest, float d_nearest, int level, omp_lock_t *locks, VisitedTable &vt)

void	add_with_locks (DistanceComputer &ptdis, int pt_level, int pt_id, std::vector< omp_lock_t > &locks, VisitedTable &vt)

int	search_from_candidates (DistanceComputer &qdis, int k, idx_t I, float D, MinimaxHeap &candidates, VisitedTable &vt, int level, int nres_in=0) const

std::priority_queue< Node >	search_from_candidate_unbounded (const Node &node, DistanceComputer &qdis, int ef, VisitedTable *vt) const

void	search (DistanceComputer &qdis, int k, idx_t I, float D, VisitedTable &vt) const
	search interface

void	reset ()

void	clear_neighbor_tables (int level)

void	print_neighbor_stats (int level) const

int	prepare_level_tab (size_t n, bool preset_levels=false)

Static Public Member Functions
static void	shrink_neighbor_list (DistanceComputer &qdis, std::priority_queue< NodeDistFarther > &input, std::vector< NodeDistFarther > &output, int max_size)

Public Attributes
std::vector< double >	assign_probas
	assignment probability to each layer (sum=1)

std::vector< int >	cum_nneighbor_per_level

std::vector< int >	levels
	level of each vector (base level = 1), size = ntotal

std::vector< size_t >	offsets

std::vector< storage_idx_t >	neighbors

storage_idx_t	entry_point
	entry point in the search structure (one of the points with maximum level

faiss::RandomGenerator	rng

int	max_level
	maximum level

int	efConstruction
	expansion factor at construction time

int	efSearch
	expansion factor at search time

bool	check_relative_distance = true
	during search: do we check whether the next best distance is good enough?

int	upper_beam
	number of entry points in levels > 0.

bool	search_bounded_queue = true
	use bounded queue during exploration

Detailed Description

Definition at line 46 of file HNSW.h.

Member Function Documentation

void faiss::HNSW::add_links_starting_from	(	DistanceComputer &	ptdis,
		storage_idx_t	pt_id,
		storage_idx_t	nearest,
		float	d_nearest,
		int	level,
		omp_lock_t *	locks,
		VisitedTable &	vt
	)

Finds neighbors and builds links with them, starting from an entry point. The own neighbor list is assumed to be locked.

Definition at line 441 of file HNSW.cpp.

void faiss::HNSW::add_with_locks	(	DistanceComputer &	ptdis,
		int	pt_level,
		int	pt_id,
		std::vector< omp_lock_t > &	locks,
		VisitedTable &	vt
	)

add point pt_id on all levels <= pt_level and build the link structure for them.

Definition at line 477 of file HNSW.cpp.

int faiss::HNSW::search_from_candidates	(	DistanceComputer &	qdis,
		int	k,
		idx_t *	I,
		float *	D,
		MinimaxHeap &	candidates,
		VisitedTable &	vt,
		int	level,
		int	nres_in = `0`
	)		const

Do a BFS on the candidates list

Definition at line 523 of file HNSW.cpp.

void faiss::HNSW::set_default_probas	(	int	M,
		float	levelMult
	)

initialize the assign_probas and cum_nneighbor_per_level to have 2*M links on level 0 and M links on levels > 0

Definition at line 76 of file HNSW.cpp.

void faiss::HNSW::shrink_neighbor_list	(	DistanceComputer &	qdis,
		std::priority_queue< NodeDistFarther > &	input,
		std::vector< NodeDistFarther > &	output,
		int	max_size
	)

static

Enumerate vertices from farthest to nearest from query, keep a neighbor only if there is no previous neighbor that is closer to that vertex than the query.

Definition at line 235 of file HNSW.cpp.

Member Data Documentation

std::vector<int> faiss::HNSW::cum_nneighbor_per_level

number of neighbors stored per layer (cumulative), should not be changed after first add

Definition at line 103 of file HNSW.h.

std::vector<storage_idx_t> faiss::HNSW::neighbors

neighbors[offsets[i]:offsets[i+1]] is the list of neighbors of vector i for all levels. this is where all storage goes.

Definition at line 114 of file HNSW.h.

std::vector<size_t> faiss::HNSW::offsets

offsets[i] is the offset in the neighbors array where vector i is stored size ntotal + 1

Definition at line 110 of file HNSW.h.

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

/data/users/hoss/faiss/HNSW.h
/data/users/hoss/faiss/HNSW.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Detailed Description

Member Function Documentation

Member Data Documentation