nanoflann
C++ header-only ANN library
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nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t > Class Template Reference

#include <nanoflann.hpp>

Inheritance diagram for nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >:
nanoflann::KDTreeBaseClass< KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t >, Distance, DatasetAdaptor, -1, uint32_t >

Public Types

using Base
using Offset = typename Base::Offset
using Size = typename Base::Size
using Dimension = typename Base::Dimension
using ElementType = typename Base::ElementType
using DistanceType = typename Base::DistanceType
using IndexType = typename Base::IndexType
using Node = typename Base::Node
using NodePtr = Node*
using Interval = typename Base::Interval
using BoundingBox = typename Base::BoundingBox
using distance_vector_t = typename Base::distance_vector_t
Public Types inherited from nanoflann::KDTreeBaseClass< KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t >, Distance, DatasetAdaptor, -1, uint32_t >
using ElementType
using DistanceType
using IndexType
using Offset
using Size
using Dimension
using NodePtr
using NodeConstPtr
using BoundingBox
using distance_vector_t

Public Member Functions

 KDTreeSingleIndexAdaptor (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t > &)=delete
template<class... Args>
 KDTreeSingleIndexAdaptor (const Dimension dimensionality, const DatasetAdaptor &inputData, const KDTreeSingleIndexAdaptorParams &params, Args &&... args)
 KDTreeSingleIndexAdaptor (const Dimension dimensionality, const DatasetAdaptor &inputData, const KDTreeSingleIndexAdaptorParams &params={})
void buildIndex ()
void init_vind ()
bool contains (const BoundingBox &bbox, IndexType idx) const
void saveIndex (std::ostream &stream) const
void loadIndex (std::istream &stream)
Query methods
template<typename RESULTSET>
bool findNeighbors (RESULTSET &result, const ElementType *vec, const SearchParameters &searchParams={}) const
template<typename RESULTSET>
NANOFLANN_NODISCARD Size findWithinBox (RESULTSET &result, const BoundingBox &bbox) const
NANOFLANN_NODISCARD Size knnSearch (const ElementType *query_point, const Size num_closest, IndexType *out_indices, DistanceType *out_distances) const
NANOFLANN_NODISCARD Size radiusSearch (const ElementType *query_point, const DistanceType &radius, std::vector< ResultItem< IndexType, DistanceType > > &IndicesDists, const SearchParameters &searchParams={}) const
template<class SEARCH_CALLBACK>
NANOFLANN_NODISCARD Size radiusSearchCustomCallback (const ElementType *query_point, SEARCH_CALLBACK &resultSet, const SearchParameters &searchParams={}) const
NANOFLANN_NODISCARD Size rknnSearch (const ElementType *query_point, const Size num_closest, IndexType *out_indices, DistanceType *out_distances, const DistanceType &radius) const
Public Member Functions inherited from nanoflann::KDTreeBaseClass< KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t >, Distance, DatasetAdaptor, -1, uint32_t >
void freeIndex (KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj)
NANOFLANN_NODISCARD Size size (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj) const noexcept
NANOFLANN_NODISCARD Size veclen (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj) const noexcept
ElementType dataset_get (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, IndexType element, Dimension component) const
 Helper accessor to the dataset points:
NANOFLANN_NODISCARD Size usedMemory (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj) const
void computeMinMax (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, Offset ind, Size count, Dimension element, ElementType &min_elem, ElementType &max_elem) const
NANOFLANN_NODISCARD bool isActive (IndexType) const
void computeBoundingBox (BoundingBox &bbox)
bool searchLevel (RESULTSET &result_set, const ElementType *vec, const NodePtr node, DistanceType mindist, distance_vector_t &dists, const DistanceType epsError) const
bool makeNode (KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, NodePtr node, const Offset left, const Offset right, BoundingBox &bbox, Offset &idx, Dimension &cutfeat, DistanceType &cutval)
void finalizeSplitNode (KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, NodePtr node, const Dimension cutfeat, const BoundingBox &left_bbox, const BoundingBox &right_bbox, BoundingBox &bbox)
NodePtr divideTree (KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, const Offset left, const Offset right, BoundingBox &bbox)
NodePtr divideTreeConcurrent (KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, const Offset left, const Offset right, BoundingBox &bbox, std::atomic< unsigned int > &thread_count, std::mutex &mutex)
void middleSplit_ (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, const Offset ind, const Size count, Offset &index, Dimension &cutfeat, DistanceType &cutval, const BoundingBox &bbox)
void planeSplit (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, const Offset ind, const Size count, const Dimension cutfeat, const DistanceType &cutval, Offset &lim1, Offset &lim2)
DistanceType computeInitialDistances (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, const ElementType *vec, distance_vector_t &dists) const
void saveIndex (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, std::ostream &stream) const
void loadIndex (KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, std::istream &stream)

Public Attributes

const DatasetAdaptor & dataset_
const KDTreeSingleIndexAdaptorParams indexParams
Distance distance_
Public Attributes inherited from nanoflann::KDTreeBaseClass< KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t >, Distance, DatasetAdaptor, -1, uint32_t >
std::vector< IndexType > vAcc_
NodePtr root_node_
Size leaf_max_size_
Size n_thread_build_
 Number of thread for concurrent tree build.
Size size_
 Number of current points in the dataset.
Size size_at_index_build_
 Number of points in the dataset when the index was built.
Dimension dim_
 Dimensionality of each data point.
BoundingBox root_bbox_
PooledAllocator pool_

Additional Inherited Members

Static Public Member Functions inherited from nanoflann::KDTreeBaseClass< KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t >, Distance, DatasetAdaptor, -1, uint32_t >
static void save_tree (const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, std::ostream &stream, const NodeConstPtr tree)
static void load_tree (KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t > &obj, std::istream &stream, NodePtr &tree)
Static Public Attributes inherited from nanoflann::KDTreeBaseClass< KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, -1, uint32_t >, Distance, DatasetAdaptor, -1, uint32_t >
static constexpr uint32_t SAVE_MAGIC

Detailed Description

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
class nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >

kd-tree static index

Contains the k-d trees and other information for indexing a set of points for nearest-neighbor matching.

The class "DatasetAdaptor" must provide the following interface (can be non-virtual, inlined methods):

// Must return the number of data points
size_t kdtree_get_point_count() const { ... }
// Must return the dim'th component of the idx'th point in the class:
T kdtree_get_pt(const size_t idx, const size_t dim) const { ... }
// Optional bounding-box computation: return false to default to a standard
bbox computation loop.
// Return true if the BBOX was already computed by the class and returned
in "bb" so it can be avoided to redo it again.
// Look at bb.size() to find out the expected dimensionality (e.g. 2 or 3
for point clouds) template <class BBOX> bool kdtree_get_bbox(BBOX &bb) const
{
bb[0].low = ...; bb[0].high = ...; // 0th dimension limits
bb[1].low = ...; bb[1].high = ...; // 1st dimension limits
...
return true;
}
Template Parameters
DatasetAdaptorThe user-provided adaptor, which must be ensured to have a lifetime equal or longer than the instance of this class.
DistanceThe distance metric to use: nanoflann::metric_L1, nanoflann::metric_L2, nanoflann::metric_L2_Simple, etc.
DIMDimensionality of data points (e.g. 3 for 3D points)
IndexTypeWill be typically size_t or int
Note
Threading guarantees:
  • Index build: passing n_thread_build > 1 in the params parallelizes the build using std::async (unless NANOFLANN_NO_THREADS is defined, in which case requesting more than one thread throws).
  • Queries (findNeighbors, knnSearch, radiusSearch, rknnSearch) are const and thread-safe for concurrent readers: multiple threads may query the same index simultaneously, as long as no thread is concurrently (re)building or modifying it.
  • The internal PooledAllocator is NOT thread-safe; building an index from multiple threads, or mixing queries with a concurrent build, is not supported.

Member Typedef Documentation

◆ Base

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
using nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::Base
Initial value:
DatasetAdaptor, DIM, index_t>
Definition nanoflann.hpp:1048
Definition nanoflann.hpp:1834

◆ BoundingBox

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
using nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::BoundingBox = typename Base::BoundingBox

Define "BoundingBox" as a fixed-size or variable-size container depending on "DIM"

◆ distance_vector_t

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
using nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::distance_vector_t = typename Base::distance_vector_t

Define "distance_vector_t" as a fixed-size or variable-size container depending on "DIM"

Constructor & Destructor Documentation

◆ KDTreeSingleIndexAdaptor() [1/2]

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::KDTreeSingleIndexAdaptor ( const KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t > & )
explicitdelete

Deleted copy constructor

◆ KDTreeSingleIndexAdaptor() [2/2]

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
template<class... Args>
nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::KDTreeSingleIndexAdaptor ( const Dimension dimensionality,
const DatasetAdaptor & inputData,
const KDTreeSingleIndexAdaptorParams & params,
Args &&... args )
inlineexplicit

KDTree constructor

Refer to docs in README.md or online in https://github.com/jlblancoc/nanoflann

The KD-Tree point dimension (the length of each point in the dataset, e.g. 3 for 3D points) is determined by means of:

  • The DIM template parameter if >0 (highest priority)
  • Otherwise, the dimensionality parameter of this constructor.
Parameters
inputDataDataset with the input features. Its lifetime must be equal or longer than that of the instance of this class.
paramsBasically, the maximum leaf node size

Note that there is a variable number of optional additional parameters which will be forwarded to the metric class constructor. Refer to example examples/pointcloud_custom_metric.cpp for a use case.

Member Function Documentation

◆ buildIndex()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
void nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::buildIndex ( )
inline

Builds the index

◆ findNeighbors()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
template<typename RESULTSET>
bool nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::findNeighbors ( RESULTSET & result,
const ElementType * vec,
const SearchParameters & searchParams = {} ) const
inline

Find set of nearest neighbors to vec[0:dim-1]. Their indices are stored inside the result object.

Params: result = the result object in which the indices of the nearest-neighbors are stored vec = the vector for which to search the nearest neighbors

Template Parameters
RESULTSETShould be any ResultSet<DistanceType>
Returns
True if the requested neighbors could be found.
See also
knnSearch, radiusSearch
Note
If L2 norms are used, all returned distances are actually squared distances.

◆ findWithinBox()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
template<typename RESULTSET>
NANOFLANN_NODISCARD Size nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::findWithinBox ( RESULTSET & result,
const BoundingBox & bbox ) const
inline

Find all points contained within the specified bounding box. Their indices are stored inside the result object.

Params: result = the result object in which the indices of the points within the bounding box are stored bbox = the bounding box defining the search region

Template Parameters
RESULTSETShould be any ResultSet<DistanceType>
Returns
Number of points found within the bounding box.
See also
findNeighbors, knnSearch, radiusSearch
Note
The search is inclusive - points on the boundary are included.

◆ init_vind()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
void nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::init_vind ( )
inline

Make sure the auxiliary list vind has the same size as the current dataset, and re-generate if size has changed.

◆ knnSearch()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
NANOFLANN_NODISCARD Size nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::knnSearch ( const ElementType * query_point,
const Size num_closest,
IndexType * out_indices,
DistanceType * out_distances ) const
inline

Find the "num_closest" nearest neighbors to the query_point[0:dim-1]. Their indices and distances are stored in the provided pointers to array/vector.

See also
radiusSearch, findNeighbors
Returns
Number N of valid points in the result set.
Note
If L2 norms are used, all returned distances are actually squared distances.
Only the first N entries in out_indices and out_distances will be valid. Return is less than num_closest only if the number of elements in the tree is less than num_closest.

◆ loadIndex()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
void nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::loadIndex ( std::istream & stream)
inline

Loads a previous index from a binary file. IMPORTANT NOTE: The set of data points is NOT stored in the file, so the index object must be constructed associated to the same source of data points used while building the index. See the example: examples/saveload_example.cpp

See also
loadIndex

◆ radiusSearch()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
NANOFLANN_NODISCARD Size nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::radiusSearch ( const ElementType * query_point,
const DistanceType & radius,
std::vector< ResultItem< IndexType, DistanceType > > & IndicesDists,
const SearchParameters & searchParams = {} ) const
inline

Find all the neighbors to query_point[0:dim-1] within a maximum radius. The output is given as a vector of pairs, of which the first element is a point index and the second the corresponding distance. Previous contents of IndicesDists are cleared.

If searchParams.sorted==true, the output list is sorted by ascending distances.

For a better performance, it is advisable to do a .reserve() on the vector if you have any wild guess about the number of expected matches.

See also
knnSearch, findNeighbors, radiusSearchCustomCallback
Returns
The number of points within the given radius (i.e. indices.size() or dists.size() )
Note
If L2 norms are used, search radius and all returned distances are actually squared distances.

◆ radiusSearchCustomCallback()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
template<class SEARCH_CALLBACK>
NANOFLANN_NODISCARD Size nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::radiusSearchCustomCallback ( const ElementType * query_point,
SEARCH_CALLBACK & resultSet,
const SearchParameters & searchParams = {} ) const
inline

Just like radiusSearch() but with a custom callback class for each point found in the radius of the query. See the source of RadiusResultSet<> as a start point for your own classes.

See also
radiusSearch

◆ rknnSearch()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
NANOFLANN_NODISCARD Size nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::rknnSearch ( const ElementType * query_point,
const Size num_closest,
IndexType * out_indices,
DistanceType * out_distances,
const DistanceType & radius ) const
inline

Find the N closest neighbors to query_point[0:dim-1] that are also within the given maximum radius. Results are stored in the provided output arrays; previous contents are overwritten.

See also
radiusSearch, findNeighbors
Returns
Number of valid points written (at most num_closest). May be less if fewer than num_closest points lie within the radius.
Note
If L2 norms are used, all returned distances are actually squared distances.
Only the first N entries in out_indices and out_distances will be valid.

◆ saveIndex()

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
void nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::saveIndex ( std::ostream & stream) const
inline

Stores the index in a binary file. IMPORTANT NOTE: The set of data points is NOT stored in the file, so when loading the index object it must be constructed associated to the same source of data points used while building it. See the example: examples/saveload_example.cpp

See also
loadIndex

Member Data Documentation

◆ dataset_

template<typename Distance, class DatasetAdaptor, int32_t DIM = -1, typename index_t = uint32_t>
const DatasetAdaptor& nanoflann::KDTreeSingleIndexAdaptor< Distance, DatasetAdaptor, DIM, index_t >::dataset_

The data source used by this index


The documentation for this class was generated from the following file: