NearestNeighborsGNAT.h
95 NearestNeighborsGNAT(unsigned int degree = 8, unsigned int minDegree = 4, unsigned int maxDegree = 12,
108 , rebuildSize_(rebalancing ? maxNumPtsPerLeaf * degree : std::numeric_limits<std::size_t>::max())
121 void setDistanceFunction(const typename NearestNeighbors<_T>::DistanceFunction &distFun) override
273 {
286 }
311 assert(i != lst.size());
399 #ifdef GNAT_SAMPLER
456 gnat.rebuildDataStructure();
508 k = i;
544 bool insertNeighborK(NearQueue &nbh, std::size_t k, const _T &data, const _T &key, double dist) const
565 void nearestK(const GNAT &gnat, const _T &data, std::size_t k, NearQueue &nbh, NodeQueue &nodeQueue,
608 distToPivot[p] + dist >= child->minRadius_))
622 void nearestR(const GNAT &gnat, const _T &data, double r, NearQueue &nbh, NodeQueue &nodeQueue) const
686 {
804 }
_T & sample(double r) const
Returns a piece of data from the PDF according to the input sampling value, which must be between 0 a...
Definition: PDF.h:196
Eigen::MatrixXd Matrix
A matrix type for storing distances between points and centers.
Definition: GreedyKCenters.h:120
Element * add(const _T &d, const double w)
Adds a piece of data with a given weight to the PDF. Returns a corresponding Element,...
Definition: PDF.h:161
void updateRange(unsigned int i, double dist)
Update minRange_[i] and maxRange_[i], given that an element was added to the i-th child of the parent...
Definition: NearestNeighborsGNAT.h:500
double maxRadius_
Maximum distance between the pivot element and the elements stored in data_.
Definition: NearestNeighborsGNAT.h:804
Geometric Near-neighbor Access Tree (GNAT), a data structure for nearest neighbor search.
Definition: NearestNeighborsGNAT.h:104
std::size_t removedCacheSize_
Maximum number of removed elements that can be stored in the removed_ cache. If the cache is full,...
Definition: NearestNeighborsGNAT.h:853
std::size_t rebuildSize_
If size_ exceeds rebuildSize_, the tree will be rebuilt (and automatically rebalanced),...
Definition: NearestNeighborsGNAT.h:849
unsigned int minDegree_
After splitting a Node, each child Node has degree equal to the default degree times the fraction of ...
Definition: NearestNeighborsGNAT.h:836
void rebuildDataStructure()
Rebuild the internal data structure.
Definition: NearestNeighborsGNAT.h:242
std::vector< _T > data_
The data elements stored in this node (in addition to the pivot element). An internal node has no ele...
Definition: NearestNeighborsGNAT.h:813
void nearestK(const _T &data, std::size_t k, std::vector< _T > &nbh) const override
Return the k nearest neighbors in sorted order.
Definition: NearestNeighborsGNAT.h:286
void nearestK(const GNAT &gnat, const _T &data, std::size_t k, NearQueue &nbh, NodeQueue &nodeQueue, bool &isPivot) const
Compute the k nearest neighbors of data in the tree. For k=1, isPivot is true if the nearest neighbor...
Definition: NearestNeighborsGNAT.h:629
void nearestR(const _T &data, double radius, std::vector< _T > &nbh) const override
Return the nearest neighbors within distance radius in sorted order.
Definition: NearestNeighborsGNAT.h:300
Node(int degree, int capacity, _T pivot)
Construct a node of given degree with at most capacity data elements and with given pivot.
Definition: NearestNeighborsGNAT.h:456
bool reportsSortedResults() const override
Return true if the solutions reported by this data structure are sorted, when calling nearestK / near...
Definition: NearestNeighborsGNAT.h:206
double minRadius_
Minimum distance between the pivot element and the elements stored in data_.
Definition: NearestNeighborsGNAT.h:802
std::function< double(const _T &, const _T &)> DistanceFunction
The definition of a distance function.
Definition: NearestNeighbors.h:115
Node * tree_
The data structure containing the elements stored in this structure.
Definition: NearestNeighborsGNAT.h:829
unsigned int maxDegree_
After splitting a Node, each child Node has degree equal to the default degree times the fraction of ...
Definition: NearestNeighborsGNAT.h:841
bool needToSplit(const GNAT &gnat) const
Return true iff the node needs to be split into child nodes.
Definition: NearestNeighborsGNAT.h:549
GreedyKCenters< _T > pivotSelector_
The data structure used to split data into subtrees.
Definition: NearestNeighborsGNAT.h:855
void add(const _T &data) override
Add an element to the datastructure.
Definition: NearestNeighborsGNAT.h:211
bool isRemoved(const _T &data) const
Return true iff data has been marked for removal.
Definition: NearestNeighborsGNAT.h:390
std::vector< double > minRange_
The i-th element in minRange_ is the minimum distance between the pivot and any data_ element in the ...
Definition: NearestNeighborsGNAT.h:807
Abstract representation of a container that can perform nearest neighbors queries.
Definition: NearestNeighbors.h:79
void split(GNAT &gnat)
The split operation finds pivot elements for the child nodes and moves each data element of this node...
Definition: NearestNeighborsGNAT.h:557
std::vector< double > maxRange_
The i-th element in maxRange_ is the maximum distance between the pivot and any data_ element in the ...
Definition: NearestNeighborsGNAT.h:810
std::size_t size() const override
Get the number of elements in the datastructure.
Definition: NearestNeighborsGNAT.h:311
std::vector< Node * > children_
The child nodes of this node. By definition, only internal nodes have child nodes.
Definition: NearestNeighborsGNAT.h:816
void nearestR(const GNAT &gnat, const _T &data, double r, NearQueue &nbh, NodeQueue &nodeQueue) const
Return all elements that are within distance r in nbh. The nodeQueue, which contains other Nodes that...
Definition: NearestNeighborsGNAT.h:686
void setDistanceFunction(const typename NearestNeighbors< _T >::DistanceFunction &distFun) override
Set the distance function to use.
Definition: NearestNeighborsGNAT.h:185
void insertNeighborR(NearQueue &nbh, double r, const _T &data, double dist) const
Insert data in nbh if it is a near neighbor.
Definition: NearestNeighborsGNAT.h:678
void updateRadius(double dist)
Update minRadius_ and maxRadius_, given that an element was added with distance dist to the pivot.
Definition: NearestNeighborsGNAT.h:480
void list(std::vector< _T > &data) const override
Get all the elements in the datastructure.
Definition: NearestNeighborsGNAT.h:327
void add(GNAT &gnat, const _T &data)
Add an element to the tree rooted at this node.
Definition: NearestNeighborsGNAT.h:508
bool remove(const _T &data) override
Remove data from the tree. The element won't actually be removed immediately, but just marked for rem...
Definition: NearestNeighborsGNAT.h:254
std::unordered_set< const _T * > removed_
Cache of removed elements.
Definition: NearestNeighborsGNAT.h:857
void postprocessNearest(NearQueue &nbhQueue, std::vector< _T > &nbh) const
Convert the internal data structure used for storing neighbors to the vector that NearestNeighbor API...
Definition: NearestNeighborsGNAT.h:443
unsigned int maxNumPtsPerLeaf_
Maximum number of elements allowed to be stored in a Node before it needs to be split into several no...
Definition: NearestNeighborsGNAT.h:844
friend std::ostream & operator<<(std::ostream &out, const NearestNeighborsGNAT< _T > &gnat)
Print a GNAT structure (mostly useful for debugging purposes).
Definition: NearestNeighborsGNAT.h:336
bool nearestKInternal(const _T &data, std::size_t k, NearQueue &nbhQueue) const
Return in nbhQueue the k nearest neighbors of data. For k=1, return true if the nearest neighbor is a...
Definition: NearestNeighborsGNAT.h:399
void nearestRInternal(const _T &data, double radius, NearQueue &nbhQueue) const
Return in nbhQueue the elements that are within distance radius of data.
Definition: NearestNeighborsGNAT.h:422
_T nearest(const _T &data) const override
Get the nearest neighbor of a point.
Definition: NearestNeighborsGNAT.h:273
The class used internally to define the GNAT.
Definition: NearestNeighborsGNAT.h:451
virtual void setDistanceFunction(const DistanceFunction &distFun)
Set the distance function to use.
Definition: NearestNeighbors.h:122
bool insertNeighborK(NearQueue &nbh, std::size_t k, const _T &data, const _T &key, double dist) const
Insert data in nbh if it is a near neighbor. Return true iff data was added to nbh.
Definition: NearestNeighborsGNAT.h:608