Detailed Description

A generic adaptor class for providing Approximate Nearest Neighbors (ANN) (via the nanoflann library) to MRPT classses.

This makes use of the CRTP design pattern.

Derived classes must be aware of the need to call "kdtree_mark_as_outdated()" when the data points change to mark the cached KD-tree (an "index") as invalid, and also implement the following interface (note that these are not virtual functions due to the usage of CRTP):

   // Must return the number of data points
   inline size_t kdtree_get_point_count() const { ... }

   // Returns the distance between the vector "p1[0:size-1]" and the data point with index "idx_p2" stored in the class:
   inline float kdtree_distance(const float *p1, const size_t idx_p2,size_t size) const { ... }

   // Returns the dim'th component of the idx'th point in the class:
   inline num_t kdtree_get_pt(const size_t idx, int 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 = ...;  // "x" limits
      return true;
   }

The KD-tree index will be built on demand only upon call of any of the query methods provided by this class.

Notice that there is only ONE internal cached KD-tree, so if a method to query a 2D point is called, then another method for 3D points, then again the 2D method, three KD-trees will be built. So, try to group all the calls for a given dimensionality together or build different class instances for queries of each dimensionality, etc.

See also:: See some of the derived classes for example implementations. See also the documentation of nanoflann

#include <mrpt/math/KDTreeCapable.h>

Inheritance diagram for mrpt::math::KDTreeCapable:

[legend]

List of all members.

Classes
struct	TKDTreeDataHolder
	Internal structure with the KD-tree representation (mainly used to avoid copying pointers with the = operator) More...
struct	TKDTreeSearchParams
Public Types
typedef KDTreeCapable< Derived, num_t, metric_t >	self_t
Public Member Functions
	KDTreeCapable ()
	Constructor.
	~KDTreeCapable ()
	Destructor (nothing needed to do here)
const Derived &	derived () const
	CRTP helper method.
Derived &	derived ()
	CRTP helper method.
Public utility methods to query the KD-tree
size_t	kdTreeClosestPoint2D (float x0, float y0, float &out_x, float &out_y, float &out_dist_sqr) const
	KD Tree-based search for the closest point (only ONE) to some given 2D coordinates.
size_t	kdTreeClosestPoint2D (float x0, float y0, float &out_dist_sqr) const
size_t	kdTreeClosestPoint2D (const TPoint2D &p0, TPoint2D &pOut, float &outDistSqr) const
float	kdTreeClosestPoint2DsqrError (float x0, float y0) const
	Like kdTreeClosestPoint2D, but just return the square error from some point to its closest neighbor.
float	kdTreeClosestPoint2DsqrError (const TPoint2D &p0) const
void	kdTreeTwoClosestPoint2D (float x0, float y0, float &out_x1, float &out_y1, float &out_x2, float &out_y2, float &out_dist_sqr1, float &out_dist_sqr2) const
	KD Tree-based search for the TWO closest point to some given 2D coordinates.
void	kdTreeTwoClosestPoint2D (const TPoint2D &p0, TPoint2D &pOut1, TPoint2D &pOut2, float &outDistSqr1, float &outDistSqr2) const
std::vector< int >	kdTreeNClosestPoint2D (float x0, float y0, size_t knn, std::vector< float > &out_x, std::vector< float > &out_y, std::vector< float > &out_dist_sqr) const
	KD Tree-based search for the N closest point to some given 2D coordinates.
std::vector< int >	kdTreeNClosestPoint2D (const TPoint2D &p0, size_t N, std::vector< TPoint2D > &pOut, std::vector< float > &outDistSqr) const
void	kdTreeNClosestPoint2DIdx (float x0, float y0, size_t knn, std::vector< int > &out_idx, std::vector< float > &out_dist_sqr) const
	KD Tree-based search for the N closest point to some given 2D coordinates and returns their indexes.
void	kdTreeNClosestPoint2DIdx (const TPoint2D &p0, size_t N, std::vector< int > &outIdx, std::vector< float > &outDistSqr) const
size_t	kdTreeClosestPoint3D (float x0, float y0, float z0, float &out_x, float &out_y, float &out_z, float &out_dist_sqr) const
	KD Tree-based search for the closest point (only ONE) to some given 3D coordinates.
size_t	kdTreeClosestPoint3D (float x0, float y0, float z0, float &out_dist_sqr) const
size_t	kdTreeClosestPoint3D (const TPoint3D &p0, TPoint3D &pOut, float &outDistSqr) const
void	kdTreeNClosestPoint3D (float x0, float y0, float z0, size_t knn, std::vector< float > &out_x, std::vector< float > &out_y, std::vector< float > &out_z, std::vector< float > &out_dist_sqr) const
	KD Tree-based search for the N closest points to some given 3D coordinates.
void	kdTreeNClosestPoint3D (const TPoint3D &p0, size_t N, std::vector< TPoint3D > &pOut, std::vector< float > &outDistSqr) const
void	kdTreeNClosestPoint3DIdx (float x0, float y0, float z0, size_t knn, std::vector< int > &out_idx, std::vector< float > &out_dist_sqr) const
	KD Tree-based search for the N closest point to some given 3D coordinates and returns their indexes.
void	kdTreeNClosestPoint3DIdx (const TPoint3D &p0, size_t N, std::vector< int > &outIdx, std::vector< float > &outDistSqr) const
Public Attributes
TKDTreeSearchParams	kdtree_search_params
	Parameters to tune the ANN searches.
Protected Member Functions
void	kdtree_mark_as_outdated () const
	To be called by child classes when KD tree data changes.
Private Member Functions
void	rebuild_kdTree_2D () const
	Rebuild, if needed the KD-tree for 2D (nDims=2), 3D (nDims=3), ... asking the child class for the data points.
void	rebuild_kdTree_3D () const
	Rebuild, if needed the KD-tree for 2D (nDims=2), 3D (nDims=3), ... asking the child class for the data points.
void	rebuild_kdTree_Nd (const size_t nDims) const
	Rebuild, if needed the KD-tree for 2D (nDims=2), 3D (nDims=3), ... asking the child class for the data points.
Private Attributes
TKDTreeDataHolder< 2 >	m_kdtree2d_data
TKDTreeDataHolder< 3 >	m_kdtree3d_data
TKDTreeDataHolder	m_kdtreeNd_data
bool	m_kdtree_is_uptodate
	whether the KD tree needs to be rebuilt or not.

Member Typedef Documentation

typedef KDTreeCapable<Derived,num_t,metric_t> mrpt::math::KDTreeCapable::self_t

Definition at line 90 of file KDTreeCapable.h.

Constructor & Destructor Documentation

mrpt::math::KDTreeCapable::KDTreeCapable ( ) [inline]

Constructor.

Definition at line 94 of file KDTreeCapable.h.

mrpt::math::KDTreeCapable::~KDTreeCapable ( ) [inline]

Destructor (nothing needed to do here)

Definition at line 97 of file KDTreeCapable.h.

Member Function Documentation

const Derived& mrpt::math::KDTreeCapable::derived ( ) const [inline]

CRTP helper method.

Definition at line 100 of file KDTreeCapable.h.

Derived& mrpt::math::KDTreeCapable::derived ( ) [inline]

CRTP helper method.

Definition at line 102 of file KDTreeCapable.h.

void mrpt::math::KDTreeCapable::kdtree_mark_as_outdated ( ) const [inline, protected]

To be called by child classes when KD tree data changes.

Definition at line 575 of file KDTreeCapable.h.

size_t mrpt::math::KDTreeCapable::kdTreeClosestPoint2D	(	float	x0,
		float	y0,
		float &	out_x,
		float &	out_y,
		float &	out_dist_sqr
	)		const `[inline]`

KD Tree-based search for the closest point (only ONE) to some given 2D coordinates.

This method automatically build the "m_kdtree_data" structure when:

It is called for the first time
The map has changed
The KD-tree was build for 3D.

Parameters:

x0	The X coordinate of the query.
y0	The Y coordinate of the query.
out_x	The X coordinate of the found closest correspondence.
out_y	The Y coordinate of the found closest correspondence.
out_dist_sqr	The square distance between the query and the returned point.

Returns:: The index of the closest point in the map array.

See also:: kdTreeClosestPoint3D, kdTreeTwoClosestPoint2D

Definition at line 136 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeClosestPoint2D(), and mrpt::math::KDTreeCapable< CFeatureList >::kdTreeClosestPoint2DsqrError().

size_t mrpt::math::KDTreeCapable::kdTreeClosestPoint2D	(	float	x0,
		float	y0,
		float &	out_dist_sqr
	)		const `[inline]`

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 166 of file KDTreeCapable.h.

size_t mrpt::math::KDTreeCapable::kdTreeClosestPoint2D	(	const TPoint2D &	p0,
		TPoint2D &	pOut,
		float &	outDistSqr
	)		const `[inline]`

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 189 of file KDTreeCapable.h.

float mrpt::math::KDTreeCapable::kdTreeClosestPoint2DsqrError	(	float	x0,
		float	y0
	)		const `[inline]`

Like kdTreeClosestPoint2D, but just return the square error from some point to its closest neighbor.

Definition at line 199 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeClosestPoint2DsqrError().

float mrpt::math::KDTreeCapable::kdTreeClosestPoint2DsqrError ( const TPoint2D & p0 ) const [inline]

Definition at line 208 of file KDTreeCapable.h.

size_t mrpt::math::KDTreeCapable::kdTreeClosestPoint3D	(	float	x0,
		float	y0,
		float	z0,
		float &	out_x,
		float &	out_y,
		float &	out_z,
		float &	out_dist_sqr
	)		const `[inline]`

KD Tree-based search for the closest point (only ONE) to some given 3D coordinates.

This method automatically build the "m_kdtree_data" structure when:

It is called for the first time
The map has changed
The KD-tree was build for 2D.

Parameters:

x0	The X coordinate of the query.
y0	The Y coordinate of the query.
z0	The Z coordinate of the query.
out_x	The X coordinate of the found closest correspondence.
out_y	The Y coordinate of the found closest correspondence.
out_z	The Z coordinate of the found closest correspondence.
out_dist_sqr	The square distance between the query and the returned point.

Returns:: The index of the closest point in the map array.

See also:: kdTreeClosestPoint2D

Definition at line 394 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeClosestPoint3D().

size_t mrpt::math::KDTreeCapable::kdTreeClosestPoint3D	(	float	x0,
		float	y0,
		float	z0,
		float &	out_dist_sqr
	)		const `[inline]`

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 428 of file KDTreeCapable.h.

size_t mrpt::math::KDTreeCapable::kdTreeClosestPoint3D	(	const TPoint3D &	p0,
		TPoint3D &	pOut,
		float &	outDistSqr
	)		const `[inline]`

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 454 of file KDTreeCapable.h.

std::vector<int> mrpt::math::KDTreeCapable::kdTreeNClosestPoint2D	(	float	x0,
		float	y0,
		size_t	knn,
		std::vector< float > &	out_x,
		std::vector< float > &	out_y,
		std::vector< float > &	out_dist_sqr
	)		const `[inline]`

KD Tree-based search for the N closest point to some given 2D coordinates.

This method automatically build the "m_kdtree_data" structure when:

It is called for the first time
The map has changed
The KD-tree was build for 3D.

Parameters:

x0	The X coordinate of the query.
y0	The Y coordinate of the query.
N	The number of closest points to search.
out_x	The vector containing the X coordinates of the correspondences.
out_y	The vector containing the Y coordinates of the correspondences.
out_dist_sqr	The vector containing the square distance between the query and the returned points.

Returns:: The list of indices

See also:: kdTreeClosestPoint2D; kdTreeTwoClosestPoint2D

Definition at line 293 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeNClosestPoint2D().

std::vector<int> mrpt::math::KDTreeCapable::kdTreeNClosestPoint2D	(	const TPoint2D &	p0,
		size_t	N,
		std::vector< TPoint2D > &	pOut,
		std::vector< float > &	outDistSqr
	)		const `[inline]`

Definition at line 326 of file KDTreeCapable.h.

void mrpt::math::KDTreeCapable::kdTreeNClosestPoint2DIdx	(	float	x0,
		float	y0,
		size_t	knn,
		std::vector< int > &	out_idx,
		std::vector< float > &	out_dist_sqr
	)		const `[inline]`

KD Tree-based search for the N closest point to some given 2D coordinates and returns their indexes.

This method automatically build the "m_kdtree_data" structure when:

It is called for the first time
The map has changed
The KD-tree was build for 3D.

Parameters:

x0	The X coordinate of the query.
y0	The Y coordinate of the query.
N	The number of closest points to search.
out_idx	The indexes of the found closest correspondence.
out_dist_sqr	The square distance between the query and the returned point.

See also:: kdTreeClosestPoint2D

Definition at line 351 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeNClosestPoint2DIdx().

void mrpt::math::KDTreeCapable::kdTreeNClosestPoint2DIdx	(	const TPoint2D &	p0,
		size_t	N,
		std::vector< int > &	outIdx,
		std::vector< float > &	outDistSqr
	)		const `[inline]`

Definition at line 373 of file KDTreeCapable.h.

void mrpt::math::KDTreeCapable::kdTreeNClosestPoint3D	(	float	x0,
		float	y0,
		float	z0,
		size_t	knn,
		std::vector< float > &	out_x,
		std::vector< float > &	out_y,
		std::vector< float > &	out_z,
		std::vector< float > &	out_dist_sqr
	)		const `[inline]`

KD Tree-based search for the N closest points to some given 3D coordinates.

This method automatically build the "m_kdtree_data" structure when:

It is called for the first time
The map has changed
The KD-tree was build for 2D.

Parameters:

x0	The X coordinate of the query.
y0	The Y coordinate of the query.
z0	The Z coordinate of the query.
N	The number of closest points to search.
out_x	The vector containing the X coordinates of the correspondences.
out_y	The vector containing the Y coordinates of the correspondences.
out_z	The vector containing the Z coordinates of the correspondences.
out_dist_sqr	The vector containing the square distance between the query and the returned points.

See also:: kdTreeNClosestPoint2D

Definition at line 480 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeNClosestPoint3D().

void mrpt::math::KDTreeCapable::kdTreeNClosestPoint3D	(	const TPoint3D &	p0,
		size_t	N,
		std::vector< TPoint3D > &	pOut,
		std::vector< float > &	outDistSqr
	)		const `[inline]`

Definition at line 517 of file KDTreeCapable.h.

void mrpt::math::KDTreeCapable::kdTreeNClosestPoint3DIdx	(	float	x0,
		float	y0,
		float	z0,
		size_t	knn,
		std::vector< int > &	out_idx,
		std::vector< float > &	out_dist_sqr
	)		const `[inline]`

KD Tree-based search for the N closest point to some given 3D coordinates and returns their indexes.

This method automatically build the "m_kdtree_data" structure when:

It is called for the first time
The map has changed
The KD-tree was build for 2D.

Parameters:

x0	The X coordinate of the query.
y0	The Y coordinate of the query.
z0	The Z coordinate of the query.
N	The number of closest points to search.
out_idx	The indexes of the found closest correspondence.
out_dist_sqr	The square distance between the query and the returned point.

See also:: kdTreeClosestPoint2D

Definition at line 543 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeNClosestPoint3DIdx().

void mrpt::math::KDTreeCapable::kdTreeNClosestPoint3DIdx	(	const TPoint3D &	p0,
		size_t	N,
		std::vector< int > &	outIdx,
		std::vector< float > &	outDistSqr
	)		const `[inline]`

Definition at line 567 of file KDTreeCapable.h.

void mrpt::math::KDTreeCapable::kdTreeTwoClosestPoint2D	(	float	x0,
		float	y0,
		float &	out_x1,
		float &	out_y1,
		float &	out_x2,
		float &	out_y2,
		float &	out_dist_sqr1,
		float &	out_dist_sqr2
	)		const `[inline]`

KD Tree-based search for the TWO closest point to some given 2D coordinates.

This method automatically build the "m_kdtree_data" structure when:

It is called for the first time
The map has changed
The KD-tree was build for 3D.

Parameters:

x0	The X coordinate of the query.
y0	The Y coordinate of the query.
out_x1	The X coordinate of the first correspondence.
out_y1	The Y coordinate of the first correspondence.
out_x2	The X coordinate of the second correspondence.
out_y2	The Y coordinate of the second correspondence.
out_dist_sqr1	The square distance between the query and the first returned point.
out_dist_sqr2	The square distance between the query and the second returned point.

See also:: kdTreeClosestPoint2D

Definition at line 229 of file KDTreeCapable.h.

Referenced by mrpt::math::KDTreeCapable< CFeatureList >::kdTreeTwoClosestPoint2D().

void mrpt::math::KDTreeCapable::kdTreeTwoClosestPoint2D	(	const TPoint2D &	p0,
		TPoint2D &	pOut1,
		TPoint2D &	pOut2,
		float &	outDistSqr1,
		float &	outDistSqr2
	)		const `[inline]`