fastjet::DnnPlane Class Reference

class derived from DynamicNearestNeighbours that provides an implementation for the Euclidean plane More...

#include <DnnPlane.hh>

Inheritance diagram for fastjet::DnnPlane:

[legend]Collaboration diagram for fastjet::DnnPlane:


Public Member Functions
	DnnPlane ()
	empty initaliser
	DnnPlane (const std::vector< EtaPhi > &, const bool &verbose=false)
	Initialiser from a set of points on an Eta-Phi plane, where both eta and phi can have arbitrary ranges.
int	NearestNeighbourIndex (const int &ii) const
	Returns the index of the nearest neighbour of point labelled by ii (assumes ii is valid).
double	NearestNeighbourDistance (const int &ii) const
	Returns the distance to the nearest neighbour of point labelled by index ii (assumes ii is valid).
bool	Valid (const int &index) const
	Returns true iff the given index corresponds to a point that exists in the DNN structure (meaning that it has been added, and not removed in the meantime).
void	RemoveAndAddPoints (const std::vector< int > &indices_to_remove, const std::vector< EtaPhi > &points_to_add, std::vector< int > &indices_added, std::vector< int > &indices_of_updated_neighbours)
	remove the points labelled by the std::vector indices_to_remove, and add the points specified by the std::vector points_to_add (corresponding indices will be calculated automatically); the idea behind this routine is that the points to be added will somehow be close to the one or other of the points being removed and this can be used by the implementation to provide hints for inserting the new points in whatever structure it is using.
EtaPhi	etaphi (const int i) const
	returns the EtaPhi of point with index i.
double	eta (const int i) const
	returns the eta point with index i.
double	phi (const int i) const
	returns the phi point with index i.
Private Member Functions
double	_euclid_distance (const Point &p1, const Point &p2) const
	calculates and returns the euclidean distance between points p1 and p2
void	_SetNearest (const int &j)
	Determines the index and distance of the nearest neighbour to point j and puts the information into the _supervertex entry for j.
void	_SetAndUpdateNearest (const int &j, std::vector< int > &indices_of_updated_neighbours)
	Determines and stores the nearest neighbour of j.
void	_CrashIfVertexPresent (const Vertex_handle &vertex, const int &its_index)
	Crashes if the given vertex handle already exists.
Private Attributes
std::vector< SuperVertex >	_supervertex
bool	_verbose
Triangulation	_TR
Static Private Attributes
static const bool	_crash_on_coincidence = true
Classes
struct	SuperVertex
	Structure containing a vertex_handle and cached information on the nearest neighbour. More...

Detailed Description

class derived from DynamicNearestNeighbours that provides an implementation for the Euclidean plane

Definition at line 45 of file DnnPlane.hh.

Constructor & Destructor Documentation

fastjet::DnnPlane::DnnPlane ( ) [inline]

empty initaliser

Definition at line 48 of file DnnPlane.hh.

00048 {}

fastjet::DnnPlane::DnnPlane	(	const std::vector< EtaPhi > &	,
		const bool &	verbose = `false`
	)

Initialiser from a set of points on an Eta-Phi plane, where both eta and phi can have arbitrary ranges.

Member Function Documentation

int fastjet::DnnPlane::NearestNeighbourIndex ( const int & ii ) const [inline, virtual]

Returns the index of the nearest neighbour of point labelled by ii (assumes ii is valid).

Implements fastjet::DynamicNearestNeighbours.

Definition at line 138 of file DnnPlane.hh.

References _supervertex.

Referenced by fastjet::Dnn4piCylinder::NearestNeighbourIndex(), fastjet::Dnn3piCylinder::NearestNeighbourIndex(), and fastjet::Dnn2piCylinder::NearestNeighbourIndex().

00138                                                                {
00139   return _supervertex[ii].NNindex;}

double fastjet::DnnPlane::NearestNeighbourDistance ( const int & ii ) const [inline, virtual]

Returns the distance to the nearest neighbour of point labelled by index ii (assumes ii is valid).

Implements fastjet::DynamicNearestNeighbours.

Definition at line 141 of file DnnPlane.hh.

References _supervertex.

Referenced by fastjet::Dnn4piCylinder::NearestNeighbourDistance(), fastjet::Dnn3piCylinder::NearestNeighbourDistance(), fastjet::Dnn2piCylinder::NearestNeighbourDistance(), fastjet::Dnn4piCylinder::NearestNeighbourIndex(), fastjet::Dnn3piCylinder::NearestNeighbourIndex(), and fastjet::Dnn2piCylinder::NearestNeighbourIndex().

00141                                                                      {
00142   return _supervertex[ii].NNdistance;}

bool fastjet::DnnPlane::Valid ( const int & index ) const [inline, virtual]

Returns true iff the given index corresponds to a point that exists in the DNN structure (meaning that it has been added, and not removed in the meantime).

Implements fastjet::DynamicNearestNeighbours.

Definition at line 144 of file DnnPlane.hh.

References _supervertex.

Referenced by fastjet::Dnn4piCylinder::Valid(), fastjet::Dnn3piCylinder::Valid(), and fastjet::Dnn2piCylinder::Valid().

00144                                                    {
00145   if (index >= 0 && index < static_cast<int>(_supervertex.size())) {
00146     return (_supervertex[index].vertex != NULL);} else {return false;} }

void fastjet::DnnPlane::RemoveAndAddPoints	(	const std::vector< int > &	indices_to_remove,
		const std::vector< EtaPhi > &	points_to_add,
		std::vector< int > &	indices_added,
		std::vector< int > &	indices_of_updated_neighbours
	)			`[virtual]`

remove the points labelled by the std::vector indices_to_remove, and add the points specified by the std::vector points_to_add (corresponding indices will be calculated automatically); the idea behind this routine is that the points to be added will somehow be close to the one or other of the points being removed and this can be used by the implementation to provide hints for inserting the new points in whatever structure it is using.

In a kt-algorithm the points being added will be a result of a combination of the points to be removed -- hence the proximity is (more or less) guaranteed.

Implements fastjet::DynamicNearestNeighbours.

EtaPhi fastjet::DnnPlane::etaphi ( const int i ) const [inline]

returns the EtaPhi of point with index i.

Definition at line 148 of file DnnPlane.hh.

References _supervertex, fastjet::Point::x, and fastjet::Point::y.

00148                                                 {
00149   Point * p = & (_supervertex[i].vertex->point());
00150   return EtaPhi(p->x(),p->y()); }

double fastjet::DnnPlane::eta ( const int i ) const [inline]

returns the eta point with index i.

Definition at line 152 of file DnnPlane.hh.

References _supervertex.

00152                                              {
00153   return _supervertex[i].vertex->point().x(); }

double fastjet::DnnPlane::phi ( const int i ) const [inline]

returns the phi point with index i.

Definition at line 155 of file DnnPlane.hh.

References _supervertex.

00155                                              {
00156   return _supervertex[i].vertex->point().y(); }

double fastjet::DnnPlane::_euclid_distance	(	const Point &	p1,
		const Point &	p2
	)			const `[inline, private]`

calculates and returns the euclidean distance between points p1 and p2

Definition at line 102 of file DnnPlane.hh.

References fastjet::Point::x, and fastjet::Point::y.

Referenced by _SetNearest().

00102                                                                          {
00103     double distx= p1.x()-p2.x();
00104     double disty= p1.y()-p2.y();
00105     return distx*distx+disty*disty;
00106   }

void fastjet::DnnPlane::_SetNearest ( const int & j ) [private]

Determines the index and distance of the nearest neighbour to point j and puts the information into the _supervertex entry for j.

Definition at line 261 of file DnnPlane.cc.

References _euclid_distance(), _supervertex, _TR, _verbose, fastjet::HUGE_DOUBLE, and fastjet::INFINITE_VERTEX.

00261                                          {
00262   Vertex_handle current = _supervertex[j].vertex;
00263   Vertex_circulator vc = _TR.incident_vertices(current);
00264   Vertex_circulator done = vc;
00265   double dist;
00266   double mindist = HUGE_DOUBLE; // change this to "HUGE" or max_double?
00267   Vertex_handle nearest = _TR.infinite_vertex();
00268 
00269   // when there is only one finite point left in the triangulation, 
00270   // there are no triangles. Presumably this is why voronoi returns
00271   // NULL for the incident vertex circulator. Check if this is
00272   // happening before circulating over it... (Otherwise it crashes
00273   // when looking for neighbours of last point)
00274   if (vc != NULL) do { 
00275     if ( vc->info().val() != INFINITE_VERTEX) {
00276       // find distance between j and its Voronoi neighbour (vc)
00277       if (_verbose) cout << current->info().val() << " " << vc->info().val() << endl;
00278       dist = _euclid_distance(current->point(), vc->point());
00279       // check if j is closer to vc than vc's currently registered
00280       // nearest neighbour (and update things if it is)
00281       if (dist < mindist) {
00282         mindist = dist; nearest = vc; 
00283         if (_verbose) cout << "nearer ";
00284       } 
00285       if (_verbose) cout << vc->point() << "; "<< dist << endl;
00286     }
00287   } while (++vc != done); // move on to next Voronoi neighbour
00288   // set j's supervertex info about nearest neighbour
00289   _supervertex[j].NNindex = nearest->info().val();
00290   _supervertex[j].NNdistance = mindist;
00291 }

void fastjet::DnnPlane::_SetAndUpdateNearest	(	const int &	j,
		std::vector< int > &	indices_of_updated_neighbours
	)			`[private]`

Determines and stores the nearest neighbour of j.

For each voronoi neighbour D of j if the distance between j and D is less than D's own nearest neighbour, then update the nearest-neighbour info in D; push D's index onto indices_of_updated_neighbours

Note that j is NOT pushed onto indices_of_updated_neighbours -- if you want it there, put it there yourself.

void fastjet::DnnPlane::_CrashIfVertexPresent	(	const Vertex_handle &	vertex,
		const int &	its_index
	)			`[private]`

Crashes if the given vertex handle already exists.

Otherwise it does the bookkeeping for future such tests

Definition at line 80 of file DnnPlane.cc.

References _crash_on_coincidence, and fastjet::NEW_VERTEX.

00081                                                              {
00082   if (!_crash_on_coincidence) return;
00083 
00084   // vertices that do not have the same geometric position as any
00085   // other vertex so far added have info().val() == NEW_VERTEX -- this
00086   // is ensured by the InitialisedInt class, which forms the "info"
00087   // part of our
00088   // CGAL::Triangulation_vertex_base_with_info_2<InitialisedInt,K>
00089   //
00090   // If the vertex coincides with one that already exists, then
00091   // info().val() it's info().val() will have been updated (in
00092   // DNN:DNN) to be equal to a vertex "index".
00093   if (vertex->info().val() != NEW_VERTEX) {
00094     ostringstream err;
00095     err << "ERROR in DnnPlane::_CrashIfVertexPresent"
00096          <<endl << "Point "<<its_index<<" coincides with point "
00097          <<vertex->info().val() << endl;
00098     throw DnnError(err.str());
00099   } 
00100 }