Help solve closest pair problems with generic interparticle and beam distance (generic case) More...

#include <fastjet/NNH.hh>

Inheritance diagram for fastjet::NNH< BJ, I >:

Collaboration diagram for fastjet::NNH< BJ, I >:

Public Member Functions
	NNH (const std::vector< PseudoJet > &jets)
	constructor with an initial set of jets (which will be assigned indices 0 ... More...

	NNH (const std::vector< PseudoJet > &jets, I *info)

void	start (const std::vector< PseudoJet > &jets)
	initialisation from a given list of particles

double	dij_min (int &iA, int &iB)
	return the dij_min and indices iA, iB, for the corresponding jets. More...

void	remove_jet (int iA)
	remove the jet pointed to by index iA

void	merge_jets (int iA, int iB, const PseudoJet &jet, int jet_index)
	merge the jets pointed to by indices A and B and replace them with jet, assigning it an index jet_index. More...

	~NNH ()
	a destructor

Public Member Functions inherited from fastjet::NNBase< I >
	NNBase ()
	Default constructor.

	NNBase (I *info)
	Constuctor with additional Info.

Public Member Functions inherited from fastjet::NNInfo< I >
	NNInfo (I *info)

template<class BJ >
void	init_jet (BJ *briefjet, const fastjet::PseudoJet &jet, int index)

Detailed Description

template<class BJ, class I = _NoInfo>
class fastjet::NNH< BJ, I >

Help solve closest pair problems with generic interparticle and beam distance (generic case)

(see NNBase.hh for an introductory description)

This variant provides an implementation for any distance measure. It is templated with a BJ (brief jet) classand can be used with or without an extra "Information" template, i.e. NNH<BJ> or NNH<BJ,I>

For the NNH<BJ> version of the class to function, BJ must provide three member functions

void BJ::init(const PseudoJet & jet); // initialise with a PseudoJet
double BJ::distance(const BJ * other_bj_jet); // distance between this and other_bj_jet
double BJ::beam_distance() ; // distance to the beam

For the NNH<BJ,I> version to function, the BJ::init(...) member must accept an extra argument

void BJ::init(const PseudoJet & jet, I * info); // initialise with a PseudoJet + info

NOTE: THE DISTANCE MUST BE SYMMETRIC I.E. SATISFY a.distance(b) == b.distance(a)

For an example of how the NNH<BJ> class is used, see the Jade (and EECambridge) plugins

NB: the NNH algorithm is expected N^2, but has a worst case of N^3. Many QCD problems tend to place one closer to the N^3 end of the spectrum than one would like. There is scope for further progress (cf Eppstein, Cardinal & Eppstein), nevertheless the current class is already significantly faster than standard N^3 implementations.

Definition at line 75 of file NNH.hh.

Constructor & Destructor Documentation

◆ NNH()

template<class BJ, class I = _NoInfo>

fastjet::NNH< BJ, I >::NNH ( const std::vector< PseudoJet > & jets )

inline

constructor with an initial set of jets (which will be assigned indices 0 ...

jets.size()-1

Definition at line 80 of file NNH.hh.

Member Function Documentation

◆ dij_min()

template<class BJ , class I >

double fastjet::NNH< BJ, I >::dij_min	(	int &	iA,
		int &	iB
	)

virtual

return the dij_min and indices iA, iB, for the corresponding jets.

If iB < 0 then iA recombines with the beam

Implements fastjet::NNBase< I >.

Definition at line 187 of file NNH.hh.

◆ merge_jets()

template<class BJ , class I >

void fastjet::NNH< BJ, I >::merge_jets	(	int	iA,
		int	iB,
		const PseudoJet &	jet,
		int	jet_index
	)

virtual

merge the jets pointed to by indices A and B and replace them with jet, assigning it an index jet_index.

Implements fastjet::NNBase< I >.

Definition at line 230 of file NNH.hh.

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

include/fastjet/NNH.hh

Public Member Functions