Recluster a jet's constituents with a new jet definition. More...

#include <fastjet/tools/Recluster.hh>

Inheritance diagram for fastjet::Recluster:

Collaboration diagram for fastjet::Recluster:

Public Types
enum	Keep { keep_only_hardest, keep_all }
	the various options for the output of Recluster More...

Public Member Functions
	Recluster ()
	default constructor (uses an undefined JetDefinition, and so cannot be used directly). More...

	Recluster (const JetDefinition &new_jet_def, bool acquire_recombiner_in=false, Keep keep_in=keep_only_hardest)
	Constructs a Recluster object that reclusters a jet into a new jet using a generic JetDefinition. More...

	Recluster (JetAlgorithm new_jet_alg, double new_jet_radius, Keep keep_in=keep_only_hardest)
	Constructs a Recluster object that reclusters a jet into a new jet using a JetAlgorithm and its parameters. More...

	Recluster (JetAlgorithm new_jet_alg, Keep keep_in=keep_only_hardest)
	constructor with just a jet algorithm, but no jet radius. More...

virtual	~Recluster ()
	default dtor

void	set_acquire_recombiner (bool acquire)
	set whether the reclustering should attempt to acquire a recombiner from the input jet

bool	acquire_recombiner () const
	returns true if this reclusterer is set to acquire the recombiner from the input jet

void	set_cambridge_optimisation (bool enabled)
	sets whether to try to optimise reclustering with Cambridge/Aachen algorithms (by not reclustering if the requested C/A reclustering can be obtained by using subjets of an input C/A jet or one composed of multiple C/A pieces from the same clustering sequence). More...

void	set_cambridge_optimization (bool enabled)
	sets whether to try to optimise reclustering with Cambridge/Aachen algorithms (US spelling!)

bool	cambridge_optimization ()
	returns true if the reclusterer tries to optimise reclustering with Cambridge/Aachen algorithms

bool	cambridge_optimisation ()

void	set_keep (Keep keep_in)
	set the behaviour with regards to keeping all resulting jets or just the hardest. More...

Keep	keep () const
	returns the current "keep" mode i.e. More...

virtual std::string	description () const
	class description

virtual PseudoJet	result (const PseudoJet &jet) const
	runs the reclustering and sets kept and rejected to be the jets of interest (with non-zero rho, they will have been subtracted). More...

bool	get_new_jets_and_def (const PseudoJet &input_jet, std::vector< PseudoJet > &output_jets) const
	A lower-level method that does the actual work of reclustering the input jet. More...

PseudoJet	generate_output_jet (std::vector< PseudoJet > &incljets, bool ca_optimisation_used) const
	given a set of inclusive jets and a jet definition used, create the resulting PseudoJet; More...

Public Member Functions inherited from fastjet::FunctionOfPseudoJet< PseudoJet >
	FunctionOfPseudoJet ()
	default ctor

virtual	~FunctionOfPseudoJet ()
	default dtor (virtual to allow safe polymorphism)

PseudoJet	operator() (const PseudoJet &pj) const
	apply the function using the "traditional" () operator. More...

std::vector< PseudoJet >	operator() (const std::vector< PseudoJet > &pjs) const
	apply the function on a vector of PseudoJet, returning a vector of the results. More...

Detailed Description

Recluster a jet's constituents with a new jet definition.

When Recluster is constructed from a JetDefinition, it is that definition that will be used to obtain the new jets. The user may then decide if the recombiner should be the one from that jet definition or if it should be acquired from the jet being processed (the default).

Alternatively, Recluster can be constructed from a jet algorithm and an optional radius. In that case the recombiner is systematically obtained from the jet being processed (unless you call set_acquire_recombiner(false)). If only the jet algorithm is specified, a default radius of max_allowable_R will be assumed if needed.

Recluster has two possible behaviours:

if it is constructed with keep=keep_only_hardest the hardest inclusive jet is returned as a "standard" jet with an associated cluster sequence (unless there were no inclusive jets, in which case a zero jet is returned, with no associated cluster sequence)
if it is constructed with keep=keep_all all the inclusive jets are joined into a composite jet

[Note that since the structure of the resulting PseudoJet depends on its usage, this class inherits from FunctionOfPseudoJet<PseudoJet> (including a description) rather than being a full-fledged Transformer]

Definition at line 73 of file Recluster.hh.

Member Enumeration Documentation

enum fastjet::Recluster::Keep

the various options for the output of Recluster

Enumerator

keep_only_hardest

keep only the hardest inclusive jet and return a "standard" jet with an associated ClusterSequence [this will be the default]

keep_all

keep all the inclusive jets.

result() will join them into a composite jet

Definition at line 76 of file Recluster.hh.

Constructor & Destructor Documentation

fastjet::Recluster::Recluster ( )

inline

default constructor (uses an undefined JetDefinition, and so cannot be used directly).

Definition at line 87 of file Recluster.hh.

fastjet::Recluster::Recluster	(	const JetDefinition &	new_jet_def,
		bool	acquire_recombiner_in = `false`,
		Keep	keep_in = `keep_only_hardest`
	)

inline

Constructs a Recluster object that reclusters a jet into a new jet using a generic JetDefinition.

Parameters

new_jet_def	the jet definition applied to do the reclustering
acquire_recombiner	when true, the reclustering will guess the recombiner from the input jet instead of the one in new_jet_def. An error is then thrown if no consistent recombiner is found
keep_in	Recluster::keep_only_hardest: the result is the hardest inclusive jet after reclustering, returned as a "standard" jet. Recluster::keep_all: the result is a composite jet with the inclusive jets as pieces.

Definition at line 104 of file Recluster.hh.

fastjet::Recluster::Recluster	(	JetAlgorithm	new_jet_alg,
		double	new_jet_radius,
		Keep	keep_in = `keep_only_hardest`
	)

Constructs a Recluster object that reclusters a jet into a new jet using a JetAlgorithm and its parameters.

Parameters

new_jet_alg	the jet algorithm applied to obtain the new clustering
new_jet_radius	the jet radius
keep_in	Recluster::keep_only_hardest: the result is the hardest inclusive jet after reclustering, returned as a "standard" jet. Recluster::keep_all: the result is a composite jet with the inclusive jets as pieces.

This ctor will always acquire the recombiner from the jet being reclustered (it will throw if none can be found). If you wish to use Recluster with an algorithm that requires an extra parameter (like the genkt algorithm), please specify the jet definition fully using the constructor above.

Definition at line 51 of file Recluster.cc.

fastjet::Recluster::Recluster	(	JetAlgorithm	new_jet_alg,
		Keep	keep_in = `keep_only_hardest`
	)

constructor with just a jet algorithm, but no jet radius.

If the algorithm requires a jet radius, JetDefinition::max_allowable_R will be used.

Definition at line 55 of file Recluster.cc.

Member Function Documentation

void fastjet::Recluster::set_cambridge_optimisation ( bool enabled )

inline

sets whether to try to optimise reclustering with Cambridge/Aachen algorithms (by not reclustering if the requested C/A reclustering can be obtained by using subjets of an input C/A jet or one composed of multiple C/A pieces from the same clustering sequence).

By default this is enabled, and should always be correct; disable it to test this statement!

Definition at line 154 of file Recluster.hh.

void fastjet::Recluster::set_keep ( Keep keep_in )

inline

set the behaviour with regards to keeping all resulting jets or just the hardest.

Definition at line 165 of file Recluster.hh.

Keep fastjet::Recluster::keep ( ) const

inline

returns the current "keep" mode i.e.

whether only the hardest inclusive jet is returned or all of them (see the Keep enum above)

Definition at line 169 of file Recluster.hh.

PseudoJet fastjet::Recluster::result ( const PseudoJet & jet ) const

virtual

runs the reclustering and sets kept and rejected to be the jets of interest (with non-zero rho, they will have been subtracted).

Normally this will be accessed through the base class's operator().

Parameters

jet	the jet that gets reclustered

Returns: the reclustered jet

Implements fastjet::FunctionOfPseudoJet< PseudoJet >.

Definition at line 87 of file Recluster.cc.

bool fastjet::Recluster::get_new_jets_and_def	(	const PseudoJet &	input_jet,
		std::vector< PseudoJet > &	output_jets
	)		const

A lower-level method that does the actual work of reclustering the input jet.

The resulting jets are stored in output_jets. The jet definition that has been used can be accessed from the output_jets' ClusterSequence.

Parameters

input_jet	the (input) jet that one wants to recluster
output_jets	inclusive jets resulting from the new clustering

Returns true if the C/A optimisation has been used (this means that generate_output_jet then has to watch out for non-explicit-ghost areas that might be leftover)

Definition at line 108 of file Recluster.cc.

PseudoJet fastjet::Recluster::generate_output_jet	(	std::vector< PseudoJet > &	incljets,
		bool	ca_optimisation_used
	)		const

given a set of inclusive jets and a jet definition used, create the resulting PseudoJet;

If ca_optimisation_used then special care will be taken in deciding whether the final jet can legitimately have an area.

Definition at line 176 of file Recluster.cc.

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

tools/fastjet/tools/Recluster.hh
tools/Recluster.cc

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation