fastjet::JadePlugin Class Reference

JadePlugin is a plugin for fastjet (v2.4 upwards). More...

#include <JadePlugin.hh>

Inheritance diagram for fastjet::JadePlugin:

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Collaboration diagram for fastjet::JadePlugin:

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List of all members.

Public Member Functions
	JadePlugin ()
	Main constructor for the Jade Plugin class.
	JadePlugin (const JadePlugin &plugin)
	copy constructor
virtual std::string	description () const
	return a textual description of the jet-definition implemented in this plugin
virtual void	run_clustering (ClusterSequence &) const
	given a ClusterSequence that has been filled up with initial particles, the following function should fill up the rest of the ClusterSequence, using the following member functions of ClusterSequence: plugin_do_ij_recombination(.
virtual double	R () const
	the plugin mechanism's standard way of accessing the jet radius.
virtual bool	exclusive_sequence_meaningful () const
	avoid the warning whenever the user requests "exclusive" jets from the cluster sequence

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Detailed Description

JadePlugin is a plugin for fastjet (v2.4 upwards).

It implements the JADE algorithm, which is an e+e- sequential recombination algorithm with interparticle distance

dij = 2 E_i E_j (1 - cos theta_ij)

or equivalently

yij = dij/E_{vis}^2

This corresponds to the distance measured used in

"Experimental Investigation of the Energy Dependence of the Strong Coupling Strength." JADE Collaboration (S. Bethke et al.) Phys.Lett.B213:235,1988

The JADE article carries out particle recombinations in the E-scheme (4-vector recombination), which is the default procedure for this plugin.

NOTE: other widely used schemes include E0, P, P0; however they also involve modifications to the distance measure. Be sure of what you're doing before running a JADE type algorithm.

To access the jets with a given ycut value (clustering stops once all yij > ycut), use

vector<PseudoJet> jets = cluster_sequence.exclusive_jets_ycut(ycut);

and related routines.

Definition at line 75 of file JadePlugin.hh.

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Constructor & Destructor Documentation

fastjet::JadePlugin::JadePlugin

(

)

[inline]

Main constructor for the Jade Plugin class.

Definition at line 78 of file JadePlugin.hh.

{}

fastjet::JadePlugin::JadePlugin

(

const JadePlugin &

plugin

)

[inline]

copy constructor

Definition at line 81 of file JadePlugin.hh.

                                         {
    *this = plugin;
  }

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Member Function Documentation

string fastjet::JadePlugin::description

(

)

const [virtual]

return a textual description of the jet-definition implemented in this plugin

Implements JetDefinition::Plugin.

Definition at line 81 of file JadePlugin.cc.

                                      {
  ostringstream desc;
  desc << "e+e- JADE algorithm plugin";
  return desc.str();
}

virtual bool fastjet::JadePlugin::exclusive_sequence_meaningful

(

)

const [inline, virtual]

avoid the warning whenever the user requests "exclusive" jets from the cluster sequence

Reimplemented from JetDefinition::Plugin.

Definition at line 96 of file JadePlugin.hh.

{return true;}

virtual double fastjet::JadePlugin::R

(

)

const [inline, virtual]

the plugin mechanism's standard way of accessing the jet radius.

This must be set to return something sensible, even if R does not make sense for this algorithm!

Implements JetDefinition::Plugin.

Definition at line 92 of file JadePlugin.hh.

{return 1.0;}

void fastjet::JadePlugin::run_clustering

(

ClusterSequence &

)

const [virtual]

given a ClusterSequence that has been filled up with initial particles, the following function should fill up the rest of the ClusterSequence, using the following member functions of ClusterSequence:

• plugin_do_ij_recombination(.

..)

• plugin_do_iB_recombination(...)

Implements JetDefinition::Plugin.

Definition at line 88 of file JadePlugin.cc.

References ClusterSequence::jets(), ClusterSequence::plugin_record_iB_recombination(), and ClusterSequence::plugin_record_ij_recombination().

                                                          {
  int njets = cs.jets().size();
  NNH<JadeBriefJet> nnh(cs.jets());

  // if testing against Hoeth's implementation, need to rescale the
  // dij by Q^2.
  //double Q2 = cs.Q2(); 

  while (njets > 0) {
    int i, j, k;
    double dij = nnh.dij_min(i, j);

    if (j >= 0) {
      cs.plugin_record_ij_recombination(i, j, dij, k);
      nnh.merge_jets(i, j, cs.jets()[k], k);
    } else {
      double diB = cs.jets()[i].E()*cs.jets()[i].E(); // get new diB
      cs.plugin_record_iB_recombination(i, diB);
      nnh.remove_jet(i);
    }
    njets--;
  }
}

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

• plugins/Jade/fastjet/JadePlugin.hh
• plugins/Jade/JadePlugin.cc