API documentation of the 'hephysics.jet.KTjet' Java class
KTjet
hephysics.jet

Class KTjet

KTjet
hephysics.jet

Class KTjet



  • public class KTjetextends java.lang.Object
    Longitudinally-invariant kT, anti-KT and Cambridge/Aachen clustering algorithms (light-weight implementation). This class uses float values for fast computation and ParticleF with float definitions. The algorithm uses phi-pseudorapidity to define distances, similar to the Tevatron approach.

    To speed-up calculations and to have a low memory footprint, it uses ParticleF with float definitions. Use slower SCJet class for with double types and rapidity, similar to the LHC approach. This class uses E-scheme to combine particles (p1+p2). More details in http://arxiv.org/pdf/hep-ph/0210022v1.pdf.
    • Constructor Summary

      Constructors 
      Constructor and Description
      KTjet(double R, double minpt)
      Initialize calculations of the KT algorithm.
      KTjet(double R, int recom, double minpt)
      Initialize calculations of the KT algorithm.
      KTjet(double R, int recom, int mode, double minpt)
      Initialize calculations of the longitudinally invariant kT algorithm in inclusive mode.
    • Constructor Detail

      • KTjet

        public KTjet(double R,             int recom,             int mode,             double minpt)
        Initialize calculations of the longitudinally invariant kT algorithm in inclusive mode. Jet can be clustered using Cambridge/Aachen or anti-kT approaches, depending on the "mode" parameter. The distance parameters are Eta (pseudorapidity) and Phi.
        Parameters:
        R - distance measure
        recom - recombination scheme.
        1: The E-scheme Simple 4-vector addition.
        2: The pT-scheme.
        3: The pT^2 scheme.
        Currently only E-scheme is implemented.
        mode - clustering mode dij=min(kT_i^{2* mode},kT_j^{2* mode})).
        mode=1 means inclusive KT jet algorithm
        mode=0 means Cambridge/Aachen jet algorithm
        mode=-1 means anti-KT jet algorithm
        minpt - min pT for final jets.
      • KTjet

        public KTjet(double R,             int recom,             double minpt)
        Initialize calculations of the KT algorithm. Meaningful values are R=0.2- 1. Jets are clustered in Eta (pseudorapidity) and Phi space.
        Parameters:
        R - distance measure
        recom - recombination scheme.
        1: The E-scheme Simple 4-vector addition.
        2: The pT-scheme.
        3: The pT^2 scheme.
        Currently only E-scheme is implemented.
        minpt - min pT for final jets.
      • KTjet

        public KTjet(double R,             double minpt)
        Initialize calculations of the KT algorithm. Meaningful values are R=0.2- 1. Jets are clustered in Eta (pseudorapidity) and Phi space. The The E-scheme with 4-vector addition is used.
        Parameters:
        R - distance measure
        minpt - min pT for final jets.
    • Method Detail

      • buildJets

        public java.util.ArrayList<ParticleF> buildJets(java.util.ArrayList<ParticleF> list)
        Run the jet algorithm using the list of particles
        Parameters:
        list - list with particles
        Returns:
        final jets without sorting.
      • getJetsSorted

        public java.util.ArrayList<ParticleF> getJetsSorted()
        Get jets after sorting in jet pT. Run buildJets before calling this method.
        Returns:
        list with sorted jets
      • printJets

        public void printJets()
        Print the kT jets for debugging.
      • toString

        public java.lang.String toString()
        Print the kT jets for debugging to a string.
        Overrides:
        toString in class java.lang.Object
        Returns:
        String representing a jet
      • getKtDistance12

        public float getKtDistance12(ParticleF a,                             ParticleF b)
        Calculate delta R distance.
        Parameters:
        a - input particle
        b - input particle
        p - power parameter
        Returns:
        Kt distance
      • getDistance

        public float getDistance(ParticleF a,                         ParticleF b)
        Calculate R distance in eta-phi.
        Parameters:
        a - input particle
        b - input particle
        Returns:
        eta-phi distance
      • getKtDistance1

        public float getKtDistance1(ParticleF a)
        This is the KT distance to the beam (assuming Z=Y=0). The distance measure depends on the mode parameter.
        Parameters:
        a - particle
        Returns:
        kT distance
      • setDebug

        public void setDebug(boolean debug)
        Print debugging information. It shows how much time spend to make jets in ms.
        Parameters:
        debug - true if printing benchmark information.
      • main

        public static void main(java.lang.String[] args)
        Main class for testing.
        Parameters:
        args -

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