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

Class KTjet

KTjet
hephysics.jet

Class KTjet



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

        public 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 String toString()
        Print the kT jets for debugging to a string.
        Overrides:
        toString in class 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(String[] args)
        Main class for testing.
        Parameters:
        args -

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