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Practical implementation of the algorithm

KtJet uses the HepLorentzVector class of the CLHEP package [7]. The input 4-vectors (the objects on which the algorithm will be run) may be HepLorentzVectors or KtLorentzVectors. The KtLorentzVector class, which inherits from HepLorentzVector, carries an internal index which allows the user to determine, for example, to which final state jet a particular input particle belongs. Examples of the use of KtLorentzVector are given in section 3.2. The output 4-vectors (the jets) are instantiated as KtLorentzVectors. The KtLorentzVector class has the constructors

KtLorentzVector(const HepLorentzVector &);
KtLorentzVector(const KtLorentzVector &);
KtLorentzVector(float Px, float Py, float Pz, float E);

The first step in running the algorithm is the creation of a KtEvent object. There are separate constructors to run the algorithm in inclusive and exclusive modes respectively:

KtEvent(const std::vector<KtLorentzVector> particles &, int type, int angle, int recom, float rparameter);

KtEvent(const std::vector<KtLorentzVector> particles &, int type, int angle, int recom);

There are also versions of these constructors taking vectors of HepLorentzVectors instead of KtLorentzVectors. The parameter type should be set to the colliding beam type, as defined in table 1. The parameters angle and recom are described in sections 2.4 and 2.5. rparameter is the parameter $R$ defined in section 2.1 and should almost always be set to $1.0$, although values smaller than $1.0$ have been suggested for certain applications [5,6].

Table 1: Possible input values for type.

type	Beam	Comments
1	$ee$
2	$ep$	$p$ in $-z$ direction
3	$pe$	$p$ in $+z$ direction
4	$pp$