fastjet::Subtractor Class Reference

Class that helps performing jet background subtraction. More...

#include <Subtractor.hh>

Inheritance diagram for fastjet::Subtractor:

Collaboration diagram for fastjet::Subtractor:

List of all members.

Public Member Functions
	Subtractor (BackgroundEstimator *bge)
	define a subtractor based on a BackgroundEstimator
virtual	~Subtractor ()
	default dtor
virtual PseudoJet	result (const PseudoJet &jet) const
	returns a jet that's subtracted
virtual std::string	description () const
	class description
Protected Attributes
BackgroundEstimator *	_bge
	the tool used to estimate the background if has to be mutable in case its underlying selector takes a reference jet

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Detailed Description

Class that helps performing jet background subtraction.

This class is nothing but a transformer that makes use of the BackgroundEstimator introduced above to subtract the background from the jet.

Options

The constructor takes as an argument a BackgroundEstimator.

Input conditions

• the original jet must have area support (4-vector)

Output/structure

The structure of the jet is not modified.

Definition at line 61 of file Subtractor.hh.

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Member Function Documentation

PseudoJet fastjet::Subtractor::result

(

const PseudoJet &

jet

)

const [virtual]

returns a jet that's subtracted

Parameters:

jet	the jet that is to be subtracted

Returns:

the subtracted jet

Implements fastjet::Transformer.

Definition at line 35 of file Subtractor.cc.

References fastjet::PseudoJet::area_4vector(), fastjet::PseudoJet::has_area(), and fastjet::PseudoJet::perp().

                                                        {
  if (!jet.has_area()){
    throw Error("Trying to subtract a jet without area support");
  }
  
  double rho = _bge->rho(jet);
  PseudoJet subtracted_jet = jet;
  PseudoJet area4vect = jet.area_4vector();
  // sanity check
  if (rho*area4vect.perp() < jet.perp() ) { 
    // this subtraction should retain the jet's structural
    // information
    subtracted_jet -= rho*area4vect;
  } else { 
    // this sets the jet's momentum to zero while
    // maintaining all of the jet's structural information
    subtracted_jet *= 0;
  }
  return subtracted_jet;
}

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

• tools/fastjet/tools/Subtractor.hh
• tools/Subtractor.cc