Vector_Resolution.h

Go to the documentation of this file.

//
//
// File: hitfit/Vector_Resolution.h
// Purpose: Calculate resolutions in p, phi, eta.
// Created: Jul, 2000, sss, based on run 1 mass analysis code.
//
// These objects hold three Resolution objects, one each for p, phi, eta.
// In addition, we have a use_et flag; if set, then the p resolution
// is really in pt.
//
// We can initialize these objects from a string; the format is
//
//   <p-res>/<eta-res>/<phi-res>[/et]
//
// where the resolution formats are as given in Resolution.h.
//
// CMSSW File      : interface/Vector_Resolution.h
// Original Author : Scott Stuart Snyder <snyder@bnl.gov> for D0
// Imported to CMSSW by Haryo Sumowidagdo <Suharyo.Sumowidagdo@cern.ch>
//

#ifndef HITFIT_VECTOR_RESOLUTION_H
#define HITFIT_VECTOR_RESOLUTION_H

#include <string>
#include <iosfwd>
#include "TopQuarkAnalysis/TopHitFit/interface/Resolution.h"
#include "TopQuarkAnalysis/TopHitFit/interface/fourvec.h"

namespace hitfit {

  class Vector_Resolution
  //
  // Purpose: Calculate resolutions in p, phi, eta.
  //
  {
  public:
    // Constructor.  Create a vector resolution object with infinite precision
    Vector_Resolution();

    // Constructor.  Parse a string as described above.
    Vector_Resolution(std::string s);

    // Constructor from individual resolution objects.
    Vector_Resolution(const Resolution& p_res,
                      const Resolution& eta_res,
                      const Resolution& phi_res,
                      bool use_et = false);

    // Get back the individual resolution objects.
    const Resolution& p_res() const;

    const Resolution& eta_res() const;

    const Resolution& phi_res() const;

    // Return the use_et flag.
    bool use_et() const;

    // Calculate resolutions from a 4-momentum.
    double p_sigma(const Fourvec& v) const;

    double eta_sigma(const Fourvec& v) const;

    double phi_sigma(const Fourvec& v) const;

    // Smear a 4-vector V according to the resolutions.
    // If DO_SMEAR_DIR is false, only smear the total energy.
    void smear(Fourvec& v, CLHEP::HepRandomEngine& engine, bool do_smear_dir = false) const;

    // Dump this object, for debugging.
    friend std::ostream& operator<<(std::ostream& s, const Vector_Resolution& r);

  private:
    // State for this object.
    Resolution _p_res;

    Resolution _eta_res;

    Resolution _phi_res;

    bool _use_et;

    // Helper.
    void smear_dir(Fourvec& v, CLHEP::HepRandomEngine& engine) const;
  };

}  // namespace hitfit

#endif  // not HITFIT_VECTOR_RESOLUTION_H