ProtonReconstruction/interface/ProtonReconstructionAlgorithm.h

0001 /****************************************************************************
0002  * Authors:
0003  *   Jan Kašpar
0004  *   Laurent Forthomme
0005  ****************************************************************************/
0006
0007 #ifndef RecoPPS_ProtonReconstruction_ProtonReconstructionAlgorithm_h
0008 #define RecoPPS_ProtonReconstruction_ProtonReconstructionAlgorithm_h
0009
0010 #include "FWCore/ParameterSet/interface/ParameterSet.h"
0011
0012 #include "DataFormats/CTPPSReco/interface/CTPPSLocalTrackLiteFwd.h"
0013 #include "DataFormats/ProtonReco/interface/ForwardProtonFwd.h"
0014
0015 #include "CondFormats/PPSObjects/interface/LHCInterpolatedOpticalFunctionsSet.h"
0016 #include "CondFormats/PPSObjects/interface/LHCInterpolatedOpticalFunctionsSetCollection.h"
0017
0018 #include "TSpline.h"
0019 #include "Fit/Fitter.h"
0020
0021 #include <unordered_map>
0022
0023 //----------------------------------------------------------------------------------------------------
0024
0025 class ProtonReconstructionAlgorithm {
0026 public:
0027   ProtonReconstructionAlgorithm(bool fit_vtx_y,
0028                                 bool improved_estimate,
0029                                 const std::string &multiRPAlgorithm,
0030                                 unsigned int verbosity);
0031   ~ProtonReconstructionAlgorithm() = default;
0032
0033   void init(const LHCInterpolatedOpticalFunctionsSetCollection &opticalFunctions);
0034   void release();
0035
0036   /// run proton reconstruction using single-RP strategy
0037   reco::ForwardProton reconstructFromSingleRP(const CTPPSLocalTrackLiteRef &track,
0038                                               const float energy,
0039                                               std::ostream &os) const;
0040
0041   /// run proton reconstruction using multiple-RP strategy
0042   reco::ForwardProton reconstructFromMultiRP(const CTPPSLocalTrackLiteRefVector &tracks,
0043                                              const float energy,
0044                                              std::ostream &os) const;
0045
0046 private:
0047   unsigned int verbosity_;
0048   bool fitVtxY_;
0049   bool useImprovedInitialEstimate_;
0050   enum { mrpaUndefined, mrpaChi2, mrpaNewton, mrpaAnalIter } multi_rp_algorithm_;
0051   bool initialized_;
0052
0053   /// optics data associated with 1 RP
0054   struct RPOpticsData {
0055     const LHCInterpolatedOpticalFunctionsSet *optics;
0056     std::shared_ptr<const TSpline3> s_x_d_vs_xi, s_L_x_vs_xi, s_xi_vs_x_d, s_y_d_vs_xi, s_v_y_vs_xi, s_L_y_vs_xi;
0057     double x0;   ///< beam horizontal position, cm
0058     double y0;   ///< beam vertical position, cm
0059     double ch0;  ///< intercept for linear approximation of \f$x(\xi)\f$
0060     double ch1;  ///< slope for linear approximation of \f$x(\xi)\f$
0061     double la0;  ///< intercept for linear approximation of \f$L_x(\xi)\f$
0062     double la1;  ///< slope for linear approximation of \f$L_x(\xi)\f$
0063   };
0064
0065   /// map: RP id --> optics data
0066   std::map<unsigned int, RPOpticsData> m_rp_optics_;
0067
0068   /// class for calculation of chi^2
0069   class ChiSquareCalculator {
0070   public:
0071     ChiSquareCalculator() = default;
0072
0073     double operator()(const double *parameters) const;
0074
0075     const CTPPSLocalTrackLiteRefVector *tracks;
0076     const std::map<unsigned int, RPOpticsData> *m_rp_optics;
0077   };
0078
0079   /// fitter object
0080   std::unique_ptr<ROOT::Fit::Fitter> fitter_;
0081
0082   /// object to calculate chi^2
0083   std::unique_ptr<ChiSquareCalculator> chiSquareCalculator_;
0084
0085   static void doLinearFit(const std::vector<double> &vx, const std::vector<double> &vy, double &b, double &a);
0086
0087   static double newtonGoalFcn(double xi, double x_N, double x_F, const RPOpticsData &i_N, const RPOpticsData &i_F);
0088 };
0089
0090 #endif