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/RunInfo/interface/LHCInfo.h"
0016 #include "CondFormats/PPSObjects/interface/LHCInterpolatedOpticalFunctionsSet.h"
0017 #include "CondFormats/PPSObjects/interface/LHCInterpolatedOpticalFunctionsSetCollection.h"
0018
0019 #include "TSpline.h"
0020 #include "Fit/Fitter.h"
0021
0022 #include <unordered_map>
0023
0024 //----------------------------------------------------------------------------------------------------
0025
0026 class ProtonReconstructionAlgorithm {
0027 public:
0028   ProtonReconstructionAlgorithm(bool fit_vtx_y,
0029                                 bool improved_estimate,
0030                                 const std::string &multiRPAlgorithm,
0031                                 unsigned int verbosity);
0032   ~ProtonReconstructionAlgorithm() = default;
0033
0034   void init(const LHCInterpolatedOpticalFunctionsSetCollection &opticalFunctions);
0035   void release();
0036
0037   /// run proton reconstruction using single-RP strategy
0038   reco::ForwardProton reconstructFromSingleRP(const CTPPSLocalTrackLiteRef &track,
0039                                               const LHCInfo &lhcInfo,
0040                                               std::ostream &os) const;
0041
0042   /// run proton reconstruction using multiple-RP strategy
0043   reco::ForwardProton reconstructFromMultiRP(const CTPPSLocalTrackLiteRefVector &tracks,
0044                                              const LHCInfo &lhcInfo,
0045                                              std::ostream &os) const;
0046
0047 private:
0048   unsigned int verbosity_;
0049   bool fitVtxY_;
0050   bool useImprovedInitialEstimate_;
0051   enum { mrpaUndefined, mrpaChi2, mrpaNewton, mrpaAnalIter } multi_rp_algorithm_;
0052   bool initialized_;
0053
0054   /// optics data associated with 1 RP
0055   struct RPOpticsData {
0056     const LHCInterpolatedOpticalFunctionsSet *optics;
0057     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;
0058     double x0;   ///< beam horizontal position, cm
0059     double y0;   ///< beam vertical position, cm
0060     double ch0;  ///< intercept for linear approximation of \f$x(\xi)\f$
0061     double ch1;  ///< slope for linear approximation of \f$x(\xi)\f$
0062     double la0;  ///< intercept for linear approximation of \f$L_x(\xi)\f$
0063     double la1;  ///< slope for linear approximation of \f$L_x(\xi)\f$
0064   };
0065
0066   /// map: RP id --> optics data
0067   std::map<unsigned int, RPOpticsData> m_rp_optics_;
0068
0069   /// class for calculation of chi^2
0070   class ChiSquareCalculator {
0071   public:
0072     ChiSquareCalculator() = default;
0073
0074     double operator()(const double *parameters) const;
0075
0076     const CTPPSLocalTrackLiteRefVector *tracks;
0077     const std::map<unsigned int, RPOpticsData> *m_rp_optics;
0078   };
0079
0080   /// fitter object
0081   std::unique_ptr<ROOT::Fit::Fitter> fitter_;
0082
0083   /// object to calculate chi^2
0084   std::unique_ptr<ChiSquareCalculator> chiSquareCalculator_;
0085
0086   static void doLinearFit(const std::vector<double> &vx, const std::vector<double> &vy, double &b, double &a);
0087
0088   static double newtonGoalFcn(double xi, double x_N, double x_F, const RPOpticsData &i_N, const RPOpticsData &i_F);
0089 };
0090
0091 #endif