CosmicMuon.h

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/******************************************************************************
 *   Copyright (C) 2019 GSI Helmholtzzentrum für Schwerionenforschung GmbH    *
 *   Copyright (C) 2019-2024 Members of R3B Collaboration                     *
 *                                                                            *
 *             This software is distributed under the terms of the            *
 *                 GNU General Public Licence (GPL) version 3,                *
 *                    copied verbatim in the file "LICENSE".                  *
 *                                                                            *
 * In applying this license GSI does not waive the privileges and immunities  *
 * granted to it by virtue of its status as an Intergovernmental Organization *
 * or submit itself to any jurisdiction.                                      *
 ******************************************************************************/
 
#pragma once
#include "FairPrimaryGenerator.h"
#include "RtypesCore.h"
#include "TRandom.h"
#include <FairGenerator.h>
#include <Math/GenVector/Cartesian3D.h>
#include <Math/GenVector/Polar3D.h>
#include <Math/GenVector/PxPyPzE4D.h>
#include <R3BIOConnector.h>
#include <R3BNeulandCommon.h>
#include <Rtypes.h>
#include <TMath.h>
#include <TRandom3.h>
#include <memory>
#include <utility>
 
namespace R3B::Neuland
{
    struct AngleInfo
    {
        double sin_phi{};
        double sin_theta{};
        double cos_phi{};
        double cos_theta{};
    };
 
    struct MuonTrackInfo
    {
        ROOT::Math::PxPyPzE4D<double> momentum;
        ROOT::Math::Cartesian3D<double> position;
 
        ClassDefNV(MuonTrackInfo, 1);
    };
 
    constexpr auto default_detector_size{ 200.0 };
    constexpr auto default_PID{ 13 };
 
    class TrackGeneratorAbstract
    {
      public:
        TrackGeneratorAbstract() = default;
        TrackGeneratorAbstract(const TrackGeneratorAbstract&) = default;
        TrackGeneratorAbstract(TrackGeneratorAbstract&&) = default;
        auto operator=(const TrackGeneratorAbstract&) -> TrackGeneratorAbstract& = default;
        auto operator=(TrackGeneratorAbstract&&) -> TrackGeneratorAbstract& = default;
        virtual ~TrackGeneratorAbstract() = default;
 
        virtual void set_detector_size(double detector_size) = 0;
        virtual auto ReadEvent(FairPrimaryGenerator* prim_gen) -> bool = 0;
        virtual void set_rd_engine(TRandom* user_rd_engine) = 0;
        virtual void set_PID(int PID) = 0;
    };
 
    template <typename AngleDist, typename EnergyDist, typename PositionDist>
    class TrackGeneratorImp : public TrackGeneratorAbstract
    {
      public:
        TrackGeneratorImp(const AngleDist& angle_dist, const EnergyDist& energy_dist, const PositionDist& position_dist)
            : angle_dist_{ angle_dist }
            , energy_dist_{ energy_dist }
            , position_dist_{ position_dist }
        {
            muon_track_output_.init();
        }
 
        void set_detector_size(double detector_size) override { detector_size_ = detector_size; }
        void set_rd_engine(TRandom* user_rd_engine) override { rd_engine_ = user_rd_engine; }
        void set_PID(int PID) override { PID_ = PID; }
 
      private:
        using MomentumPosition = std::pair<ROOT::Math::PxPyPzE4D<double>, ROOT::Math::Cartesian3D<double>>;
        using Momentum = ROOT::Math::PxPyPzE4D<double>;
        using AngleRadius = ROOT::Math::Polar3D<double>;
        double detector_size_{ default_detector_size };
        int PID_{ default_PID };
 
        R3B::OutputVectorConnector<MuonTrackInfo> muon_track_output_{ "muon_track_info" };
        AngleDist angle_dist_{};
        EnergyDist energy_dist_{};
        PositionDist position_dist_{};
        TRandom* rd_engine_{ gRandom };
 
        // Paula: which methods have to be virtual?
        auto rd_num_gen_angles(const AngleDist& angle_dist) -> AngleRadius;
        auto calculate_momentum_energy(const double& kinetic_energy, const AngleInfo& angle_info) -> Momentum;
 
        auto calculate_external_position_momentum(const AngleDist& angle_dist,
                                                  const EnergyDist& energy_dist,
                                                  const PositionDist& position_dist) -> MomentumPosition;
        auto ReadEvent(FairPrimaryGenerator* prim_gen) -> bool override
        {
            muon_track_output_.clear();
            auto& muon_track = muon_track_output_.get().emplace_back();
            auto momentum_position =
                MomentumPosition{ calculate_external_position_momentum(angle_dist_, energy_dist_, position_dist_) };
            muon_track.momentum = momentum_position.first;
            muon_track.position = momentum_position.second;
            prim_gen->AddTrack(PID_,
                               momentum_position.first.Px(),
                               momentum_position.first.Py(),
                               momentum_position.first.Pz(),
                               momentum_position.second.X(),
                               momentum_position.second.Y(),
                               momentum_position.second.Z());
            return true;
        };
    };
 
    template <typename AngleDist, typename EnergyDist, typename PositionDist>
    auto TrackGeneratorImp<AngleDist, EnergyDist, PositionDist>::rd_num_gen_angles(const AngleDist& angle_dist)
        -> AngleRadius
    {
        auto angles = AngleRadius{};
        angles.SetPhi(rd_engine_->Uniform(0., 2 * TMath::Pi()));
        // angles.SetTheta(0);
        angles.SetTheta(angle_dist(rd_engine_));
 
        return angles;
    }
 
    template <typename AngleDist, typename EnergyDist, typename PositionDist>
    auto TrackGeneratorImp<AngleDist, EnergyDist, PositionDist>::calculate_momentum_energy(const double& kinetic_energy,
                                                                                           const AngleInfo& angle_info)
        -> Momentum
    {
        auto total_energy = kinetic_energy + MUON_MASS;
        auto momentum_energy = Momentum{ 0, 0, 0, total_energy };
        momentum_energy.SetPx(kinetic_energy * angle_info.sin_theta * angle_info.cos_phi);
        momentum_energy.SetPy(kinetic_energy * angle_info.cos_theta);
        momentum_energy.SetPz(kinetic_energy * angle_info.sin_theta * angle_info.sin_phi);
        return momentum_energy;
    }
 
    template <typename AngleDist, typename EnergyDist, typename PositionDist>
    auto TrackGeneratorImp<AngleDist, EnergyDist, PositionDist>::calculate_external_position_momentum(
        const AngleDist& angle_dist,
        const EnergyDist& energy_dist,
        const PositionDist& position_dist) -> MomentumPosition
    {
        auto const position = position_dist(rd_engine_);
        // //cout looking for errors
        // std::cout << "x Posistion: "<< position.X()<<"\n";
        // std::cout << "y Posistion: "<< position.Y()<<"\n";
        // std::cout << "z Posistion: "<< position.Z()<<"\n";
        auto const angles = rd_num_gen_angles(angle_dist);
        auto const energy = energy_dist(rd_engine_);
 
        auto angle_info = AngleInfo{};
        angle_info.sin_phi = std::sin(angles.Phi());
        angle_info.cos_phi = std::cos(angles.Phi());
        angle_info.sin_theta = std::sin(angles.Theta());
        angle_info.cos_theta = std::cos(angles.Theta());
 
        auto position_momentum = MomentumPosition{};
 
        position_momentum.second.SetX(position.X() - angle_info.sin_theta * angle_info.cos_phi * detector_size_);
        position_momentum.second.SetY(position.Y() - angle_info.cos_theta * detector_size_);
        position_momentum.second.SetZ(position.Z() - angle_info.sin_theta * angle_info.sin_phi * detector_size_);
        position_momentum.first = calculate_momentum_energy(energy, angle_info);
 
        return position_momentum;
    }
 
    class TrackGenerator : public FairGenerator
    {
      public:
        TrackGenerator();
        template <typename AngleDist, typename EnergyDist, typename PositionDist>
        TrackGenerator(AngleDist angle_dist, EnergyDist energy_dist, PositionDist position_dist)
            : ptr_{ std::make_unique<TrackGeneratorImp<AngleDist, EnergyDist, PositionDist>>(angle_dist,
                                                                                             energy_dist,
                                                                                             position_dist) }
        {
        }
        void set_detector_size(double detector_size) { ptr_->set_detector_size(detector_size); }
        void set_rd_engine(TRandom* user_rd_engine) { ptr_->set_rd_engine(user_rd_engine); }
        void set_PID(int PID) { ptr_->set_PID(PID); }
 
        auto get_ptr() -> TrackGeneratorAbstract* { return ptr_.get(); }
 
      private:
        std::unique_ptr<TrackGeneratorAbstract> ptr_; 
        auto ReadEvent(FairPrimaryGenerator* prim_gen) -> Bool_t override
        {
            ptr_->ReadEvent(prim_gen);
            return true;
        }
 
        ClassDefOverride(TrackGenerator, 1); // NOLINT
    };
 
    template <typename AngleDist, typename EnergyDist, typename PositionDist>
    auto CreateTrackGenerator(const AngleDist& angle_dist,
                              const EnergyDist& energy_dist,
                              const PositionDist& position_dist)
    {
        return std::make_unique<TrackGenerator>(angle_dist, energy_dist, position_dist);
    }
} // namespace R3B::Neuland