src/JERC/JetResolutionObject.h

#ifndef JetResolutionObject_h
#define JetResolutionObject_h

// If you want to use the JER code in standalone mode, you'll need to create a new define named 'STANDALONE'. If you use gcc for compiling, you'll need to add
// -DSTANDALONE to the command line
// In standalone mode, no reference to CMSSW exists, so the only way to retrieve resolutions and scale factors are from text files.
#define STANDALONE

#ifndef STANDALONE
#include "CondFormats/Serialization/interface/Serializable.h"
#else
// Create no-op definitions of CMSSW macro
#define COND_SERIALIZABLE
#define COND_TRANSIENT
#endif

#include <unordered_map>
#include <vector>
#include <string>
#include <tuple>
#include <memory>
#include <initializer_list>

#ifndef STANDALONE
#include "CommonTools/Utils/interface/FormulaEvaluator.h"
#else
#include <TFormula.h>
#endif

enum class Variation {
    NOMINAL = 0,
    DOWN = 1,
    UP = 2
};

template <typename T>
T clip(const T& n, const T& lower, const T& upper) {
    return std::max(lower, std::min(n, upper));
}

namespace JME {
    template <typename T, typename U>
    struct bimap {
        typedef std::unordered_map<T, U> left_type;
        typedef std::unordered_map<U, T> right_type;

        left_type left;
        right_type right;
        
        bimap(std::initializer_list<typename left_type::value_type> l) {
            for (auto& v: l) {
                left.insert(v);
                right.insert(typename right_type::value_type(v.second, v.first));
            }
        }

        bimap() {
            // Empty
        }

        bimap(bimap&& rhs) {
            left = std::move(rhs.left);
            right = std::move(rhs.right);
        }
    };

    enum class Binning {
        JetPt = 0,
        JetEta,
        JetAbsEta,
        JetE,
        JetArea,
        Mu,
        Rho,
        NPV,
    };

}

// Hash function for Binning enum class
namespace std {
    template<>
    struct hash<JME::Binning> {
        typedef JME::Binning argument_type;
        typedef std::size_t result_type;

        hash<uint8_t> int_hash;
 
        result_type operator()(argument_type const& s) const {
            return int_hash(static_cast<uint8_t>(s));
        }
    };
}

namespace JME {

    class JetParameters {
        public:
            typedef std::unordered_map<Binning, float> value_type;

            JetParameters() = default;
            JetParameters(JetParameters&& rhs);
            JetParameters(std::initializer_list<typename value_type::value_type> init);


            JetParameters& setJetPt(float pt);
            JetParameters& setJetEta(float eta);
            JetParameters& setJetE(float e);
            JetParameters& setJetArea(float area);
            JetParameters& setMu(float mu);
            JetParameters& setRho(float rho);
            JetParameters& setNPV(float npv);
            JetParameters& set(const Binning& bin, float value);
            JetParameters& set(const typename value_type::value_type& value);

            static const bimap<Binning, std::string> binning_to_string;

            std::vector<float> createVector(const std::vector<Binning>& binning) const;

        private:
            value_type m_values;
    };


    class JetResolutionObject {

        public:

            struct Range {
                float min;
                float max;

                Range() {
                    // Empty
                }

                Range(float min, float max) {
                    this->min = min;
                    this->max = max;
                }

                bool is_inside(float value) const {
                    return (value >= min) && (value <= max);
                }

                COND_SERIALIZABLE;
            };

            class Definition {

                public:
                    Definition() {
                        // Empty
                    }

                    Definition(const std::string& definition);

                    const std::vector<std::string>& getBinsName() const {
                        return m_bins_name;
                    }

                    const std::vector<Binning>& getBins() const {
                        return m_bins;
                    }

                    std::string getBinName(size_t bin) const {
                        return m_bins_name[bin];
                    }

                    size_t nBins() const {
                        return m_bins_name.size();
                    }

                    const std::vector<std::string>& getVariablesName() const {
                        return m_variables_name;
                    }

                    const std::vector<Binning>& getVariables() const {
                        return m_variables;
                    }

                    std::string getVariableName(size_t variable) const {
                        return m_variables_name[variable];
                    }

                    size_t nVariables() const {
                        return m_variables.size();
                    }

                    const std::vector<std::string>& getParametersName() const { return m_parameters_name; }

                    size_t nParameters() const { return m_parameters_name.size(); }

                    std::string getFormulaString() const {
                        return m_formula_str;
                    }

#ifndef STANDALONE
                    const reco::FormulaEvaluator* getFormula() const {
                        return m_formula.get();
                    }
#else
                    TFormula const * getFormula() const {
                        return m_formula.get();
                    }
#endif
                    void init();

                private:
                    std::vector<std::string> m_bins_name;
                    std::vector<std::string> m_variables_name;
                    std::string m_formula_str;

#ifndef STANDALONE
                    std::shared_ptr<reco::FormulaEvaluator> m_formula COND_TRANSIENT;
#else
                    std::shared_ptr<TFormula> m_formula COND_TRANSIENT;
#endif
                    std::vector<Binning> m_bins COND_TRANSIENT;
                    std::vector<Binning> m_variables COND_TRANSIENT;
                    std::vector<std::string> m_parameters_name COND_TRANSIENT;

                    COND_SERIALIZABLE
            };

            class Record {
                public:
                    Record() {
                        // Empty
                    }

                    Record(const std::string& record, const Definition& def);

                    const std::vector<Range>& getBinsRange() const {
                        return m_bins_range;
                    }

                    const std::vector<Range>& getVariablesRange() const {
                        return m_variables_range;
                    }

                    const std::vector<float>& getParametersValues() const {
                        return m_parameters_values;
                    }

                    size_t nVariables() const {
                        return m_variables_range.size();
                    }

                    size_t nParameters() const {
                        return m_parameters_values.size();    
                    }

                private:
                    std::vector<Range> m_bins_range;
                    std::vector<Range> m_variables_range;
                    std::vector<float> m_parameters_values;

                    COND_SERIALIZABLE
            };

        public:
            JetResolutionObject(const std::string& filename);
            JetResolutionObject(const JetResolutionObject& filename);
            JetResolutionObject();

            void dump() const;
            void saveToFile(const std::string& file) const;

            const Record* getRecord(const JetParameters& bins) const;
            float evaluateFormula(const Record& record, const JetParameters& variables) const;

            const std::vector<Record>& getRecords() const {
                return m_records;
            }

            const Definition& getDefinition() const {
                return m_definition;
            }

        private:
            Definition m_definition;
            std::vector<Record> m_records;

            bool m_valid = false;

            COND_SERIALIZABLE
    };
}

#endif

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