Utilities/interface/RooFitFunction.h

0001 #ifndef PhysicsTools_Utilities_RooFitFunction_h
0002 #define PhysicsTools_Utilities_RooFitFunction_h
0003
0004 #include "PhysicsTools/Utilities/interface/Parameter.h"
0005 #include "RooAbsReal.h"
0006 #include "RooListProxy.h"
0007 #include "RooRealProxy.h"
0008
0009 #include <iostream>
0010 #include <vector>
0011
0012 namespace root {
0013   struct no_args;
0014
0015   template <typename X, typename Expr>
0016   class RooFitFunction : public RooAbsReal {
0017   public:
0018     RooFitFunction(const RooFitFunction<X, Expr>& other, const char* name = nullptr)
0019         : RooAbsReal(other, name),
0020           e_(other.e_),
0021           x_(X::name(), this, other.x_),
0022           parsPtrs_{other.parsPtrs_},
0023           parsArgs_{"!pars", this, other.parsArgs_} {}
0024     RooFitFunction(const char* name, const char* title, const Expr& e, RooAbsReal& x)
0025         : RooAbsReal(name, title),
0026           e_(e),
0027           x_(X::name(), X::name(), this, x),
0028           parsArgs_("!pars", "List of parameters", this) {}
0029     RooFitFunction(
0030         const char* name, const char* title, const Expr& e, RooAbsReal& x, RooAbsReal& rA, funct::Parameter& a)
0031         : RooFitFunction{name, title, e, x} {
0032       add(rA, a);
0033     }
0034     RooFitFunction(const char* name,
0035                    const char* title,
0036                    const Expr& e,
0037                    RooAbsReal& x,
0038                    RooAbsReal& rA,
0039                    funct::Parameter& a,
0040                    RooAbsReal& rB,
0041                    funct::Parameter& b)
0042         : RooFitFunction{name, title, e, x, rA, a} {
0043       add(rB, b);
0044     }
0045     RooFitFunction(const char* name,
0046                    const char* title,
0047                    const Expr& e,
0048                    RooAbsReal& x,
0049                    RooAbsReal& rA,
0050                    funct::Parameter& a,
0051                    RooAbsReal& rB,
0052                    funct::Parameter& b,
0053                    RooAbsReal& rC,
0054                    funct::Parameter& c)
0055         : RooFitFunction{name, title, e, x, rA, a, rB, b} {
0056       add(rC, c);
0057     }
0058     void add(RooAbsReal& rA, funct::Parameter& a) {
0059       parsPtrs_.emplace_back(a.ptr());
0060       parsArgs_.add(rA);
0061     }
0062     TObject* clone(const char* newName) const override { return new RooFitFunction<X, Expr>(*this, newName); }
0063
0064   private:
0065     Expr e_;
0066     RooRealProxy x_;
0067     std::vector<std::shared_ptr<double>> parsPtrs_;
0068     RooListProxy parsArgs_;
0069     Double_t evaluate() const override {
0070       X::set(x_);
0071       for (std::size_t i = 0; i < parsPtrs_.size(); ++i) {
0072         *(parsPtrs_[i]) = static_cast<RooAbsReal const&>(parsArgs_[i]).getVal(parsArgs_.nset());
0073       }
0074       return e_();
0075     }
0076   };
0077
0078 }  // namespace root
0079
0080 #endif