ChiSquareFunctionUpdator.h

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#ifndef RecoTauTag_ImpactParameter_ChiSquareFunctionUpdator_h
#define RecoTauTag_ImpactParameter_ChiSquareFunctionUpdator_h
 
/* From SimpleFits Package
 * Designed an written by
 * author: Ian M. Nugent
 * Humboldt Foundations
 */
 
#include "Minuit2/FCNBase.h"
#include "TMatrixT.h"
#include "TVectorT.h"
#include "RecoTauTag/ImpactParameter/interface/TrackHelixVertexFitter.h"
 
namespace tauImpactParameter {
 
  class ChiSquareFunctionUpdator : public ROOT::Minuit2::FCNBase {
  public:
    ChiSquareFunctionUpdator(TrackHelixVertexFitter* VF) { VF_ = VF; }
    ~ChiSquareFunctionUpdator() override{};
 
    double operator()(const std::vector<double>& x) const override {
      TVectorT<double> X(x.size());
      for (unsigned int i = 0; i < x.size(); ++i) {
        X(i) = x[i];
      }
      return VF_->updateChisquare(X);
    }
    double Up() const override {
      return 1.0;
    }  // Error definiton for Chi^2 (virtual function defined in ROOT::Minuit2::FCNBase base-class)
 
  private:
    TrackHelixVertexFitter* VF_;
  };
 
}  // namespace tauImpactParameter
#endif