CbmRichRingFitterEllipseMinuit.h

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/* Copyright (C) 2011-2015 UGiessen/JINR-LIT, Giessen/Dubna
   SPDX-License-Identifier: GPL-3.0-only
   Authors: Semen Lebedev [committer], Florian Uhlig */
 
#ifndef CBM_RICH_RING_FITTER_ELLIPSE_MINUIT
#define CBM_RICH_RING_FITTER_ELLIPSE_MINUIT
 
#include "CbmRichRingFitterEllipseBase.h"
#include "Math/IFunction.h"
#include "Rtypes.h"
 
#include <vector>
 
using std::vector;
 
class FCNEllipse2 : public ROOT::Math::IBaseFunctionMultiDim {
 private:
  vector<Double_t> fX;  // vector of X coordinates
  vector<Double_t> fY;  // vector of Y coordinates
 public:
  FCNEllipse2(vector<Double_t> x, vector<Double_t> y) : ROOT::Math::IBaseFunctionMultiDim(), fX(x), fY(y) {}
 
  double DoEval(const double* x) const
  {
    Double_t r = 0.;
    for (UInt_t i = 0; i < fX.size(); i++) {
      Double_t ri = calcE(i, x);
      r += ri * ri;
    }
    return r;
  }
 
  Double_t calcE(Int_t i, const double* par) const
  {
    Double_t d1 = sqrt((fX[i] - par[0]) * (fX[i] - par[0]) + (fY[i] - par[1]) * (fY[i] - par[1]));
    Double_t d2 = sqrt((fX[i] - par[2]) * (fX[i] - par[2]) + (fY[i] - par[3]) * (fY[i] - par[3]));
    Double_t ri = d1 + d2 - 2 * par[4];
    return ri;
  }
 
  unsigned int NDim() const { return 5; }
 
  ROOT::Math::IBaseFunctionMultiDim* Clone() const { return new FCNEllipse2(fX, fY); }
};
 
 
class CbmRichRingFitterEllipseMinuit : public CbmRichRingFitterEllipseBase {
 public:
  CbmRichRingFitterEllipseMinuit();
 
  virtual ~CbmRichRingFitterEllipseMinuit();
 
  virtual void DoFit(CbmRichRingLight* ring);
 
 private:
  vector<double> DoFit(const vector<double>& x, const vector<double>& y);
 
  void TransformToRichRing(CbmRichRingLight* ring, const vector<double>& par);
};
 
#endif