CbmRichRingFitterEllipseMinuit.h

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#ifndef CBM_RICH_RING_FITTER_ELLIPSE_MINUIT
#define CBM_RICH_RING_FITTER_ELLIPSE_MINUIT

#include "CbmRichRingFitterEllipseBase.h"
#include "TFitterMinuit.h"
#include <vector>

using std::vector;

class FCNEllipse : public ROOT::Minuit2::FCNBase {
public:
   FCNEllipse(
         const vector<Double_t>& x,
         const vector<Double_t>& y) :
            fX(x),
            fY(y),
            fErrorDef(1.)
   {

   }

   ~FCNEllipse()
   {

   }

   virtual Double_t Up() const
   {
      return fErrorDef;
   }

   virtual Double_t operator()(
         const vector<Double_t>& par) const
   {
      Double_t r = 0.;
      for(UInt_t i = 0; i < fX.size(); i++) {
         Double_t ri = calcE(i, par);
         r +=   ri * ri;
      }
      return r;
   }

   Double_t calcE(
         Int_t i,
         const vector<Double_t>& 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;
    }


   vector<Double_t> X() const {return fX;}

   vector<Double_t> Y() const {return fY;}

   void SetErrorDef(Double_t def) {fErrorDef = def;}

private:
    vector<Double_t> fX; // vector of X coordinates
    vector<Double_t> fY; // vector of Y coordinates
    Double_t fErrorDef;
};

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