CbmRichRingFitterBase.h

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/* Copyright (C) 2012 UGiessen/JINR-LIT, Giessen/Dubna
   SPDX-License-Identifier: GPL-3.0-only
   Authors: Semen Lebedev [committer] */
 
#ifndef CBM_RICH_RING_FITTER_BASE
#define CBM_RICH_RING_FITTER_BASE
 
#include "CbmRichRingLight.h"
class CbmRichRingFitterBase {
 public:
  CbmRichRingFitterBase() {}
 
  virtual ~CbmRichRingFitterBase() {}
 
  virtual void DoFit(CbmRichRingLight* ring) = 0;
 
 protected:
  virtual void CalcChi2(CbmRichRingLight* ring)
  {
    int nofHits = ring->GetNofHits();
    if (nofHits < 4) {
      ring->SetChi2(-1.);
      return;
    }
 
    float chi2 = 0.;
    float r    = ring->GetRadius();
    float xc   = ring->GetCenterX();
    float yc   = ring->GetCenterY();
 
    for (int i = 0; i < nofHits; i++) {
      float xh = ring->GetHit(i).fX;
      float yh = ring->GetHit(i).fY;
      float d  = r - sqrt((xc - xh) * (xc - xh) + (yc - yh) * (yc - yh));
 
      chi2 += d * d;
    }
    ring->SetChi2(chi2);
  }
 
  static const int MAX_NOF_HITS_IN_RING = 400;  // maximum possible number of hits
};
 
#endif