Chi2MinimumFinder1D.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <vector>
#include <algorithm>
#include <string>
#include <memory>
#include <TH1F.h>
#include <TH1D.h>
 
namespace Belle2 {
  namespace TOP {
 
    class Chi2MinimumFinder1D {
 
    public:
 
      struct Minimum {
        double position = 0; 
        double error = 0;    
        double chi2 = 0;     
        bool valid = false;  
        Minimum()
        {}
 
        Minimum(double pos, double err, double chi2_min, bool valid_flag):
          position(pos), error(err), chi2(chi2_min), valid(valid_flag)
        {}
      };
 
      Chi2MinimumFinder1D()
      {}
 
      Chi2MinimumFinder1D(int nbins, double xmin, double xmax);
 
      explicit Chi2MinimumFinder1D(const std::shared_ptr<TH1D> h);
 
      void clear();
 
      void add(unsigned i, double chi2);
 
      Chi2MinimumFinder1D& add(const Chi2MinimumFinder1D& other);
 
      double getXmin() const {return m_xmin;}
 
      double getXmax() const {return m_xmax;}
 
      int getNbins() const {return m_x.size();}
 
      double getBinSize() const {return m_dx;}
 
      const std::vector<double>& getBinCenters() const {return m_x;}
 
      const std::vector<double>& getChi2Values() const {return m_chi2;}
 
 
      double getMinChi2() const {return *std::min_element(m_chi2.begin(), m_chi2.end());}
 
      int getEntries() const {return m_entries;}
 
      const Minimum& getMinimum()
      {
        if (!m_searched) {
          findMinimum();
          m_searched = true;
        }
        return m_minimum;
      }
 
      TH1F getHistogram(std::string name, std::string title) const;
 
    private:
 
      void findMinimum();
 
      Minimum getMinimum(double yLeft, double yCenter, double yRight) const;
 
      double m_xmin = 0; 
      double m_xmax = 0; 
      double m_dx = 0; 
      std::vector<double> m_x;  
      std::vector<double> m_chi2; 
      int m_entries = 0; 
      bool m_searched = false; 
      Minimum m_minimum; 
    };
 
  } // namespace TOP
} // namespace Belle2